java - 是什么导致了这段Java代码中的内存泄漏

Question

我编写了一个方法来调整可绘制对象的大小，但我发现它泄漏了。它是在我的游戏的 SinglePlayer Activity 中实现的，因此当我重新启动该 Activity (“再次播放”按钮)时，可用堆大小会减少，直到最终崩溃。我想关闭一项 Activity 并且不留下任何痕迹。我确信 ResizeDrawable 方法是唯一导致崩溃的方法，因为当我删除它时，问题就解决了。这是代码:

 //They don't have to be global, I guess it makes no difference
Bitmap temp;
Bitmap resbit;
Drawable resized;

Drawable ResizeDrawable(Drawable image,int width,int height) 
{
    temp = ((BitmapDrawable)image).getBitmap();
    resbit = Bitmap.createScaledBitmap(temp, width, height, true);
    resized = new BitmapDrawable(getResources(), resbit ); 
    return resized;
}

那么为什么这会填满内存？如何修改此方法或整个 Activity ，以便在 Activity 关闭后释放所有内存？

更新:

我尝试使用recycle()方法。据我了解，回收会释放位图的内存，因此可以再次使用而不会泄漏。我添加了这些行:

            if (temp != null) 
        {
            temp.recycle();
            temp = null;
        }
        if (resbit != null) 
        {
            resbit .recycle();
            resbit  = null;
        }

1) 在 ResizeDrawable 方法的开始处2)返回语句之前

这两项编辑都导致了“尝试使用回收的位图”崩溃。我哪里出错了？

更新:

我尝试删除“resbit recycle”部分。现在我能够重新启动我的 Activity 两次，然后它因同样的异常而崩溃。这怎么可能？

更新:

我尝试用以下方法重写 OnDestroy():

Runtime.getRuntime().gc(); 

和:

finish();

什么都没有改变。还尝试使用回收覆盖 OnDestroy() 。同样的“恰好两次”崩溃。

日志:

因此，原始代码在 SinglePlayer Activity 恰好重新启动 16 次后崩溃。日志:

11-16 03:46:31.115: E/AndroidRuntime(9649): FATAL EXCEPTION: main
11-16 03:46:31.115: E/AndroidRuntime(9649): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.starena/com.example.starena.SinglePlayer}: android.view.InflateException: Binary XML file line #40: Error inflating class <unknown>
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1659)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1675)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.ActivityThread.access$1500(ActivityThread.java:121)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:943)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.os.Looper.loop(Looper.java:130)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.ActivityThread.main(ActivityThread.java:3701)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at java.lang.reflect.Method.invokeNative(Native Method)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at java.lang.reflect.Method.invoke(Method.java:507)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:624)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at dalvik.system.NativeStart.main(Native Method)
11-16 03:46:31.115: E/AndroidRuntime(9649): Caused by: android.view.InflateException: Binary XML file line #40: Error inflating class <unknown>
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.view.LayoutInflater.createView(LayoutInflater.java:518)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:568)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:623)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.view.LayoutInflater.inflate(LayoutInflater.java:408)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:227)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.Activity.setContentView(Activity.java:1657)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at com.example.starena.SinglePlayer.onCreate(SinglePlayer.java:177)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
11-16 03:46:31.115: E/AndroidRuntime(9649):     ... 11 more
11-16 03:46:31.115: E/AndroidRuntime(9649): Caused by: java.lang.reflect.InvocationTargetException
11-16 03:46:31.115: E/AndroidRuntime(9649):     at java.lang.reflect.Constructor.constructNative(Native Method)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at java.lang.reflect.Constructor.newInstance(Constructor.java:415)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.view.LayoutInflater.createView(LayoutInflater.java:505)
11-16 03:46:31.115: E/AndroidRuntime(9649):     ... 22 more
11-16 03:46:31.115: E/AndroidRuntime(9649): Caused by: java.lang.OutOfMemoryError: bitmap size exceeds VM budget
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:494)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:370)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:715)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.content.res.Resources.loadDrawable(Resources.java:1720)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.content.res.TypedArray.getDrawable(TypedArray.java:601)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.widget.ImageView.<init>(ImageView.java:122)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.widget.ImageButton.<init>(ImageButton.java:85)
11-16 03:46:31.115: E/AndroidRuntime(9649):     at android.widget.ImageButton.<init>(ImageButton.java:81)
11-16 03:46:31.115: E/AndroidRuntime(9649):     ... 25 more

我如何使用它:

因此，在我的 OnCreate() 方法中，我初始化了几个 ImageButtons 和它们将使用的几个 Drawables。它看起来像这样:

Drawable1 = context.getResources().getDrawable(R.drawable.drawable1);   
Drawable1 = ResizeDrawable(Drawable1,ButtonWidth,ButtonHeight);
ImgButton1 = (ImageButton) findViewById(R.id.ImageButton02);
ImgButton1.setOnClickListener(this);
ImgButton1.setImageDrawable(Drawable1);

此外，每个图像按钮都有两个可绘制对象，我通过 OnClick() 方法在它们之间交替(我只是 setImageDrawable() 之一或另一个)。

我希望这会有所帮助。

已解决:我必须用以下方法覆盖 OnDestroy:

Drawable1 = null;
ImgButton1.setImageDrawable(null);

当然，我对每个 (ImgButton,Drawable) 对都执行了此操作，并且它停止消耗内存。我没有回收位图。

Answer 1

尝试对未使用的 Bitmap 实例调用 Bitmap.recycle()。

Bitmap.recycle()
http://developer.android.com/reference/android/graphics/Bitmap.html#recycle()