| /* |
| * Copyright (C) 2006 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 android.widget; |
| |
| import android.annotation.WorkerThread; |
| import android.compat.annotation.UnsupportedAppUsage; |
| import android.content.Context; |
| import android.content.res.Resources; |
| import android.database.ContentObserver; |
| import android.database.Cursor; |
| import android.database.DataSetObserver; |
| import android.os.Handler; |
| import android.util.Log; |
| import android.view.ContextThemeWrapper; |
| import android.view.View; |
| import android.view.ViewGroup; |
| |
| /** |
| * Adapter that exposes data from a {@link android.database.Cursor Cursor} to a |
| * {@link android.widget.ListView ListView} widget. |
| * <p> |
| * The Cursor must include a column named "_id" or this class will not work. |
| * Additionally, using {@link android.database.MergeCursor} with this class will |
| * not work if the merged Cursors have overlapping values in their "_id" |
| * columns. |
| */ |
| public abstract class CursorAdapter extends BaseAdapter implements Filterable, |
| CursorFilter.CursorFilterClient, ThemedSpinnerAdapter { |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| @UnsupportedAppUsage |
| protected boolean mDataValid; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| protected boolean mAutoRequery; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| @UnsupportedAppUsage |
| protected Cursor mCursor; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| @UnsupportedAppUsage |
| protected Context mContext; |
| /** |
| * Context used for {@link #getDropDownView(int, View, ViewGroup)}. |
| * {@hide} |
| */ |
| protected Context mDropDownContext; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| @UnsupportedAppUsage |
| protected int mRowIDColumn; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| @UnsupportedAppUsage |
| protected ChangeObserver mChangeObserver; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| @UnsupportedAppUsage |
| protected DataSetObserver mDataSetObserver; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| protected CursorFilter mCursorFilter; |
| /** |
| * This field should be made private, so it is hidden from the SDK. |
| * {@hide} |
| */ |
| protected FilterQueryProvider mFilterQueryProvider; |
| |
| /** |
| * If set the adapter will call requery() on the cursor whenever a content change |
| * notification is delivered. Implies {@link #FLAG_REGISTER_CONTENT_OBSERVER}. |
| * |
| * @deprecated This option is discouraged, as it results in Cursor queries |
| * being performed on the application's UI thread and thus can cause poor |
| * responsiveness or even Application Not Responding errors. As an alternative, |
| * use {@link android.app.LoaderManager} with a {@link android.content.CursorLoader}. |
| */ |
| @Deprecated |
| public static final int FLAG_AUTO_REQUERY = 0x01; |
| |
| /** |
| * If set the adapter will register a content observer on the cursor and will call |
| * {@link #onContentChanged()} when a notification comes in. Be careful when |
| * using this flag: you will need to unset the current Cursor from the adapter |
| * to avoid leaks due to its registered observers. This flag is not needed |
| * when using a CursorAdapter with a |
| * {@link android.content.CursorLoader}. |
| */ |
| public static final int FLAG_REGISTER_CONTENT_OBSERVER = 0x02; |
| |
| /** |
| * Constructor that always enables auto-requery. |
| * |
| * @deprecated This option is discouraged, as it results in Cursor queries |
| * being performed on the application's UI thread and thus can cause poor |
| * responsiveness or even Application Not Responding errors. As an alternative, |
| * use {@link android.app.LoaderManager} with a {@link android.content.CursorLoader}. |
| * |
| * @param c The cursor from which to get the data. |
| * @param context The context |
| */ |
| @Deprecated |
| public CursorAdapter(Context context, Cursor c) { |
| init(context, c, FLAG_AUTO_REQUERY); |
| } |
| |
| /** |
| * Constructor that allows control over auto-requery. It is recommended |
| * you not use this, but instead {@link #CursorAdapter(Context, Cursor, int)}. |
| * When using this constructor, {@link #FLAG_REGISTER_CONTENT_OBSERVER} |
| * will always be set. |
| * |
| * @param c The cursor from which to get the data. |
| * @param context The context |
| * @param autoRequery If true the adapter will call requery() on the |
| * cursor whenever it changes so the most recent |
| * data is always displayed. Using true here is discouraged. |
| */ |
| public CursorAdapter(Context context, Cursor c, boolean autoRequery) { |
| init(context, c, autoRequery ? FLAG_AUTO_REQUERY : FLAG_REGISTER_CONTENT_OBSERVER); |
| } |
| |
| /** |
| * Recommended constructor. |
| * |
| * @param c The cursor from which to get the data. |
| * @param context The context |
| * @param flags Flags used to determine the behavior of the adapter; may |
| * be any combination of {@link #FLAG_AUTO_REQUERY} and |
| * {@link #FLAG_REGISTER_CONTENT_OBSERVER}. |
| */ |
| public CursorAdapter(Context context, Cursor c, int flags) { |
| init(context, c, flags); |
| } |
| |
| /** |
| * @deprecated Don't use this, use the normal constructor. This will |
| * be removed in the future. |
| */ |
| @Deprecated |
| protected void init(Context context, Cursor c, boolean autoRequery) { |
| init(context, c, autoRequery ? FLAG_AUTO_REQUERY : FLAG_REGISTER_CONTENT_OBSERVER); |
| } |
| |
| void init(Context context, Cursor c, int flags) { |
| if ((flags & FLAG_AUTO_REQUERY) == FLAG_AUTO_REQUERY) { |
| flags |= FLAG_REGISTER_CONTENT_OBSERVER; |
| mAutoRequery = true; |
| } else { |
| mAutoRequery = false; |
| } |
| boolean cursorPresent = c != null; |
| mCursor = c; |
| mDataValid = cursorPresent; |
| mContext = context; |
| mRowIDColumn = cursorPresent ? c.getColumnIndexOrThrow("_id") : -1; |
| if ((flags & FLAG_REGISTER_CONTENT_OBSERVER) == FLAG_REGISTER_CONTENT_OBSERVER) { |
| mChangeObserver = new ChangeObserver(); |
| mDataSetObserver = new MyDataSetObserver(); |
| } else { |
| mChangeObserver = null; |
| mDataSetObserver = null; |
| } |
| |
| if (cursorPresent) { |
| if (mChangeObserver != null) c.registerContentObserver(mChangeObserver); |
| if (mDataSetObserver != null) c.registerDataSetObserver(mDataSetObserver); |
| } |
| } |
| |
| /** |
| * Sets the {@link Resources.Theme} against which drop-down views are |
| * inflated. |
| * <p> |
| * By default, drop-down views are inflated against the theme of the |
| * {@link Context} passed to the adapter's constructor. |
| * |
| * @param theme the theme against which to inflate drop-down views or |
| * {@code null} to use the theme from the adapter's context |
| * @see #newDropDownView(Context, Cursor, ViewGroup) |
| */ |
| @Override |
| public void setDropDownViewTheme(Resources.Theme theme) { |
| if (theme == null) { |
| mDropDownContext = null; |
| } else if (theme == mContext.getTheme()) { |
| mDropDownContext = mContext; |
| } else { |
| mDropDownContext = new ContextThemeWrapper(mContext, theme); |
| } |
| } |
| |
| @Override |
| public Resources.Theme getDropDownViewTheme() { |
| return mDropDownContext == null ? null : mDropDownContext.getTheme(); |
| } |
| |
| /** |
| * Returns the cursor. |
| * @return the cursor. |
| */ |
| public Cursor getCursor() { |
| return mCursor; |
| } |
| |
| /** |
| * @see android.widget.ListAdapter#getCount() |
| */ |
| public int getCount() { |
| if (mDataValid && mCursor != null) { |
| return mCursor.getCount(); |
| } else { |
| return 0; |
| } |
| } |
| |
| /** |
| * @see android.widget.ListAdapter#getItem(int) |
| */ |
| public Object getItem(int position) { |
| if (mDataValid && mCursor != null) { |
| mCursor.moveToPosition(position); |
| return mCursor; |
| } else { |
| return null; |
| } |
| } |
| |
| /** |
| * @see android.widget.ListAdapter#getItemId(int) |
| */ |
| public long getItemId(int position) { |
| if (mDataValid && mCursor != null) { |
| if (mCursor.moveToPosition(position)) { |
| return mCursor.getLong(mRowIDColumn); |
| } else { |
| return 0; |
| } |
| } else { |
| return 0; |
| } |
| } |
| |
| @Override |
| public boolean hasStableIds() { |
| return true; |
| } |
| |
| /** |
| * @see android.widget.ListAdapter#getView(int, View, ViewGroup) |
| */ |
| public View getView(int position, View convertView, ViewGroup parent) { |
| if (!mDataValid) { |
| throw new IllegalStateException("this should only be called when the cursor is valid"); |
| } |
| if (!mCursor.moveToPosition(position)) { |
| throw new IllegalStateException("couldn't move cursor to position " + position); |
| } |
| View v; |
| if (convertView == null) { |
| v = newView(mContext, mCursor, parent); |
| } else { |
| v = convertView; |
| } |
| bindView(v, mContext, mCursor); |
| return v; |
| } |
| |
| @Override |
| public View getDropDownView(int position, View convertView, ViewGroup parent) { |
| if (mDataValid) { |
| final Context context = mDropDownContext == null ? mContext : mDropDownContext; |
| mCursor.moveToPosition(position); |
| final View v; |
| if (convertView == null) { |
| v = newDropDownView(context, mCursor, parent); |
| } else { |
| v = convertView; |
| } |
| bindView(v, context, mCursor); |
| return v; |
| } else { |
| return null; |
| } |
| } |
| |
| /** |
| * Makes a new view to hold the data pointed to by cursor. |
| * @param context Interface to application's global information |
| * @param cursor The cursor from which to get the data. The cursor is already |
| * moved to the correct position. |
| * @param parent The parent to which the new view is attached to |
| * @return the newly created view. |
| */ |
| public abstract View newView(Context context, Cursor cursor, ViewGroup parent); |
| |
| /** |
| * Makes a new drop down view to hold the data pointed to by cursor. |
| * @param context Interface to application's global information |
| * @param cursor The cursor from which to get the data. The cursor is already |
| * moved to the correct position. |
| * @param parent The parent to which the new view is attached to |
| * @return the newly created view. |
| */ |
| public View newDropDownView(Context context, Cursor cursor, ViewGroup parent) { |
| return newView(context, cursor, parent); |
| } |
| |
| /** |
| * Bind an existing view to the data pointed to by cursor |
| * @param view Existing view, returned earlier by newView |
| * @param context Interface to application's global information |
| * @param cursor The cursor from which to get the data. The cursor is already |
| * moved to the correct position. |
| */ |
| public abstract void bindView(View view, Context context, Cursor cursor); |
| |
| /** |
| * Change the underlying cursor to a new cursor. If there is an existing cursor it will be |
| * closed. |
| * |
| * @param cursor The new cursor to be used |
| */ |
| public void changeCursor(Cursor cursor) { |
| Cursor old = swapCursor(cursor); |
| if (old != null) { |
| old.close(); |
| } |
| } |
| |
| /** |
| * Swap in a new Cursor, returning the old Cursor. Unlike |
| * {@link #changeCursor(Cursor)}, the returned old Cursor is <em>not</em> |
| * closed. |
| * |
| * @param newCursor The new cursor to be used. |
| * @return Returns the previously set Cursor, or null if there was not one. |
| * If the given new Cursor is the same instance is the previously set |
| * Cursor, null is also returned. |
| */ |
| public Cursor swapCursor(Cursor newCursor) { |
| if (newCursor == mCursor) { |
| return null; |
| } |
| Cursor oldCursor = mCursor; |
| if (oldCursor != null) { |
| if (mChangeObserver != null) oldCursor.unregisterContentObserver(mChangeObserver); |
| if (mDataSetObserver != null) oldCursor.unregisterDataSetObserver(mDataSetObserver); |
| } |
| mCursor = newCursor; |
| if (newCursor != null) { |
| if (mChangeObserver != null) newCursor.registerContentObserver(mChangeObserver); |
| if (mDataSetObserver != null) newCursor.registerDataSetObserver(mDataSetObserver); |
| mRowIDColumn = newCursor.getColumnIndexOrThrow("_id"); |
| mDataValid = true; |
| // notify the observers about the new cursor |
| notifyDataSetChanged(); |
| } else { |
| mRowIDColumn = -1; |
| mDataValid = false; |
| // notify the observers about the lack of a data set |
| notifyDataSetInvalidated(); |
| } |
| return oldCursor; |
| } |
| |
| /** |
| * <p>Converts the cursor into a CharSequence. Subclasses should override this |
| * method to convert their results. The default implementation returns an |
| * empty String for null values or the default String representation of |
| * the value.</p> |
| * |
| * @param cursor the cursor to convert to a CharSequence |
| * @return a CharSequence representing the value |
| */ |
| public CharSequence convertToString(Cursor cursor) { |
| return cursor == null ? "" : cursor.toString(); |
| } |
| |
| /** |
| * Runs a query with the specified constraint. This query is requested |
| * by the filter attached to this adapter. |
| * |
| * The query is provided by a |
| * {@link android.widget.FilterQueryProvider}. |
| * If no provider is specified, the current cursor is not filtered and returned. |
| * |
| * After this method returns the resulting cursor is passed to {@link #changeCursor(Cursor)} |
| * and the previous cursor is closed. |
| * |
| * This method is always executed on a background thread, not on the |
| * application's main thread (or UI thread.) |
| * |
| * Contract: when constraint is null or empty, the original results, |
| * prior to any filtering, must be returned. |
| * |
| * @param constraint the constraint with which the query must be filtered |
| * |
| * @return a Cursor representing the results of the new query |
| * |
| * @see #getFilter() |
| * @see #getFilterQueryProvider() |
| * @see #setFilterQueryProvider(android.widget.FilterQueryProvider) |
| */ |
| @WorkerThread |
| public Cursor runQueryOnBackgroundThread(CharSequence constraint) { |
| if (mFilterQueryProvider != null) { |
| return mFilterQueryProvider.runQuery(constraint); |
| } |
| |
| return mCursor; |
| } |
| |
| public Filter getFilter() { |
| if (mCursorFilter == null) { |
| mCursorFilter = new CursorFilter(this); |
| } |
| return mCursorFilter; |
| } |
| |
| /** |
| * Returns the query filter provider used for filtering. When the |
| * provider is null, no filtering occurs. |
| * |
| * @return the current filter query provider or null if it does not exist |
| * |
| * @see #setFilterQueryProvider(android.widget.FilterQueryProvider) |
| * @see #runQueryOnBackgroundThread(CharSequence) |
| */ |
| public FilterQueryProvider getFilterQueryProvider() { |
| return mFilterQueryProvider; |
| } |
| |
| /** |
| * Sets the query filter provider used to filter the current Cursor. |
| * The provider's |
| * {@link android.widget.FilterQueryProvider#runQuery(CharSequence)} |
| * method is invoked when filtering is requested by a client of |
| * this adapter. |
| * |
| * @param filterQueryProvider the filter query provider or null to remove it |
| * |
| * @see #getFilterQueryProvider() |
| * @see #runQueryOnBackgroundThread(CharSequence) |
| */ |
| public void setFilterQueryProvider(FilterQueryProvider filterQueryProvider) { |
| mFilterQueryProvider = filterQueryProvider; |
| } |
| |
| /** |
| * Called when the {@link ContentObserver} on the cursor receives a change notification. |
| * The default implementation provides the auto-requery logic, but may be overridden by |
| * sub classes. |
| * |
| * @see ContentObserver#onChange(boolean) |
| */ |
| protected void onContentChanged() { |
| if (mAutoRequery && mCursor != null && !mCursor.isClosed()) { |
| if (false) Log.v("Cursor", "Auto requerying " + mCursor + " due to update"); |
| mDataValid = mCursor.requery(); |
| } |
| } |
| |
| private class ChangeObserver extends ContentObserver { |
| public ChangeObserver() { |
| super(new Handler()); |
| } |
| |
| @Override |
| public boolean deliverSelfNotifications() { |
| return true; |
| } |
| |
| @Override |
| public void onChange(boolean selfChange) { |
| onContentChanged(); |
| } |
| } |
| |
| private class MyDataSetObserver extends DataSetObserver { |
| @Override |
| public void onChanged() { |
| mDataValid = true; |
| notifyDataSetChanged(); |
| } |
| |
| @Override |
| public void onInvalidated() { |
| mDataValid = false; |
| notifyDataSetInvalidated(); |
| } |
| } |
| |
| } |