我有一个对话框，用户可以在其中自由地在对话框内绘图。

对话框正在扩展 View ，绘图区由

bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);

但是，绘图不需要保留，当用户关闭对话框并再次打开时，不需要保留他之前的绘图并从null重新绘制。

详细代码:

涂鸦 View :

   // DoodleView constructor initializes the DoodleView
   public DoodleView(Context context, AttributeSet attrs) 
   {
      super(context, attrs); // pass context to View's constructor

      paintScreen = new Paint(); // used to display bitmap onto screen

      // set the initial display settings for the painted line
      paintLine = new Paint();
      paintLine.setAntiAlias(true); // smooth edges of drawn line
      paintLine.setColor(Color.BLACK); // default color is black
      paintLine.setStyle(Paint.Style.STROKE); // solid line
      paintLine.setStrokeWidth(25); // set the default line width
      paintLine.setStrokeCap(Paint.Cap.ROUND); // rounded line ends
      pathMap = new HashMap<Integer, Path>();
      previousPointMap = new HashMap<Integer, Point>();
   } // end DoodleView constructor

   // Method onSizeChanged creates BitMap and Canvas after app displays
   @Override
   public void onSizeChanged(int w, int h, int oldW, int oldH)
   {
      bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
      bitmapCanvas = new Canvas(bitmap);
      bitmap.eraseColor(Color.parseColor("#80FFFFFF")); // erase the BitMap with white
   } // end method onSizeChanged

   // clear the painting
   public void recycling()
   {
       bitmap.recycle();
   }

写字板:

public void write_board () 
{
    writing_dialog = new Dialog(Apple.this, android.R.style.Theme_Translucent_NoTitleBar);
    WindowManager.LayoutParams lp = writing_dialog.getWindow().getAttributes();
    lp.dimAmount = 0.5f;
    writing_dialog.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);

    Window window = writing_dialog.getWindow();
    window.setGravity(Gravity.CENTER);

    writing_dialog.setContentView(R.layout.alert_drawing_pad);
    writing_dialog.setCancelable(true);
    writing_dialog.show();
    writing_dialog.setVolumeControlStream(AudioManager.STREAM_MUSIC);   

    doodleView = (DoodleView) writing_dialog.findViewById(R.id.doodleView);

        alert_close.setOnClickListener(new OnClickListener() 
        {
            public void onClick(View v) 
            {
                writing_dialog.dismiss();
                doodleView.recycling();
                return;
            }
        });

问题:

发现多次打开对话框后(三星Note2打开7到8次)，对话框会延迟几秒，手机无 react ，过一会再按，对话框又会出现一切正常。

此时logcat报E/OpenGLRenderer(25296): Out of memory!

它会持续一段时间而不会挂起。

然而，如果进一步按绘图板，它会出现严重的内存错误，这一次系统会挂起。

FATAL EXCEPTION: main
java.lang.OutOfMemoryError
    at android.graphics.Bitmap.nativeCreate(Native Method)
    at android.graphics.Bitmap.createBitmap(Bitmap.java:726)
    at android.graphics.Bitmap.createBitmap(Bitmap.java:703)
    at android.graphics.Bitmap.createBitmap(Bitmap.java:670)
    at com.abc.abc.DoodleView.onSizeChanged(DoodleView.java:60)
    at android.view.View.sizeChange(View.java:15326)
    at android.view.View.setFrame(View.java:15290)
    at android.view.View.layout(View.java:15201)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1076)
    at android.view.View.layout(View.java:15204)
    at android.view.ViewGroup.layout(ViewGroup.java:4793)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1076)
    at android.view.View.layout(View.java:15204)
    at android.view.ViewGroup.layout(ViewGroup.java:4793)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
    at android.view.View.layout(View.java:15204)
    at android.view.ViewGroup.layout(ViewGroup.java:4793)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1677)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1531)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1440)
    at android.view.View.layout(View.java:15204)
    at android.view.ViewGroup.layout(ViewGroup.java:4793)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
    at android.view.View.layout(View.java:15204)
    at android.view.ViewGroup.layout(ViewGroup.java:4793)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2263)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2009)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1251)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6379)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:791)
    at android.view.Choreographer.doCallbacks(Choreographer.java:591)
    at android.view.Choreographer.doFrame(Choreographer.java:561)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:777)
    at android.os.Handler.handleCallback(Handler.java:730)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:5493)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:525)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
    at dalvik.system.NativeStart.main(Native Method)

我已经研究并添加了
bitmap.recycle(); 每当用户关闭对话框时。但它仍然报同样的错误。

有没有办法在用户关闭对话框时处理位图？

谢谢!

最佳答案

您应该在关闭对话框时调用它

bitmap.recycle();
bitmap = null;

bitmap.recycle(); 释放位图中使用的 native 堆。 而设置为null是为了帮助GC快速收集你的reference。

关于Android:以编程方式释放位图内存资源，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20715442/