java Canvas尝试使用回收的位图
自从我将我的SDK/ADT升级到Android 4.4以来的最新变化，我不确定这是否与此相关，但这是自这个错误开始以来唯一的重大变化，我在我的应用程序中遇到了这个错误
日志中没有说明这在我的应用程序中发生的位置。尽管有对DrawerLayout的引用。另外，它似乎引用了支持库v4，但我使用的是v13
11-16 15:45:12.406: E/AndroidRuntime(1236): FATAL EXCEPTION: main
11-16 15:45:12.406: E/AndroidRuntime(1236): java.lang.RuntimeException: Canvas: trying to use a recycled bitmap 安卓.graphics.Bitmap@41f1e4e8
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.graphics.Canvas.throwIfRecycled(Canvas.java:1058)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.graphics.Canvas.drawBitmap(Canvas.java:1097)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.View.draw(View.java:13854)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.drawChild(ViewGroup.java:3086)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.support.v4.widget.DrawerLayout.drawChild(DrawerLayout.java:804)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.dispatchDraw(ViewGroup.java:2923)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.View.draw(View.java:13823)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.drawChild(ViewGroup.java:3086)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.dispatchDraw(ViewGroup.java:2923)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.View.draw(View.java:13823)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.drawChild(ViewGroup.java:3086)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.dispatchDraw(ViewGroup.java:2923)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.View.draw(View.java:13823)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.drawChild(ViewGroup.java:3086)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewGroup.dispatchDraw(ViewGroup.java:2923)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.View.draw(View.java:13947)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.widget.FrameLayout.draw(FrameLayout.java:467)
11-16 15:45:12.406: E/AndroidRuntime(1236): at com.安卓.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:2224)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewRootImpl.drawSoftware(ViewRootImpl.java:2482)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewRootImpl.draw(ViewRootImpl.java:2395)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewRootImpl.performDraw(ViewRootImpl.java:2239)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1872)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.Choreographer.doCallbacks(Choreographer.java:562)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.Choreographer.doFrame(Choreographer.java:532)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.os.Handler.handleCallback(Handler.java:730)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.os.Handler.dispatchMessage(Handler.java:92)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.os.Looper.loop(Looper.java:137)
11-16 15:45:12.406: E/AndroidRuntime(1236): at 安卓.app.ActivityThread.main(ActivityThread.java:5103)
11-16 15:45:12.406: E/AndroidRuntime(1236): at java.lang.reflect.Method.invokeNative(Native Method)
11-16 15:45:12.406: E/AndroidRuntime(1236): at java.lang.reflect.Method.invoke(Method.java:525)
11-16 15:45:12.406: E/AndroidRuntime(1236): at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
11-16 15:45:12.406: E/AndroidRuntime(1236): at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-16 15:45:12.406: E/AndroidRuntime(1236): at dalvik.system.NativeStart.main(Native Method)
这里是我仅有的在异步任务中使用BitMap的代码；这与我的抽屉listView标题中的图像有关：
static class GetProfileImageURL extends AsyncTask<String, String, Void> {
private Bitmap b;
private Context mContext;
public GetProfileImageURL(Context c) {
mContext = c;
}
@Override
protected Void doInBackground(String... params) {
URL url;
try {
String profImage = String.valueOf(Rateit.userId);
url = new URL(Rateit.PROFILE_PIC_URL + profImage + ".jpg");
b = BitmapFactory.decodeStream(url.openConnection()
.getInputStream());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void v) {
if (mContext != null) {
if (b != null) {
userIcon.setImageBitmap(ImageHelper.getRoundedCornerBitmap(
b, 50));
}
}
}
}
这个AsyncTask仅在创建Activity时调用
根据请求，ImageHelper类：
public class ImageHelper {
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = pixels;
final Rect topRightRect = new Rect(bitmap.getWidth()/2, 0, bitmap.getWidth(), bitmap.getHeight()/2);
final Rect bottomRect = new Rect(0, bitmap.getHeight()/2, bitmap.getWidth(), bitmap.getHeight());
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
// Fill in upper right corner
canvas.drawRect(topRightRect, paint);
// Fill in bottom corners
canvas.drawRect(bottomRect, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
# 1 楼答案
我来猜一猜
在OnCreate中，引用抽屉的布局组件时，布局管理器。充气机没有意识到任务中固有的异步延迟，因此它在不知道异步任务尚未完成的情况下继续进行
问题可能是，在onCreate（）中构建的视图需要能够在任务完成之前将某些内容组合在一起。当任务完成时，它需要更改视图资源的状态，并发出某些视图组件应该刷新的信号。例如，参考资料中的一个虚拟bmp代表圆形位图，很快就会从网络上的异步检索中出现
我不知道你为什么不在<；4.4.
我想你的问题与方向改变无关
有可能this code会进一步澄清asnyc导致的一些滞后问题。可能根本不相关