core/java/android/view/ViewStub.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2008 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.view;

 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
 import android.util.AttributeSet;
 import android.widget.RemoteViews.RemoteView;

 import com.android.internal.R;

 import java.lang.ref.WeakReference;

 /**
  * A ViewStub is an invisible, zero-sized View that can be used to lazily inflate
  * layout resources at runtime.
  *
  * When a ViewStub is made visible, or when {@link #inflate()}  is invoked, the layout resource
  * is inflated. The ViewStub then replaces itself in its parent with the inflated View or Views.
  * Therefore, the ViewStub exists in the view hierarchy until {@link #setVisibility(int)} or
  * {@link #inflate()} is invoked.
  *
  * The inflated View is added to the ViewStub's parent with the ViewStub's layout
  * parameters. Similarly, you can define/override the inflate View's id by using the
  * ViewStub's inflatedId property. For instance:
  *
  * <pre>
  *     &lt;ViewStub android:id="@+id/stub"
  *               android:inflatedId="@+id/subTree"
  *               android:layout="@layout/mySubTree"
  *               android:layout_width="120dip"
  *               android:layout_height="40dip" /&gt;
  * </pre>
  *
  * The ViewStub thus defined can be found using the id "stub." After inflation of
  * the layout resource "mySubTree," the ViewStub is removed from its parent. The
  * View created by inflating the layout resource "mySubTree" can be found using the
  * id "subTree," specified by the inflatedId property. The inflated View is finally
  * assigned a width of 120dip and a height of 40dip.
  *
  * The preferred way to perform the inflation of the layout resource is the following:
  *
  * <pre>
  *     ViewStub stub = (ViewStub) findViewById(R.id.stub);
  *     View inflated = stub.inflate();
  * </pre>
  *
  * When {@link #inflate()} is invoked, the ViewStub is replaced by the inflated View
  * and the inflated View is returned. This lets applications get a reference to the
  * inflated View without executing an extra findViewById().
  *
  * @attr ref android.R.styleable#ViewStub_inflatedId
  * @attr ref android.R.styleable#ViewStub_layout
  */
 @RemoteView
 public final class ViewStub extends View {
     private int mLayoutResource = 0;
     private int mInflatedId;

     private WeakReference<View> mInflatedViewRef;

     private LayoutInflater mInflater;
     private OnInflateListener mInflateListener;

     public ViewStub(Context context) {
         initialize(context);
     }

     /**
      * Creates a new ViewStub with the specified layout resource.
      *
      * @param context The application's environment.
      * @param layoutResource The reference to a layout resource that will be inflated.
      */
     public ViewStub(Context context, int layoutResource) {
         mLayoutResource = layoutResource;
         initialize(context);
     }

     public ViewStub(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
     }

     @SuppressWarnings({"UnusedDeclaration"})
     public ViewStub(Context context, AttributeSet attrs, int defStyle) {
         TypedArray a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.ViewStub,
                 defStyle, 0);

         mInflatedId = a.getResourceId(R.styleable.ViewStub_inflatedId, NO_ID);
         mLayoutResource = a.getResourceId(R.styleable.ViewStub_layout, 0);

         a.recycle();

         a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.View, defStyle, 0);
         mID = a.getResourceId(R.styleable.View_id, NO_ID);
         a.recycle();

         initialize(context);
     }

     private void initialize(Context context) {
         mContext = context;
         setVisibility(GONE);
         setWillNotDraw(true);
     }

     /**
      * Returns the id taken by the inflated view. If the inflated id is
      * {@link View#NO_ID}, the inflated view keeps its original id.
      *
      * @return A positive integer used to identify the inflated view or
      *         {@link #NO_ID} if the inflated view should keep its id.
      *
      * @see #setInflatedId(int)
      * @attr ref android.R.styleable#ViewStub_inflatedId
      */
     public int getInflatedId() {
         return mInflatedId;
     }

     /**
      * Defines the id taken by the inflated view. If the inflated id is
      * {@link View#NO_ID}, the inflated view keeps its original id.
      *
      * @param inflatedId A positive integer used to identify the inflated view or
      *                   {@link #NO_ID} if the inflated view should keep its id.
      *
      * @see #getInflatedId()
      * @attr ref android.R.styleable#ViewStub_inflatedId
      */
     @android.view.RemotableViewMethod
     public void setInflatedId(int inflatedId) {
         mInflatedId = inflatedId;
     }

     /**
      * Returns the layout resource that will be used by {@link #setVisibility(int)} or
      * {@link #inflate()} to replace this StubbedView
      * in its parent by another view.
      *
      * @return The layout resource identifier used to inflate the new View.
      *
      * @see #setLayoutResource(int)
      * @see #setVisibility(int)
      * @see #inflate()
      * @attr ref android.R.styleable#ViewStub_layout
      */
     public int getLayoutResource() {
         return mLayoutResource;
     }

     /**
      * Specifies the layout resource to inflate when this StubbedView becomes visible or invisible
      * or when {@link #inflate()} is invoked. The View created by inflating the layout resource is
      * used to replace this StubbedView in its parent.
      *
      * @param layoutResource A valid layout resource identifier (different from 0.)
      *
      * @see #getLayoutResource()
      * @see #setVisibility(int)
      * @see #inflate()
      * @attr ref android.R.styleable#ViewStub_layout
      */
     @android.view.RemotableViewMethod
     public void setLayoutResource(int layoutResource) {
         mLayoutResource = layoutResource;
     }

     /**
      * Set {@link LayoutInflater} to use in {@link #inflate()}, or {@code null}
      * to use the default.
      */
     public void setLayoutInflater(LayoutInflater inflater) {
         mInflater = inflater;
     }

     /**
      * Get current {@link LayoutInflater} used in {@link #inflate()}.
      */
     public LayoutInflater getLayoutInflater() {
         return mInflater;
     }

     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         setMeasuredDimension(0, 0);
     }

     @Override
     public void draw(Canvas canvas) {
     }

     @Override
     protected void dispatchDraw(Canvas canvas) {
     }

     /**
      * When visibility is set to {@link #VISIBLE} or {@link #INVISIBLE},
      * {@link #inflate()} is invoked and this StubbedView is replaced in its parent
      * by the inflated layout resource.
      *
      * @param visibility One of {@link #VISIBLE}, {@link #INVISIBLE}, or {@link #GONE}.
      *
      * @see #inflate()
      */
     @Override
     @android.view.RemotableViewMethod
     public void setVisibility(int visibility) {
         if (mInflatedViewRef != null) {
             View view = mInflatedViewRef.get();
             if (view != null) {
                 view.setVisibility(visibility);
             } else {
                 throw new IllegalStateException("setVisibility called on un-referenced view");
             }
         } else {
             super.setVisibility(visibility);
             if (visibility == VISIBLE || visibility == INVISIBLE) {
                 inflate();
             }
         }
     }

     /**
      * Inflates the layout resource identified by {@link #getLayoutResource()}
      * and replaces this StubbedView in its parent by the inflated layout resource.
      *
      * @return The inflated layout resource.
      *
      */
     public View inflate() {
         final ViewParent viewParent = getParent();

         if (viewParent != null && viewParent instanceof ViewGroup) {
             if (mLayoutResource != 0) {
                 final ViewGroup parent = (ViewGroup) viewParent;
                 final LayoutInflater factory;
                 if (mInflater != null) {
                     factory = mInflater;
                 } else {
                     factory = LayoutInflater.from(mContext);
                 }
                 final View view = factory.inflate(mLayoutResource, parent,
                         false);

                 if (mInflatedId != NO_ID) {
                     view.setId(mInflatedId);
                 }

                 final int index = parent.indexOfChild(this);
                 parent.removeViewInLayout(this);

                 final ViewGroup.LayoutParams layoutParams = getLayoutParams();
                 if (layoutParams != null) {
                     parent.addView(view, index, layoutParams);
                 } else {
                     parent.addView(view, index);
                 }

                 mInflatedViewRef = new WeakReference<View>(view);

                 if (mInflateListener != null) {
                     mInflateListener.onInflate(this, view);
                 }

                 return view;
             } else {
                 throw new IllegalArgumentException("ViewStub must have a valid layoutResource");
             }
         } else {
             throw new IllegalStateException("ViewStub must have a non-null ViewGroup viewParent");
         }
     }

     /**
      * Specifies the inflate listener to be notified after this ViewStub successfully
      * inflated its layout resource.
      *
      * @param inflateListener The OnInflateListener to notify of successful inflation.
      *
      * @see android.view.ViewStub.OnInflateListener
      */
     public void setOnInflateListener(OnInflateListener inflateListener) {
         mInflateListener = inflateListener;
     }

     /**
      * Listener used to receive a notification after a ViewStub has successfully
      * inflated its layout resource.
      *
      * @see android.view.ViewStub#setOnInflateListener(android.view.ViewStub.OnInflateListener)
      */
     public static interface OnInflateListener {
         /**
          * Invoked after a ViewStub successfully inflated its layout resource.
          * This method is invoked after the inflated view was added to the
          * hierarchy but before the layout pass.
          *
          * @param stub The ViewStub that initiated the inflation.
          * @param inflated The inflated View.
          */
         void onInflate(ViewStub stub, View inflated);
     }
 }
	/*
	* Copyright (C) 2008 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.view;

	import android.content.Context;
	import android.content.res.TypedArray;
	import android.graphics.Canvas;
	import android.util.AttributeSet;
	import android.widget.RemoteViews.RemoteView;

	import com.android.internal.R;

	import java.lang.ref.WeakReference;

	/**
	* A ViewStub is an invisible, zero-sized View that can be used to lazily inflate
	* layout resources at runtime.
	*
	* When a ViewStub is made visible, or when {@link #inflate()} is invoked, the layout resource
	* is inflated. The ViewStub then replaces itself in its parent with the inflated View or Views.
	* Therefore, the ViewStub exists in the view hierarchy until {@link #setVisibility(int)} or
	* {@link #inflate()} is invoked.
	*
	* The inflated View is added to the ViewStub's parent with the ViewStub's layout
	* parameters. Similarly, you can define/override the inflate View's id by using the
	* ViewStub's inflatedId property. For instance:
	*
	* <pre>
	* <ViewStub android:id="@+id/stub"
	* android:inflatedId="@+id/subTree"
	* android:layout="@layout/mySubTree"
	* android:layout_width="120dip"
	* android:layout_height="40dip" />
	* </pre>
	*
	* The ViewStub thus defined can be found using the id "stub." After inflation of
	* the layout resource "mySubTree," the ViewStub is removed from its parent. The
	* View created by inflating the layout resource "mySubTree" can be found using the
	* id "subTree," specified by the inflatedId property. The inflated View is finally
	* assigned a width of 120dip and a height of 40dip.
	*
	* The preferred way to perform the inflation of the layout resource is the following:
	*
	* <pre>
	* ViewStub stub = (ViewStub) findViewById(R.id.stub);
	* View inflated = stub.inflate();
	* </pre>
	*
	* When {@link #inflate()} is invoked, the ViewStub is replaced by the inflated View
	* and the inflated View is returned. This lets applications get a reference to the
	* inflated View without executing an extra findViewById().
	*
	* @attr ref android.R.styleable#ViewStub_inflatedId
	* @attr ref android.R.styleable#ViewStub_layout
	*/
	@RemoteView
	public final class ViewStub extends View {
	private int mLayoutResource = 0;
	private int mInflatedId;

	private WeakReference<View> mInflatedViewRef;

	private LayoutInflater mInflater;
	private OnInflateListener mInflateListener;

	public ViewStub(Context context) {
	initialize(context);
	}

	/**
	* Creates a new ViewStub with the specified layout resource.
	*
	* @param context The application's environment.
	* @param layoutResource The reference to a layout resource that will be inflated.
	*/
	public ViewStub(Context context, int layoutResource) {
	mLayoutResource = layoutResource;
	initialize(context);
	}

	public ViewStub(Context context, AttributeSet attrs) {
	this(context, attrs, 0);
	}

	@SuppressWarnings({"UnusedDeclaration"})
	public ViewStub(Context context, AttributeSet attrs, int defStyle) {
	TypedArray a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.ViewStub,
	defStyle, 0);

	mInflatedId = a.getResourceId(R.styleable.ViewStub_inflatedId, NO_ID);
	mLayoutResource = a.getResourceId(R.styleable.ViewStub_layout, 0);

	a.recycle();

	a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.View, defStyle, 0);
	mID = a.getResourceId(R.styleable.View_id, NO_ID);
	a.recycle();

	initialize(context);
	}

	private void initialize(Context context) {
	mContext = context;
	setVisibility(GONE);
	setWillNotDraw(true);
	}

	/**
	* Returns the id taken by the inflated view. If the inflated id is
	* {@link View#NO_ID}, the inflated view keeps its original id.
	*
	* @return A positive integer used to identify the inflated view or
	* {@link #NO_ID} if the inflated view should keep its id.
	*
	* @see #setInflatedId(int)
	* @attr ref android.R.styleable#ViewStub_inflatedId
	*/
	public int getInflatedId() {
	return mInflatedId;
	}

	/**
	* Defines the id taken by the inflated view. If the inflated id is
	* {@link View#NO_ID}, the inflated view keeps its original id.
	*
	* @param inflatedId A positive integer used to identify the inflated view or
	* {@link #NO_ID} if the inflated view should keep its id.
	*
	* @see #getInflatedId()
	* @attr ref android.R.styleable#ViewStub_inflatedId
	*/
	@android.view.RemotableViewMethod
	public void setInflatedId(int inflatedId) {
	mInflatedId = inflatedId;
	}

	/**
	* Returns the layout resource that will be used by {@link #setVisibility(int)} or
	* {@link #inflate()} to replace this StubbedView
	* in its parent by another view.
	*
	* @return The layout resource identifier used to inflate the new View.
	*
	* @see #setLayoutResource(int)
	* @see #setVisibility(int)
	* @see #inflate()
	* @attr ref android.R.styleable#ViewStub_layout
	*/
	public int getLayoutResource() {
	return mLayoutResource;
	}

	/**
	* Specifies the layout resource to inflate when this StubbedView becomes visible or invisible
	* or when {@link #inflate()} is invoked. The View created by inflating the layout resource is
	* used to replace this StubbedView in its parent.
	*
	* @param layoutResource A valid layout resource identifier (different from 0.)
	*
	* @see #getLayoutResource()
	* @see #setVisibility(int)
	* @see #inflate()
	* @attr ref android.R.styleable#ViewStub_layout
	*/
	@android.view.RemotableViewMethod
	public void setLayoutResource(int layoutResource) {
	mLayoutResource = layoutResource;
	}

	/**
	* Set {@link LayoutInflater} to use in {@link #inflate()}, or {@code null}
	* to use the default.
	*/
	public void setLayoutInflater(LayoutInflater inflater) {
	mInflater = inflater;
	}

	/**
	* Get current {@link LayoutInflater} used in {@link #inflate()}.
	*/
	public LayoutInflater getLayoutInflater() {
	return mInflater;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
	setMeasuredDimension(0, 0);
	}

	@Override
	public void draw(Canvas canvas) {
	}

	@Override
	protected void dispatchDraw(Canvas canvas) {
	}

	/**
	* When visibility is set to {@link #VISIBLE} or {@link #INVISIBLE},
	* {@link #inflate()} is invoked and this StubbedView is replaced in its parent
	* by the inflated layout resource.
	*
	* @param visibility One of {@link #VISIBLE}, {@link #INVISIBLE}, or {@link #GONE}.
	*
	* @see #inflate()
	*/
	@Override
	@android.view.RemotableViewMethod
	public void setVisibility(int visibility) {
	if (mInflatedViewRef != null) {
	View view = mInflatedViewRef.get();
	if (view != null) {
	view.setVisibility(visibility);
	} else {
	throw new IllegalStateException("setVisibility called on un-referenced view");
	}
	} else {
	super.setVisibility(visibility);
	if (visibility == VISIBLE \|\| visibility == INVISIBLE) {
	inflate();
	}
	}
	}

	/**
	* Inflates the layout resource identified by {@link #getLayoutResource()}
	* and replaces this StubbedView in its parent by the inflated layout resource.
	*
	* @return The inflated layout resource.
	*
	*/
	public View inflate() {
	final ViewParent viewParent = getParent();

	if (viewParent != null && viewParent instanceof ViewGroup) {
	if (mLayoutResource != 0) {
	final ViewGroup parent = (ViewGroup) viewParent;
	final LayoutInflater factory;
	if (mInflater != null) {
	factory = mInflater;
	} else {
	factory = LayoutInflater.from(mContext);
	}
	final View view = factory.inflate(mLayoutResource, parent,
	false);

	if (mInflatedId != NO_ID) {
	view.setId(mInflatedId);
	}

	final int index = parent.indexOfChild(this);
	parent.removeViewInLayout(this);

	final ViewGroup.LayoutParams layoutParams = getLayoutParams();
	if (layoutParams != null) {
	parent.addView(view, index, layoutParams);
	} else {
	parent.addView(view, index);
	}

	mInflatedViewRef = new WeakReference<View>(view);

	if (mInflateListener != null) {
	mInflateListener.onInflate(this, view);
	}

	return view;
	} else {
	throw new IllegalArgumentException("ViewStub must have a valid layoutResource");
	}
	} else {
	throw new IllegalStateException("ViewStub must have a non-null ViewGroup viewParent");
	}
	}

	/**
	* Specifies the inflate listener to be notified after this ViewStub successfully
	* inflated its layout resource.
	*
	* @param inflateListener The OnInflateListener to notify of successful inflation.
	*
	* @see android.view.ViewStub.OnInflateListener
	*/
	public void setOnInflateListener(OnInflateListener inflateListener) {
	mInflateListener = inflateListener;
	}

	/**
	* Listener used to receive a notification after a ViewStub has successfully
	* inflated its layout resource.
	*
	* @see android.view.ViewStub#setOnInflateListener(android.view.ViewStub.OnInflateListener)
	*/
	public static interface OnInflateListener {
	/**
	* Invoked after a ViewStub successfully inflated its layout resource.
	* This method is invoked after the inflated view was added to the
	* hierarchy but before the layout pass.
	*
	* @param stub The ViewStub that initiated the inflation.
	* @param inflated The inflated View.
	*/
	void onInflate(ViewStub stub, View inflated);
	}
	}