Google Git
Sign in
android / platform / development / 6698b7a / . / samples / XmlAdapters / src / com / example / android / xmladapters / Adapters.java
blob: 2fbfb3485fe3db350eab68a318db11902d98a2e2 [file] [log] [blame]
/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.xmladapters;
import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.AsyncTask;
import android.util.AttributeSet;
import android.util.Xml;
import android.view.View;
import android.widget.BaseAdapter;
import android.widget.CursorAdapter;
import android.widget.ImageView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.HashMap;
/**
* <p>This class can be used to load {@link android.widget.Adapter adapters} defined in
* XML resources. XML-defined adapters can be used to easily create adapters in your
* own application or to pass adapters to other processes.</p>
*
* <h2>Types of adapters</h2>
* <p>Adapters defined using XML resources can only be one of the following supported
* types. Arbitrary adapters are not supported to guarantee the safety of the loaded
* code when adapters are loaded across packages.</p>
* <ul>
* <li><a href="#xml-cursor-adapter">Cursor adapter</a>: a cursor adapter can be used
* to display the content of a cursor, most often coming from a content provider</li>
* </ul>
* <p>The complete XML format definition of each adapter type is available below.</p>
*
* <a name="xml-cursor-adapter"></a>
* <h2>Cursor adapter</h2>
* <p>A cursor adapter XML definition starts with the
* <a href="#xml-cursor-adapter-tag"><code>&lt;cursor-adapter /&gt;</code></a>
* tag and may contain one or more instances of the following tags:</p>
* <ul>
* <li><a href="#xml-cursor-adapter-select-tag"><code>&lt;select /&gt;</code></a></li>
* <li><a href="#xml-cursor-adapter-bind-tag"><code>&lt;bind /&gt;</code></a></li>
* </ul>
*
* <a name="xml-cursor-adapter-tag"></a>
* <h3>&lt;cursor-adapter /&gt;</h3>
* <p>The <code>&lt;cursor-adapter /&gt;</code> element defines the beginning of the
* document and supports the following attributes:</p>
* <ul>
* <li><code>android:layout</code>: Reference to the XML layout to be inflated for
* each item of the adapter. This attribute is mandatory.</li>
* <li><code>android:selection</code>: Selection expression, used when the
* <code>android:uri</code> attribute is defined or when the adapter is loaded with
* {@link Adapters#loadCursorAdapter(android.content.Context, int, String, Object[])}.
* This attribute is optional.</li>
* <li><code>android:sortOrder</code>: Sort expression, used when the
* <code>android:uri</code> attribute is defined or when the adapter is loaded with
* {@link Adapters#loadCursorAdapter(android.content.Context, int, String, Object[])}.
* This attribute is optional.</li>
* <li><code>android:uri</code>: URI of the content provider to query to retrieve a cursor.
* Specifying this attribute is equivalent to calling
* {@link Adapters#loadCursorAdapter(android.content.Context, int, String, Object[])}.
* If you call this method, the value of the XML attribute is ignored. This attribute is
* optional.</li>
* </ul>
* <p>In addition, you can specify one or more instances of
* <a href="#xml-cursor-adapter-select-tag"><code>&lt;select /&gt;</code></a> and
* <a href="#xml-cursor-adapter-bind-tag"><code>&lt;bind /&gt;</code></a> tags as children
* of <code>&lt;cursor-adapter /&gt;</code>.</p>
*
* <a name="xml-cursor-adapter-select-tag"></a>
* <h3>&lt;select /&gt;</h3>
* <p>The <code>&lt;select /&gt;</code> tag is used to select columns from the cursor
* when doing the query. This can be very useful when using transformations in the
* <code>&lt;bind /&gt;</code> elements. It can also be very useful if you are providing
* your own <a href="#xml-cursor-adapter-bind-data-types">binder</a> or
* <a href="#xml-cursor-adapter-bind-data-types">transformation</a> classes.
* <code>&lt;select /&gt;</code> elements are ignored if you supply the cursor yourself.</p>
* <p>The <code>&lt;select /&gt;</code> supports the following attributes:</p>
* <ul>
* <li><code>android:column</code>: Name of the column to select in the cursor during the
* query operation</li>
* </ul>
* <p><strong>Note:</strong> The column named <code>_id</code> is always implicitly
* selected.</p>
*
* <a name="xml-cursor-adapter-bind-tag"></a>
* <h3>&lt;bind /&gt;</h3>
* <p>The <code>&lt;bind /&gt;</code> tag is used to bind a column from the cursor to
* a {@link android.view.View}. A column bound using this tag is automatically selected
* during the query and a matching
* <a href="#xml-cursor-adapter-select-tag"><code>&lt;select /&gt;</code> tag is therefore
* not required.</p>
*
* <p>Each binding is declared as a one to one matching but
* custom binder classes or special
* <a href="#xml-cursor-adapter-bind-data-transformation">data transformations</a> can
* allow you to bind several columns to a single view. In this case you must use the
* <a href="#xml-cursor-adapter-select-tag"><code>&lt;select /&gt;</code> tag to make
* sure any required column is part of the query.</p>
*
* <p>The <code>&lt;bind /&gt;</code> tag supports the following attributes:</p>
* <ul>
* <li><code>android:from</code>: The name of the column to bind from.
* This attribute is mandatory. Note that <code>@</code> which are not used to reference resources
* should be backslash protected as in <code>\@</code>.</li>
* <li><code>android:to</code>: The id of the view to bind to. This attribute is mandatory.</li>
* <li><code>android:as</code>: The <a href="#xml-cursor-adapter-bind-data-types">data type</a>
* of the binding. This attribute is mandatory.</li>
* </ul>
*
* <p>In addition, a <code>&lt;bind /&gt;</code> can contain zero or more instances of
* <a href="#xml-cursor-adapter-bind-data-transformation">data transformations</a> children
* tags.</p>
*
* <a name="xml-cursor-adapter-bind-data-types"></a>
* <h4>Binding data types</h4>
* <p>For a binding to occur the data type of the bound column/view pair must be specified.
* The following data types are currently supported:</p>
* <ul>
* <li><code>string</code>: The content of the column is interpreted as a string and must be
* bound to a {@link android.widget.TextView}</li>
* <li><code>image</code>: The content of the column is interpreted as a blob describing an
* image and must be bound to an {@link android.widget.ImageView}</li>
* <li><code>image-uri</code>: The content of the column is interpreted as a URI to an image
* and must be bound to an {@link android.widget.ImageView}</li>
* <li><code>drawable</code>: The content of the column is interpreted as a resource id to a
* drawable and must be bound to an {@link android.widget.ImageView}</li>
* <li><code>tag</code>: The content of the column is interpreted as a string and will be set as
* the tag (using {@link View#setTag(Object)} of the associated View. This can be used to
* associate meta-data to your view, that can be used for instance by a listener.</li>
* <li>A fully qualified class name: The name of a class corresponding to an implementation of
* {@link Adapters.CursorBinder}. Cursor binders can be used to provide
* bindings not supported by default. Custom binders cannot be used with
* {@link android.content.Context#isRestricted() restricted contexts}, for instance in an
* application widget</li>
* </ul>
*
* <a name="xml-cursor-adapter-bind-transformation"></a>
* <h4>Binding transformations</h4>
* <p>When defining a data binding you can specify an optional transformation by using one
* of the following tags as a child of a <code>&lt;bind /&gt;</code> elements:</p>
* <ul>
* <li><code>&lt;map /&gt;</code>: Maps a constant string to a string or a resource. Use
* one instance of this tag per value you want to map</li>
* <li><code>&lt;transform /&gt;</code>: Transforms a column's value using an expression
* or an instance of {@link Adapters.CursorTransformation}</li>
* </ul>
* <p>While several <code>&lt;map /&gt;</code> tags can be used at the same time, you cannot
* mix <code>&lt;map /&gt;</code> and <code>&lt;transform /&gt;</code> tags. If several
* <code>&lt;transform /&gt;</code> tags are specified, only the last one is retained.</p>
*
* <a name="xml-cursor-adapter-bind-transformation-map" />
* <p><strong>&lt;map /&gt;</strong></p>
* <p>A map element simply specifies a value to match from and a value to match to. When
* a column's value equals the value to match from, it is replaced with the value to match
* to. The following attributes are supported:</p>
* <ul>
* <li><code>android:fromValue</code>: The value to match from. This attribute is mandatory</li>
* <li><code>android:toValue</code>: The value to match to. This value can be either a string
* or a resource identifier. This value is interpreted as a resource identifier when the
* data binding is of type <code>drawable</code>. This attribute is mandatory</li>
* </ul>
*
* <a name="xml-cursor-adapter-bind-transformation-transform"></a>
* <p><strong>&lt;transform /&gt;</strong></p>
* <p>A simple transform that occurs either by calling a specified class or by performing
* simple text substitution. The following attributes are supported:</p>
* <ul>
* <li><code>android:withExpression</code>: The transformation expression. The expression is
* a string containing column names surrounded with curly braces { and }. During the
* transformation each column name is replaced by its value. All columns must have been
* selected in the query. An example of expression is <code>"First name: {first_name},
* last name: {last_name}"</code>. This attribute is mandatory
* if <code>android:withClass</code> is not specified and ignored if <code>android:withClass</code>
* is specified</li>
* <li><code>android:withClass</code>: A fully qualified class name corresponding to an
* implementation of {@link Adapters.CursorTransformation}. Custom
* transformations cannot be used with
* {@link android.content.Context#isRestricted() restricted contexts}, for instance in
* an app widget This attribute is mandatory if <code>android:withExpression</code> is
* not specified</li>
* </ul>
*
* <h3>Example</h3>
* <p>The following example defines a cursor adapter that queries all the contacts with
* a phone number using the contacts content provider. Each contact is displayed with
* its display name, its favorite status and its photo. To display photos, a custom data
* binder is declared:</p>
*
* <pre class="prettyprint">
* &lt;cursor-adapter xmlns:android="http://schemas.android.com/apk/res/android"
* android:uri="content://com.android.contacts/contacts"
* android:selection="has_phone_number=1"
* android:layout="@layout/contact_item"&gt;
*
* &lt;bind android:from="display_name" android:to="@id/name" android:as="string" /&gt;
* &lt;bind android:from="starred" android:to="@id/star" android:as="drawable"&gt;
* &lt;map android:fromValue="0" android:toValue="@android:drawable/star_big_off" /&gt;
* &lt;map android:fromValue="1" android:toValue="@android:drawable/star_big_on" /&gt;
* &lt;/bind&gt;
* &lt;bind android:from="_id" android:to="@id/name"
* android:as="com.google.android.test.adapters.ContactPhotoBinder" /&gt;
*
* &lt;/cursor-adapter&gt;
* </pre>
*
* <h3>Related APIs</h3>
* <ul>
* <li>{@link Adapters#loadAdapter(android.content.Context, int, Object[])}</li>
* <li>{@link Adapters#loadCursorAdapter(android.content.Context, int, android.database.Cursor, Object[])}</li>
* <li>{@link Adapters#loadCursorAdapter(android.content.Context, int, String, Object[])}</li>
* <li>{@link Adapters.CursorBinder}</li>
* <li>{@link Adapters.CursorTransformation}</li>
* <li>{@link android.widget.CursorAdapter}</li>
* </ul>
*
* @see android.widget.Adapter
* @see android.content.ContentProvider
*
* attr ref android.R.styleable#CursorAdapter_layout
* attr ref android.R.styleable#CursorAdapter_selection
* attr ref android.R.styleable#CursorAdapter_sortOrder
* attr ref android.R.styleable#CursorAdapter_uri
* attr ref android.R.styleable#CursorAdapter_BindItem_as
* attr ref android.R.styleable#CursorAdapter_BindItem_from
* attr ref android.R.styleable#CursorAdapter_BindItem_to
* attr ref android.R.styleable#CursorAdapter_MapItem_fromValue
* attr ref android.R.styleable#CursorAdapter_MapItem_toValue
* attr ref android.R.styleable#CursorAdapter_SelectItem_column
* attr ref android.R.styleable#CursorAdapter_TransformItem_withClass
* attr ref android.R.styleable#CursorAdapter_TransformItem_withExpression
*/
public class Adapters {
private static final String ADAPTER_CURSOR = "cursor-adapter";
/**
* <p>Interface used to bind a {@link android.database.Cursor} column to a View. This
* interface can be used to provide bindings for data types not supported by the
* standard implementation of {@link Adapters}.</p>
*
* <p>A binder is provided with a cursor transformation which may or may not be used
* to transform the value retrieved from the cursor. The transformation is guaranteed
* to never be null so it's always safe to apply the transformation.</p>
*
* <p>The binder is associated with a Context but can be re-used with multiple cursors.
* As such, the implementation should make no assumption about the Cursor in use.</p>
*
* @see android.view.View
* @see android.database.Cursor
* @see Adapters.CursorTransformation
*/
public static abstract class CursorBinder {
/**
* <p>The context associated with this binder.</p>
*/
protected final Context mContext;
/**
* <p>The transformation associated with this binder. This transformation is never
* null and may or may not be applied to the Cursor data during the
* {@link #bind(android.view.View, android.database.Cursor, int)} operation.</p>
*
* @see #bind(android.view.View, android.database.Cursor, int)
*/
protected final CursorTransformation mTransformation;
/**
* <p>Creates a new Cursor binder.</p>
*
* @param context The context associated with this binder.
* @param transformation The transformation associated with this binder. This
* transformation may or may not be applied by the binder and is guaranteed
* to not be null.
*/
public CursorBinder(Context context, CursorTransformation transformation) {
mContext = context;
mTransformation = transformation;
}
/**
* <p>Binds the specified Cursor column to the supplied View. The binding operation
* can query other Cursor columns as needed. During the binding operation, values
* retrieved from the Cursor may or may not be transformed using this binder's
* cursor transformation.</p>
*
* @param view The view to bind data to.
* @param cursor The cursor to bind data from.
* @param columnIndex The column index in the cursor where the data to bind resides.
*
* @see #mTransformation
*
* @return True if the column was successfully bound to the View, false otherwise.
*/
public abstract boolean bind(View view, Cursor cursor, int columnIndex);
}
/**
* <p>Interface used to transform data coming out of a {@link android.database.Cursor}
* before it is bound to a {@link android.view.View}.</p>
*
* <p>Transformations are used to transform text-based data (in the form of a String),
* or to transform data into a resource identifier. A default implementation is provided
* to generate resource identifiers.</p>
*
* @see android.database.Cursor
* @see Adapters.CursorBinder
*/
public static abstract class CursorTransformation {
/**
* <p>The context associated with this transformation.</p>
*/
protected final Context mContext;
/**
* <p>Creates a new Cursor transformation.</p>
*
* @param context The context associated with this transformation.
*/
public CursorTransformation(Context context) {
mContext = context;
}
/**
* <p>Transforms the specified Cursor column into a String. The transformation
* can simply return the content of the column as a String (this is known
* as the identity transformation) or manipulate the content. For instance,
* a transformation can perform text substitutions or concatenate other
* columns with the specified column.</p>
*
* @param cursor The cursor that contains the data to transform.
* @param columnIndex The index of the column to transform.
*
* @return A String containing the transformed value of the column.
*/
public abstract String transform(Cursor cursor, int columnIndex);
/**
* <p>Transforms the specified Cursor column into a resource identifier.
* The default implementation simply interprets the content of the column
* as an integer.</p>
*
* @param cursor The cursor that contains the data to transform.
* @param columnIndex The index of the column to transform.
*
* @return A resource identifier.
*/
public int transformToResource(Cursor cursor, int columnIndex) {
return cursor.getInt(columnIndex);
}
}
/**
* <p>Loads the {@link android.widget.CursorAdapter} defined in the specified
* XML resource. The content of the adapter is loaded from the content provider
* identified by the supplied URI.</p>
*
* <p><strong>Note:</strong> If the supplied {@link android.content.Context} is
* an {@link android.app.Activity}, the cursor returned by the content provider
* will be automatically managed. Otherwise, you are responsible for managing the
* cursor yourself.</p>
*
* <p>The format of the XML definition of the cursor adapter is documented at
* the top of this page.</p>
*
* @param context The context to load the XML resource from.
* @param id The identifier of the XML resource declaring the adapter.
* @param uri The URI of the content provider.
* @param parameters Optional parameters to pass to the CursorAdapter, used
* to substitute values in the selection expression.
*
* @return A {@link android.widget.CursorAdapter}
*
* @throws IllegalArgumentException If the XML resource does not contain
* a valid &lt;cursor-adapter /&gt; definition.
*
* @see android.content.ContentProvider
* @see android.widget.CursorAdapter
* @see #loadAdapter(android.content.Context, int, Object[])
*/
public static CursorAdapter loadCursorAdapter(Context context, int id, String uri,
Object... parameters) {
XmlCursorAdapter adapter = (XmlCursorAdapter) loadAdapter(context, id, ADAPTER_CURSOR,
parameters);
if (uri != null) {
adapter.setUri(uri);
}
adapter.load();
return adapter;
}
/**
* <p>Loads the {@link android.widget.CursorAdapter} defined in the specified
* XML resource. The content of the adapter is loaded from the specified cursor.
* You are responsible for managing the supplied cursor.</p>
*
* <p>The format of the XML definition of the cursor adapter is documented at
* the top of this page.</p>
*
* @param context The context to load the XML resource from.
* @param id The identifier of the XML resource declaring the adapter.
* @param cursor The cursor containing the data for the adapter.
* @param parameters Optional parameters to pass to the CursorAdapter, used
* to substitute values in the selection expression.
*
* @return A {@link android.widget.CursorAdapter}
*
* @throws IllegalArgumentException If the XML resource does not contain
* a valid &lt;cursor-adapter /&gt; definition.
*
* @see android.content.ContentProvider
* @see android.widget.CursorAdapter
* @see android.database.Cursor
* @see #loadAdapter(android.content.Context, int, Object[])
*/
public static CursorAdapter loadCursorAdapter(Context context, int id, Cursor cursor,
Object... parameters) {
XmlCursorAdapter adapter = (XmlCursorAdapter) loadAdapter(context, id, ADAPTER_CURSOR,
parameters);
if (cursor != null) {
adapter.changeCursor(cursor);
}
return adapter;
}
/**
* <p>Loads the adapter defined in the specified XML resource. The XML definition of
* the adapter must follow the format definition of one of the supported adapter
* types described at the top of this page.</p>
*
* <p><strong>Note:</strong> If the loaded adapter is a {@link android.widget.CursorAdapter}
* and the supplied {@link android.content.Context} is an {@link android.app.Activity},
* the cursor returned by the content provider will be automatically managed. Otherwise,
* you are responsible for managing the cursor yourself.</p>
*
* @param context The context to load the XML resource from.
* @param id The identifier of the XML resource declaring the adapter.
* @param parameters Optional parameters to pass to the adapter.
*
* @return An adapter instance.
*
* @see #loadCursorAdapter(android.content.Context, int, android.database.Cursor, Object[])
* @see #loadCursorAdapter(android.content.Context, int, String, Object[])
*/
public static BaseAdapter loadAdapter(Context context, int id, Object... parameters) {
final BaseAdapter adapter = loadAdapter(context, id, null, parameters);
if (adapter instanceof ManagedAdapter) {
((ManagedAdapter) adapter).load();
}
return adapter;
}
/**
* Loads an adapter from the specified XML resource. The optional assertName can
* be used to exit early if the adapter defined in the XML resource is not of the
* expected type.
*
* @param context The context to associate with the adapter.
* @param id The resource id of the XML document defining the adapter.
* @param assertName The mandatory name of the adapter in the XML document.
* Ignored if null.
* @param parameters Optional parameters passed to the adapter.
*
* @return An instance of {@link android.widget.BaseAdapter}.
*/
private static BaseAdapter loadAdapter(Context context, int id, String assertName,
Object... parameters) {
XmlResourceParser parser = null;
try {
parser = context.getResources().getXml(id);
return createAdapterFromXml(context, parser, Xml.asAttributeSet(parser),
id, parameters, assertName);
} catch (XmlPullParserException ex) {
Resources.NotFoundException rnf = new Resources.NotFoundException(
"Can't load adapter resource ID " +
context.getResources().getResourceEntryName(id));
rnf.initCause(ex);
throw rnf;
} catch (IOException ex) {
Resources.NotFoundException rnf = new Resources.NotFoundException(
"Can't load adapter resource ID " +
context.getResources().getResourceEntryName(id));
rnf.initCause(ex);
throw rnf;
} finally {
if (parser != null) parser.close();
}
}
/**
* Generates an adapter using the specified XML parser. This method is responsible
* for choosing the type of the adapter to create based on the content of the
* XML parser.
*
* This method will generate an {@link IllegalArgumentException} if
* <code>assertName</code> is not null and does not match the root tag of the XML
* document.
*/
private static BaseAdapter createAdapterFromXml(Context c,
XmlPullParser parser, AttributeSet attrs, int id, Object[] parameters,
String assertName) throws XmlPullParserException, IOException {
BaseAdapter adapter = null;
// Make sure we are on a start tag.
int type;
int depth = parser.getDepth();
while (((type = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth) &&
type != XmlPullParser.END_DOCUMENT) {
if (type != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (assertName != null && !assertName.equals(name)) {
throw new IllegalArgumentException("The adapter defined in " +
c.getResources().getResourceEntryName(id) + " must be a <" +
assertName + " />");
}
if (ADAPTER_CURSOR.equals(name)) {
adapter = createCursorAdapter(c, parser, attrs, id, parameters);
} else {
throw new IllegalArgumentException("Unknown adapter name " + parser.getName() +
" in " + c.getResources().getResourceEntryName(id));
}
}
return adapter;
}
/**
* Creates an XmlCursorAdapter using an XmlCursorAdapterParser.
*/
private static XmlCursorAdapter createCursorAdapter(Context c, XmlPullParser parser,
AttributeSet attrs, int id, Object[] parameters)
throws IOException, XmlPullParserException {
return new XmlCursorAdapterParser(c, parser, attrs, id).parse(parameters);
}
/**
* Parser that can generate XmlCursorAdapter instances. This parser is responsible for
* handling all the attributes and child nodes for a &lt;cursor-adapter /&gt;.
*/
private static class XmlCursorAdapterParser {
private static final String ADAPTER_CURSOR_BIND = "bind";
private static final String ADAPTER_CURSOR_SELECT = "select";
private static final String ADAPTER_CURSOR_AS_STRING = "string";
private static final String ADAPTER_CURSOR_AS_IMAGE = "image";
private static final String ADAPTER_CURSOR_AS_TAG = "tag";
private static final String ADAPTER_CURSOR_AS_IMAGE_URI = "image-uri";
private static final String ADAPTER_CURSOR_AS_DRAWABLE = "drawable";
private static final String ADAPTER_CURSOR_MAP = "map";
private static final String ADAPTER_CURSOR_TRANSFORM = "transform";
private final Context mContext;
private final XmlPullParser mParser;
private final AttributeSet mAttrs;
private final int mId;
private final HashMap<String, CursorBinder> mBinders;
private final ArrayList<String> mFrom;
private final ArrayList<Integer> mTo;
private final CursorTransformation mIdentity;
private final Resources mResources;
public XmlCursorAdapterParser(Context c, XmlPullParser parser, AttributeSet attrs, int id) {
mContext = c;
mParser = parser;
mAttrs = attrs;
mId = id;
mResources = mContext.getResources();
mBinders = new HashMap<String, CursorBinder>();
mFrom = new ArrayList<String>();
mTo = new ArrayList<Integer>();
mIdentity = new IdentityTransformation(mContext);
}
public XmlCursorAdapter parse(Object[] parameters)
throws IOException, XmlPullParserException {
Resources resources = mResources;
TypedArray a = resources.obtainAttributes(mAttrs, R.styleable.CursorAdapter);
String uri = a.getString(R.styleable.CursorAdapter_uri);
String selection = a.getString(R.styleable.CursorAdapter_selection);
String sortOrder = a.getString(R.styleable.CursorAdapter_sortOrder);
int layout = a.getResourceId(R.styleable.CursorAdapter_layout, 0);
if (layout == 0) {
throw new IllegalArgumentException("The layout specified in " +
resources.getResourceEntryName(mId) + " does not exist");
}
a.recycle();
XmlPullParser parser = mParser;
int type;
int depth = parser.getDepth();
while (((type = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth) &&
type != XmlPullParser.END_DOCUMENT) {
if (type != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (ADAPTER_CURSOR_BIND.equals(name)) {
parseBindTag();
} else if (ADAPTER_CURSOR_SELECT.equals(name)) {
parseSelectTag();
} else {
throw new RuntimeException("Unknown tag name " + parser.getName() + " in " +
resources.getResourceEntryName(mId));
}
}
String[] fromArray = mFrom.toArray(new String[mFrom.size()]);
int[] toArray = new int[mTo.size()];
for (int i = 0; i < toArray.length; i++) {
toArray[i] = mTo.get(i);
}
String[] selectionArgs = null;
if (parameters != null) {
selectionArgs = new String[parameters.length];
for (int i = 0; i < selectionArgs.length; i++) {
selectionArgs[i] = (String) parameters[i];
}
}
return new XmlCursorAdapter(mContext, layout, uri, fromArray, toArray, selection,
selectionArgs, sortOrder, mBinders);
}
private void parseSelectTag() {
TypedArray a = mResources.obtainAttributes(mAttrs,
R.styleable.CursorAdapter_SelectItem);
String fromName = a.getString(R.styleable.CursorAdapter_SelectItem_column);
if (fromName == null) {
throw new IllegalArgumentException("A select item in " +
mResources.getResourceEntryName(mId) +
" does not have a 'column' attribute");
}
a.recycle();
mFrom.add(fromName);
mTo.add(View.NO_ID);
}
private void parseBindTag() throws IOException, XmlPullParserException {
Resources resources = mResources;
TypedArray a = resources.obtainAttributes(mAttrs,
R.styleable.CursorAdapter_BindItem);
String fromName = a.getString(R.styleable.CursorAdapter_BindItem_from);
if (fromName == null) {
throw new IllegalArgumentException("A bind item in " +
resources.getResourceEntryName(mId) + " does not have a 'from' attribute");
}
int toName = a.getResourceId(R.styleable.CursorAdapter_BindItem_to, 0);
if (toName == 0) {
throw new IllegalArgumentException("A bind item in " +
resources.getResourceEntryName(mId) + " does not have a 'to' attribute");
}
String asType = a.getString(R.styleable.CursorAdapter_BindItem_as);
if (asType == null) {
throw new IllegalArgumentException("A bind item in " +
resources.getResourceEntryName(mId) + " does not have an 'as' attribute");
}
mFrom.add(fromName);
mTo.add(toName);
mBinders.put(fromName, findBinder(asType));
a.recycle();
}
private CursorBinder findBinder(String type) throws IOException, XmlPullParserException {
final XmlPullParser parser = mParser;
final Context context = mContext;
CursorTransformation transformation = mIdentity;
int tagType;
int depth = parser.getDepth();
final boolean isDrawable = ADAPTER_CURSOR_AS_DRAWABLE.equals(type);
while (((tagType = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
&& tagType != XmlPullParser.END_DOCUMENT) {
if (tagType != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (ADAPTER_CURSOR_TRANSFORM.equals(name)) {
transformation = findTransformation();
} else if (ADAPTER_CURSOR_MAP.equals(name)) {
if (!(transformation instanceof MapTransformation)) {
transformation = new MapTransformation(context);
}
findMap(((MapTransformation) transformation), isDrawable);
} else {
throw new RuntimeException("Unknown tag name " + parser.getName() + " in " +
context.getResources().getResourceEntryName(mId));
}
}
if (ADAPTER_CURSOR_AS_STRING.equals(type)) {
return new StringBinder(context, transformation);
} else if (ADAPTER_CURSOR_AS_TAG.equals(type)) {
return new TagBinder(context, transformation);
} else if (ADAPTER_CURSOR_AS_IMAGE.equals(type)) {
return new ImageBinder(context, transformation);
} else if (ADAPTER_CURSOR_AS_IMAGE_URI.equals(type)) {
return new ImageUriBinder(context, transformation);
} else if (isDrawable) {
return new DrawableBinder(context, transformation);
} else {
return createBinder(type, transformation);
}
}
private CursorBinder createBinder(String type, CursorTransformation transformation) {
if (mContext.isRestricted()) return null;
try {
final Class<?> klass = Class.forName(type, true, mContext.getClassLoader());
if (CursorBinder.class.isAssignableFrom(klass)) {
final Constructor<?> c = klass.getDeclaredConstructor(
Context.class, CursorTransformation.class);
return (CursorBinder) c.newInstance(mContext, transformation);
}
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException("Cannot instanciate binder type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + type, e);
} catch (NoSuchMethodException e) {
throw new IllegalArgumentException("Cannot instanciate binder type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + type, e);
} catch (InvocationTargetException e) {
throw new IllegalArgumentException("Cannot instanciate binder type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + type, e);
} catch (InstantiationException e) {
throw new IllegalArgumentException("Cannot instanciate binder type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + type, e);
} catch (IllegalAccessException e) {
throw new IllegalArgumentException("Cannot instanciate binder type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + type, e);
}
return null;
}
private void findMap(MapTransformation transformation, boolean drawable) {
Resources resources = mResources;
TypedArray a = resources.obtainAttributes(mAttrs,
R.styleable.CursorAdapter_MapItem);
String from = a.getString(R.styleable.CursorAdapter_MapItem_fromValue);
if (from == null) {
throw new IllegalArgumentException("A map item in " +
resources.getResourceEntryName(mId) +
" does not have a 'fromValue' attribute");
}
if (!drawable) {
String to = a.getString(R.styleable.CursorAdapter_MapItem_toValue);
if (to == null) {
throw new IllegalArgumentException("A map item in " +
resources.getResourceEntryName(mId) +
" does not have a 'toValue' attribute");
}
transformation.addStringMapping(from, to);
} else {
int to = a.getResourceId(R.styleable.CursorAdapter_MapItem_toValue, 0);
if (to == 0) {
throw new IllegalArgumentException("A map item in " +
resources.getResourceEntryName(mId) +
" does not have a 'toValue' attribute");
}
transformation.addResourceMapping(from, to);
}
a.recycle();
}
private CursorTransformation findTransformation() {
Resources resources = mResources;
CursorTransformation transformation = null;
TypedArray a = resources.obtainAttributes(mAttrs,
R.styleable.CursorAdapter_TransformItem);
String className = a.getString(R.styleable.CursorAdapter_TransformItem_withClass);
if (className == null) {
String expression = a.getString(
R.styleable.CursorAdapter_TransformItem_withExpression);
transformation = createExpressionTransformation(expression);
} else if (!mContext.isRestricted()) {
try {
final Class<?> klas = Class.forName(className, true, mContext.getClassLoader());
if (CursorTransformation.class.isAssignableFrom(klas)) {
final Constructor<?> c = klas.getDeclaredConstructor(Context.class);
transformation = (CursorTransformation) c.newInstance(mContext);
}
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException("Cannot instanciate transform type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + className, e);
} catch (NoSuchMethodException e) {
throw new IllegalArgumentException("Cannot instanciate transform type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + className, e);
} catch (InvocationTargetException e) {
throw new IllegalArgumentException("Cannot instanciate transform type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + className, e);
} catch (InstantiationException e) {
throw new IllegalArgumentException("Cannot instanciate transform type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + className, e);
} catch (IllegalAccessException e) {
throw new IllegalArgumentException("Cannot instanciate transform type in " +
mContext.getResources().getResourceEntryName(mId) + ": " + className, e);
}
}
a.recycle();
if (transformation == null) {
throw new IllegalArgumentException("A transform item in " +
resources.getResourceEntryName(mId) + " must have a 'withClass' or " +
"'withExpression' attribute");
}
return transformation;
}
private CursorTransformation createExpressionTransformation(String expression) {
return new ExpressionTransformation(mContext, expression);
}
}
/**
* Interface used by adapters that require to be loaded after creation.
*/
private static interface ManagedAdapter {
/**
* Loads the content of the adapter, asynchronously.
*/
void load();
}
/**
* Implementation of a Cursor adapter defined in XML. This class is a thin wrapper
* of a SimpleCursorAdapter. The main difference is the ability to handle CursorBinders.
*/
private static class XmlCursorAdapter extends SimpleCursorAdapter implements ManagedAdapter {
private Context mContext;
private String mUri;
private final String mSelection;
private final String[] mSelectionArgs;
private final String mSortOrder;
private final int[] mTo;
private final String[] mFrom;
private final String[] mColumns;
private final CursorBinder[] mBinders;
private AsyncTask<Void,Void,Cursor> mLoadTask;
XmlCursorAdapter(Context context, int layout, String uri, String[] from, int[] to,
String selection, String[] selectionArgs, String sortOrder,
HashMap<String, CursorBinder> binders) {
super(context, layout, null, from, to);
mContext = context;
mUri = uri;
mFrom = from;
mTo = to;
mSelection = selection;
mSelectionArgs = selectionArgs;
mSortOrder = sortOrder;
mColumns = new String[from.length + 1];
// This is mandatory in CursorAdapter
mColumns[0] = "_id";
System.arraycopy(from, 0, mColumns, 1, from.length);
CursorBinder basic = new StringBinder(context, new IdentityTransformation(context));
final int count = from.length;
mBinders = new CursorBinder[count];
for (int i = 0; i < count; i++) {
CursorBinder binder = binders.get(from[i]);
if (binder == null) binder = basic;
mBinders[i] = binder;
}
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
final int count = mTo.length;
final int[] to = mTo;
final CursorBinder[] binders = mBinders;
for (int i = 0; i < count; i++) {
final View v = view.findViewById(to[i]);
if (v != null) {
// Not optimal, the column index could be cached
binders[i].bind(v, cursor, cursor.getColumnIndex(mFrom[i]));
}
}
}
public void load() {
if (mUri != null) {
mLoadTask = new QueryTask().execute();
}
}
void setUri(String uri) {
mUri = uri;
}
@Override
public void changeCursor(Cursor c) {
if (mLoadTask != null && mLoadTask.getStatus() != QueryTask.Status.FINISHED) {
mLoadTask.cancel(true);
mLoadTask = null;
}
super.changeCursor(c);
}
class QueryTask extends AsyncTask<Void, Void, Cursor> {
@Override
protected Cursor doInBackground(Void... params) {
if (mContext instanceof Activity) {
return ((Activity) mContext).managedQuery(
Uri.parse(mUri), mColumns, mSelection, mSelectionArgs, mSortOrder);
} else {
return mContext.getContentResolver().query(
Uri.parse(mUri), mColumns, mSelection, mSelectionArgs, mSortOrder);
}
}
@Override
protected void onPostExecute(Cursor cursor) {
if (!isCancelled()) {
XmlCursorAdapter.super.changeCursor(cursor);
}
}
}
}
/**
* Identity transformation, returns the content of the specified column as a String,
* without performing any manipulation. This is used when no transformation is specified.
*/
private static class IdentityTransformation extends CursorTransformation {
public IdentityTransformation(Context context) {
super(context);
}
@Override
public String transform(Cursor cursor, int columnIndex) {
return cursor.getString(columnIndex);
}
}
/**
* An expression transformation is a simple template based replacement utility.
* In an expression, each segment of the form <code>{([^}]+)}</code> is replaced
* with the value of the column of name $1.
*/
private static class ExpressionTransformation extends CursorTransformation {
private final ExpressionNode mFirstNode = new ConstantExpressionNode("");
private final StringBuilder mBuilder = new StringBuilder();
public ExpressionTransformation(Context context, String expression) {
super(context);
parse(expression);
}
private void parse(String expression) {
ExpressionNode node = mFirstNode;
int segmentStart;
int count = expression.length();
for (int i = 0; i < count; i++) {
char c = expression.charAt(i);
// Start a column name segment
segmentStart = i;
if (c == '{') {
while (i < count && (c = expression.charAt(i)) != '}') {
i++;
}
// We've reached the end, but the expression didn't close
if (c != '}') {
throw new IllegalStateException("The transform expression contains a " +
"non-closed column name: " +
expression.substring(segmentStart + 1, i));
}
node.next = new ColumnExpressionNode(expression.substring(segmentStart + 1, i));
} else {
while (i < count && (c = expression.charAt(i)) != '{') {
i++;
}
node.next = new ConstantExpressionNode(expression.substring(segmentStart, i));
// Rewind if we've reached a column expression
if (c == '{') i--;
}
node = node.next;
}
}
@Override
public String transform(Cursor cursor, int columnIndex) {
final StringBuilder builder = mBuilder;
builder.delete(0, builder.length());
ExpressionNode node = mFirstNode;
// Skip the first node
while ((node = node.next) != null) {
builder.append(node.asString(cursor));
}
return builder.toString();
}
static abstract class ExpressionNode {
public ExpressionNode next;
public abstract String asString(Cursor cursor);
}
static class ConstantExpressionNode extends ExpressionNode {
private final String mConstant;
ConstantExpressionNode(String constant) {
mConstant = constant;
}
@Override
public String asString(Cursor cursor) {
return mConstant;
}
}
static class ColumnExpressionNode extends ExpressionNode {
private final String mColumnName;
private Cursor mSignature;
private int mColumnIndex = -1;
ColumnExpressionNode(String columnName) {
mColumnName = columnName;
}
@Override
public String asString(Cursor cursor) {
if (cursor != mSignature || mColumnIndex == -1) {
mColumnIndex = cursor.getColumnIndex(mColumnName);
mSignature = cursor;
}
return cursor.getString(mColumnIndex);
}
}
}
/**
* A map transformation offers a simple mapping between specified String values
* to Strings or integers.
*/
private static class MapTransformation extends CursorTransformation {
private final HashMap<String, String> mStringMappings;
private final HashMap<String, Integer> mResourceMappings;
public MapTransformation(Context context) {
super(context);
mStringMappings = new HashMap<String, String>();
mResourceMappings = new HashMap<String, Integer>();
}
void addStringMapping(String from, String to) {
mStringMappings.put(from, to);
}
void addResourceMapping(String from, int to) {
mResourceMappings.put(from, to);
}
@Override
public String transform(Cursor cursor, int columnIndex) {
final String value = cursor.getString(columnIndex);
final String transformed = mStringMappings.get(value);
return transformed == null ? value : transformed;
}
@Override
public int transformToResource(Cursor cursor, int columnIndex) {
final String value = cursor.getString(columnIndex);
final Integer transformed = mResourceMappings.get(value);
try {
return transformed == null ? Integer.parseInt(value) : transformed;
} catch (NumberFormatException e) {
return 0;
}
}
}
/**
* Binds a String to a TextView.
*/
private static class StringBinder extends CursorBinder {
public StringBinder(Context context, CursorTransformation transformation) {
super(context, transformation);
}
@Override
public boolean bind(View view, Cursor cursor, int columnIndex) {
if (view instanceof TextView) {
final String text = mTransformation.transform(cursor, columnIndex);
((TextView) view).setText(text);
return true;
}
return false;
}
}
/**
* Binds an image blob to an ImageView.
*/
private static class ImageBinder extends CursorBinder {
public ImageBinder(Context context, CursorTransformation transformation) {
super(context, transformation);
}
@Override
public boolean bind(View view, Cursor cursor, int columnIndex) {
if (view instanceof ImageView) {
final byte[] data = cursor.getBlob(columnIndex);
((ImageView) view).setImageBitmap(BitmapFactory.decodeByteArray(data, 0,
data.length));
return true;
}
return false;
}
}
private static class TagBinder extends CursorBinder {
public TagBinder(Context context, CursorTransformation transformation) {
super(context, transformation);
}
@Override
public boolean bind(View view, Cursor cursor, int columnIndex) {
final String text = mTransformation.transform(cursor, columnIndex);
view.setTag(text);
return true;
}
}
/**
* Binds an image URI to an ImageView.
*/
private static class ImageUriBinder extends CursorBinder {
public ImageUriBinder(Context context, CursorTransformation transformation) {
super(context, transformation);
}
@Override
public boolean bind(View view, Cursor cursor, int columnIndex) {
if (view instanceof ImageView) {
((ImageView) view).setImageURI(Uri.parse(
mTransformation.transform(cursor, columnIndex)));
return true;
}
return false;
}
}
/**
* Binds a drawable resource identifier to an ImageView.
*/
private static class DrawableBinder extends CursorBinder {
public DrawableBinder(Context context, CursorTransformation transformation) {
super(context, transformation);
}
@Override
public boolean bind(View view, Cursor cursor, int columnIndex) {
if (view instanceof ImageView) {
final int resource = mTransformation.transformToResource(cursor, columnIndex);
if (resource == 0) return false;
((ImageView) view).setImageResource(resource);
return true;
}
return false;
}
}
}