android - Android崩溃:回收ImageView然后再次启动Activity

Question

我有两个 Activity ，MainActvity和ImageActivity，我的步骤如下:

启动MainActivity

启动ImageActivity

单击backButton返回MainActivity

启动ImageActivity

然后应用崩溃。

我想原因是因为我回收了imageview，但是这没有任何意义。我不明白为什么它可以在第二个ImageActivity中调用崩溃。有人可以解释吗？ (我认为步骤2和步骤4创建了ImageActivity的新实例)

我的代码如下:

主要 Activity :

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.nextView).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startNewImageActivity();
            }
        });
    }

    public void startNewImageActivity(){
        Intent mIntent = new Intent();
        mIntent.setClass(MainActivity.this,ImageActivity.class);
        startActivity(mIntent);
    }

ImageActivity

public class ImageActivity extends Activity {
    private ImageView mView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.image_layout);
        mView =(ImageView) findViewById(R.id.detail_card_stroke_image);
    }

    @Override
    protected void onDestroy() {

        Log.i(ImageActivity.class.getName(),"onDestroy");
        if(null == mView){
            return ;
        }
        if(null != mView.getDrawable()){
            if(mView.getDrawable() instanceof BitmapDrawable) {
                if(null != ((BitmapDrawable) mView.getDrawable()).getBitmap())
                    ((BitmapDrawable) mView.getDrawable()).getBitmap().recycle();
                // mView.setImageBitmap(null);
            }
        }

        super.onDestroy();
    }
}

image_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/detail_card_stroke_image"
        android:layout_width="354dp"
        android:layout_height="234dp"
        android:layout_gravity="center_horizontal"
        android:scaleType="fitXY"
        android:src="@drawable/card_glow"
        android:layout_marginTop="10dp"
        android:alpha="1" />
</LinearLayout>

我的源代码在 github中

我的崩溃日志如下:

     11-18 11:36:13.860 21062-21062/com.looppay.android.tpd E/AndroidRuntime: FATAL EXCEPTION: main
                                                                     Process: com.looppay.android.tpd, PID: 21062
                                                                     java.lang.RuntimeException: Canvas: trying to use a recycled bitmap android.graphics.Bitmap@5c1dc07
                                                                         at android.graphics.Canvas.throwIfCannotDraw(Canvas.java:1301)
                                                                         at android.graphics.Canvas.drawBitmap(Canvas.java:1435)
                                                                         at android.graphics.drawable.BitmapDrawable.draw(BitmapDrawable.java:551)
                                                                         at android.widget.ImageView.onDraw(ImageView.java:1252)
                                                                         at android.view.View.draw(View.java:17469)
                                                                         at android.view.View.updateDisplayListIfDirty(View.java:16464)
                                                                         at android.view.View.draw(View.java:17238)
                                                                         at android.view.ViewGroup.drawChild(ViewGroup.java:3921)
                                                                         at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3711)
                                                                         at android.view.View.draw(View.java:17472)
                                                                         at android.view.View.updateDisplayListIfDirty(View.java:16464)
                                                                         at android.view.View.draw(View.java:17238)
                                                                         at android.view.ViewGroup.drawChild(ViewGroup.java:3921)
                                                                         at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3711)
                                                                         at android.view.View.updateDisplayListIfDirty(View.java:16459)
                                                                         at android.view.View.draw(View.java:17238)
                                                                         at android.view.ViewGroup.drawChild(ViewGroup.java:3921)
                                                                         at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3711)
                                                                         at android.view.View.draw(View.java:17472)
                                                                         at android.view.View.updateDisplayListIfDirty(View.java:16464)
                                                                         at android.view.View.draw(View.java:17238)
                                                                         at android.view.ViewGroup.drawChild(ViewGroup.java:3921)
                                                                         at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3711)
                                                                         at android.view.View.updateDisplayListIfDirty(View.java:16459)
                                                                         at android.view.View.draw(View.java:17238)
                                                                         at android.view.ViewGroup.drawChild(ViewGroup.java:3921)
                                                                         at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3711)
                                                                         at android.view.View.updateDisplayListIfDirty(View.java:16459)
                                                                         at android.view.View.draw(View.java:17238)
                                                                         at android.view.ViewGroup.drawChild(ViewGroup.java:3921)
                                                                         at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3711)
                                                                         at android.view.View.draw(View.java:17472)
                                                                         at com.android.internal.policy.PhoneWindow$DecorView.draw(PhoneWindow.java:3205)
                                                                         at android.view.View.updateDisplayListIfDirty(View.java:16464)
                                                                         at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:325)
                                                                         at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:331)
                                                                         at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:366)
                                                                         at android.view.ViewRootImpl.draw(ViewRootImpl.java:3140)
                                                                         at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2939)
                                                                         at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2522)
                                                                         at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1437)
                                                                         at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7414)
                                                                         at android.view.Choreographer$CallbackRecord.run(Choreographer.java:920)
                                                                         at android.view.Choreographer.doCallbacks(Choreographer.java:695)
                                                                         at android.view.Choreographer.doFrame(Choreographer.java:631)
                                                                         at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:906)
                                                                         at android.os.Handler.handleCallback(Handler.java:739)
                                                                         at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                         at android.os.Looper.loop(Looper.java:158)
                                                                         at android.app.ActivityThread.main(ActivityThread.java:7224)
                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

Answer 1

实际上，这是因为您回收了位图。

仅当确定在Android 3.0及更高版本上该位图没有更多用途时，才应调用recycle():位图已从内存中重用，并且当您调用recycle()时，已从内存中删除了该位图。

您可以从ImageView中删除android:src="@drawable/card_glow"，并从代码中添加位图:

Bitmap bitmap = ...;
if (bitmap != null && !bitmap.isRecycled())
    imageView.setImageBitmap(bitmap);

有关更多信息，请参见 Manage Memory。