安卓：在应用程序清理内存破坏 [英] android: cleaning up memory on app destroy

问题描述

我在开发的实例一堆位图对象的应用程序（例如按键，其中有位图缓存，所以他们没有得到再次呈现，再）

I am developing an app which instantiates a bunch of bitmap objects (e.g. buttons, which have cache bitmaps, so they don't have to get rendered again and again)

现在，我意识到，当我在我的华为移动设备上重复运行，并启动应用程序，我在那里的应用程序尝试分配一些内存为位图的一个点得到一个OutOfMemoryException。
所以我想这是其闹事的位图。我知道有一个bitmap.recycle（）方法，虽然。

Now, I realised that when I run and start the app repeatedly on my huawei mobile device, I get an OutOfMemoryException at a point where the app tries to allocate some memory for the bitmaps. So I guess it's the bitmaps which make trouble. I do know that there is a bitmap.recycle() method though.

现在我的问题：什么是清理内存的最佳实践？
为什么没有像查看::的onDestroy（），它可以用于清理目的而实施了一些方法查看？

Now my question: what is best practice to clean up memory? Why isn't there some View method like View::onDestroy() which can be implemented for cleanup purpose?

编辑：例如

我的CirclyButton（扩展了Button）班总是拿缓存的位图的onDraw：

my "CirclyButton" (extends Button) class always draws a cached bitmap onDraw:

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawBitmap(this.getDefaultBitmap(), 0, 0, paint);
    }
    private Bitmap getDefaultBitmap(){
        if(mBitmapDefault == null){
            mBitmapDefault = Bitmap.createBitmap(8*radius, 8*radius, Config.ARGB_8888);
            Canvas canvas = new Canvas(mBitmapDefault);
            this.drawDefault(canvas);
            return mBitmapDefault;
        }
        return mBitmapDefault;
    }

所以我想这个分配的数据应该被回收的地方...？

So I guess this allocated data should be recycled somewhere...?

推荐答案

视图不具有的onDestroy 方法，因为意见通常不被摧毁，活动做。视图将没有任何反应其活动不只是被破坏（除非你抬高不同的布局......这是不是这样的，对吧？），如果事情发生在它的活动中，你有一个回调得到调用。

Views don't have an onDestroy method because views usually don't get destroyed, activities do. A view won't just be destroyed if nothing happens to its activity (Unless you inflate a different layout... That's not the case, right?), and if something happens to its activity, you do have a callback getting called.

如果有一个循环（）方法，请确保你怎么称呼它。并删除的所有的参考内存取物品在的onDestroy ，即：

If there is a recycle() method, make sure you call it. And remove all reference to memory taking objects in the onDestroy, i.e:

@Override
public void onDestroy() {
    object1 = null;
    object2 = null;
    //...
}

所以GC可以做自己的工作。我与的AdView的AdMob ，虽然他们也有一个摧毁方法，它并没有真正帮助了同样的问题。但我删除视图的引用解决了这一问题。

So the GC can do its job. I had the same problem with the AdView of AdMob, although they did have a destroy method it didn't really help. But deleting my references of the view fixed the problem.

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