onDetachedFromWindow is called before onAttachedToWindow

Multiple threads are adding messages about the current
state of the views to the main looper. This can cause
onDetachedFromWindow to be posted on the looper before
onAttachedToWindow. This change will make sure to only
dispatch onDetachedFromWindow if we have previously
dispatched onAttachToWindow.

Change-Id: Ibc7cbcafb098bc000d2ef5480d2110d3fff4d55a

Author: Martin Wallgren

core/java/android/view/ViewRoot.java

@@ -176,6 +176,7 @@ public final class ViewRoot extends Handler implements ViewParent,
     private final Surface mSurface = new Surface();
 
     boolean mAdded;
+    private boolean mAttached;
     boolean mAddedTouchMode;
 
     /*package*/ int mAddNesting;
@@ -762,7 +763,10 @@ private void performTraversals() {
             attachInfo.mKeepScreenOn = false;
             viewVisibilityChanged = false;
             mLastConfiguration.setTo(host.getResources().getConfiguration());
-            host.dispatchAttachedToWindow(attachInfo, 0);
+            if (!mAttached) {
+                host.dispatchAttachedToWindow(attachInfo, 0);
+                mAttached = true;
+            }
             //Log.i(TAG, "Screen on initialized: " + attachInfo.mKeepScreenOn);
 
         } else {
@@ -1743,8 +1747,9 @@ public void recomputeViewAttributes(View child) {
     void dispatchDetachedFromWindow() {
         if (Config.LOGV) Log.v(TAG, "Detaching in " + this + " of " + mSurface);
 
-        if (mView != null) {
+        if (mView != null && mAttached) {
             mView.dispatchDetachedFromWindow();
+            mAttached = false;
         }
 
         mView = null;

core/tests/coretests/AndroidManifest.xml

@@ -96,6 +96,12 @@
 
     <application android:theme="@style/Theme">
         <uses-library android:name="android.test.runner" />
+        <activity android:name="android.view.ViewAttachTestActivity" android:label="View Attach Test">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.FRAMEWORK_INSTRUMENTATION_TEST" />
+            </intent-filter>
+        </activity>
         <activity android:name="StubTestBrowserActivity" android:label="Stubbed Test Browser">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>

core/tests/coretests/res/layout/attach_view_test.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent">
+    <android.view.ViewAttachView
+    android:id="@+id/view_attach_view"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:keepScreenOn="true"/>
+</LinearLayout>

core/tests/coretests/src/android/view/ViewAttachTest.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2011 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.pm.ActivityInfo;
+import android.os.SystemClock;
+import android.test.ActivityInstrumentationTestCase2;
+
+public class ViewAttachTest extends
+        ActivityInstrumentationTestCase2<ViewAttachTestActivity> {
+
+    public ViewAttachTest() {
+        super(ViewAttachTestActivity.class);
+    }
+
+    /**
+     * Make sure that onAttachedToWindow and onDetachedToWindow is called in the
+     * correct order The ViewAttachTestActivity contains a view that will throw
+     * an RuntimeException if onDetachedToWindow and onAttachedToWindow is
+     * called in the wrong order.
+     *
+     * 1. Initiate the activity 2. Perform a series of orientation changes to
+     * the activity (this will force the View hierarchy to be rebuild,
+     * generating onAttachedToWindow and onDetachedToWindow)
+     *
+     * Expected result: No RuntimeException is thrown from the TestView in
+     * ViewFlipperTestActivity.
+     *
+     * @throws Throwable
+     */
+    public void testAttached() throws Throwable {
+        final ViewAttachTestActivity activity = getActivity();
+        for (int i = 0; i < 20; i++) {
+            activity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
+            SystemClock.sleep(250);
+            activity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
+            SystemClock.sleep(250);
+        }
+    }
+}

core/tests/coretests/src/android/view/ViewAttachTestActivity.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2011 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 com.android.frameworks.coretests.R;
+
+import android.app.Activity;
+import android.os.Bundle;
+
+public class ViewAttachTestActivity extends Activity {
+    public static final String TAG = "OnAttachedTest";
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.attach_view_test);
+    }
+}

core/tests/coretests/src/android/view/ViewAttachView.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2011 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.graphics.Canvas;
+import android.graphics.Color;
+import android.os.SystemClock;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.View;
+
+/**
+ * A View that will throw a RuntimeException if onAttachedToWindow and
+ * onDetachedFromWindow is called in the wrong order for ViewAttachTest
+ */
+public class ViewAttachView extends View {
+    public static final String TAG = "OnAttachedTest";
+    private boolean attached;
+
+    public ViewAttachView(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        init(attrs, defStyle);
+    }
+
+    public ViewAttachView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        init(attrs, 0);
+    }
+
+    public ViewAttachView(Context context) {
+        super(context);
+        init(null, 0);
+    }
+
+    private void init(AttributeSet attrs, int defStyle) {
+        SystemClock.sleep(2000);
+    }
+
+    @Override
+    protected void onAttachedToWindow() {
+        Log.d(TAG, "onAttachedToWindow");
+        super.onAttachedToWindow();
+        if (attached) {
+            throw new RuntimeException("OnAttachedToWindow called more than once in a row");
+        }
+        attached = true;
+    }
+
+    @Override
+    protected void onDetachedFromWindow() {
+        Log.d(TAG, "onDetachedFromWindow");
+        super.onDetachedFromWindow();
+        if (!attached) {
+            throw new RuntimeException(
+                    "onDetachedFromWindowcalled without prior call to OnAttachedToWindow");
+        }
+        attached = false;
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+        canvas.drawColor(Color.BLUE);
+    }
+}