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public class View implements Drawable.Callback, KeyEvent.Callback, AccessibilityEventSource {
public void setBackgroundDrawable(Drawable background) {
.....
background.setCallback(this);
......
}
}
public abstract class Drawable {
public final void setCallback(Callback cb) {
mCallback = new WeakReference<Callback>(cb);
}
}
所以最好在 onDestroy() 中调用view.getBackground().setCallback(null);
在stackoverflow的相关问答中出现了通用的unbindDrawables方法
http://stackoverflow.com/questions/9461364/exception-in-unbinddrawables
@Override
protected void onDestroy()
{
super.onDestroy();
unbindDrawables(findViewById(R.id.top_layout));
System.gc();
Drawables(View view)
{
if (view.getBackground() != null)
{
view.getBackground().setCallback(null);
view.setBackground(null); //添加
}
if (view instanceof ViewGroup && !(view instanceof AdapterView))
{
for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++)
{
unbindDrawables(((ViewGroup) view).getChildAt(i));
}
((ViewGroup) view).removeAllViews();
}
}
BitmapFactory.Options options = new BitmapFactory.Options(); //只加载图片的部分信息，减少内存占用 options.inJustDecodeBounds = true; Bitmap tmpBitmap = BitmapFactory.decodeStream(new ByteArrayInputStream(new URL(url).openStream()), null, options); //获取图片的长宽像素 int height = options.outHeight; int width = options.outWidth;
(2) 这样就在下载网络图片之前就可以知道图片的大小了，然后根据最终需要显示的图片大小进行压缩（通常Android会在绘制的时候缩放图片）
options = new BitmapFactory.Options(); options.inSampleSize = sampleSize;//压缩比列，如果是3，就会压缩到1/3 bitmap = BitmapFactory.decodeStream(new ByteArrayInputStream(new URL(url).openStream()), null, options);
这样获取的图片内存占用会小一点。
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原文地址：http://www.cnblogs.com/dongweiq/p/4241153.html
