我知道这个问题经常被问到，但这似乎有所不同。我尝试了 StackOverflow 的 6 种解决方案，但没有成功。我正试图Notification.BigPictureStyle在他们离开应用程序时将某人制作的绘图放入其中。
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
_thread.setRunning(true);
_thread.start();
setDrawingCacheEnabled(true);
}
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
_thread.setRunning(false);
measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
layout(0, 0, getMeasuredWidth(), getMeasuredHeight());
buildDrawingCache(false);
Bitmap currentState = Bitmap.createBitmap(getDrawingCache());
setDrawingCacheEnabled(false);
NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
Intent notificationIntent = new Intent(DrawActivity.this, DrawActivity.class);
PendingIntent contentIntent = PendingIntent.getActivity(DrawActivity.this, 0, notificationIntent, Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
Notification noti = new Notification.BigPictureStyle(
new Notification.Builder(DrawActivity.this)
.setContentTitle("Your drawing")
.setContentText("Unfold to see drawing")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher)
.setContentIntent(contentIntent))
.setSummaryText("Here you can see how you left your drawing.")
.bigPicture(currentState)
.build();
manager.notify(1023, noti);
}
}
但我总是NullPointerException在这一行得到一个：
Bitmap currentState = Bitmap.createBitmap(getDrawingCache());
此代码来自 StackOverflow，启用了所有这些缓存。有人能看出有什么问题吗？
顺便说一句，我当然使用的是 Android 4.1.1。