[英]How to fix BootReciever java.lang.NullPointerException?
我收到此错误,但不知道如何解决:
09-18 10:14:34.482: E/Trace(787): error opening trace file: No such file or directory (2)
09-18 10:14:34.542: W/ResourceType(787): No package identifier when getting value for resource number 0x00000000
09-18 10:14:34.683: E/BootReceiver(787): java.lang.NullPointerException
有人可以告诉我如何解决此错误,
BroadcastReceiver Java:
public class BootReceiver extends BroadcastReceiver {
private static final String TAG="BootReceiver";
@Override
public void onReceive(Context context,Intent intent) {
try {
DisplayMetrics metrics = new DisplayMetrics();
WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
windowManager.getDefaultDisplay().getMetrics(metrics);
int height = metrics.heightPixels;
int width = metrics.widthPixels;
Bitmap tempbitMap = BitmapFactory.decodeResource(context.getResources(), MainActivity.tophone);
WallpaperManager wallpaperManager = WallpaperManager.getInstance(context);
wallpaperManager.setWallpaperOffsetSteps(1, 1);
wallpaperManager.suggestDesiredDimensions(width, height);
try {
wallpaperManager.setBitmap(tempbitMap);
} catch (IOException e) {
e.printStackTrace();
}
} catch(Exception e){
Log.e(TAG,e.toString());
}
}
}
刚启动设备且应用程序尚未打开时,应用程序找不到MainActivity.tophone
,这意味着tophone
变量尚未初始化。 由于No package identifier
,因此触发了NullPointerException
,这意味着它无法找到具有给定名称的资源,该名称实际上为空。
解决:
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