Question

我为我的应用程序设计了一个已经可以使用的小部件，但是现在当我单击该小部件时，遇到了以下错误。Error occurred

我的代码

@Override
    protected void onResume() {
        super.onResume();

        View v1 = getWindow().getDecorView().getRootView();
        v1.setDrawingCacheEnabled(true);
        Bitmap bitmap = Bitmap.createBitmap(v1.getDrawingCache());

        //ByteArrayOutputStream out = new ByteArrayOutputStream();
        //bitmap.compress(Bitmap.CompressFormat.PNG,90,out);

        v1.setDrawingCacheEnabled(false);

        NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
        builder.setSmallIcon(R.mipmap.ic_launcher)
                .setLargeIcon(bitmap)
                .setContentTitle("title")
                .setContentText("message:")
                .setAutoCancel(true)
                .setOngoing(false)
                .setTicker("ticker");

        NotificationManager mNotifyMgr = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        mNotifyMgr.notify(123456, builder.build());
    }

发生错误：

  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.Bitmap.getWidth()' on a null object reference
    at android.graphics.Bitmap.createBitmap(Bitmap.java:771)
    at com.blackswan.shaghayeghaccounting.transactions.TransparentQuickActionActivity.onResume(TransparentQuickActionActivity.java:113)
    at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1287)
    at android.app.Activity.performResume(Activity.java:7015)
    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:4210)
    at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:4323) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3426) 
    at android.app.ActivityThread.access$1100(ActivityThread.java:229) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1821) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:148) 
    at android.app.ActivityThread.main(ActivityThread.java:7325) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

04-04 16：10：27.445 25895-25895 / com.blackswan.shaghayeghaccounting E / Android运行时：致命异常：主要流程：com.blackswan.shaghayeghaccounting，PID：25895 java.lang.RuntimeException：无法恢复活动{com.blackswan.shaghayeghaccounting / com.blackswan.shaghayeghaccounting.transactions.TransparentQuickActionActivity}：java.lang.NullPointerException：尝试调用虚拟方法'int android.graphics.Bitmap.getWidth（） '在空对象引用上在android.app.ActivityThread.performResumeActivity（ActivityThread.java:4221）在android.app.ActivityThread.handleResumeActivity（ActivityThread.java:4323）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:3426）在android.app.ActivityThread.access $ 1100（ActivityThread.java:229）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1821）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:148）在android.app.ActivityThread.main（ActivityThread.java:7325）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1230）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1120）原因：java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法'int android.graphics.Bitmap.getWidth（）' 在android.graphics.Bitmap.createBitmap（Bitmap.java:771）

Answer 1

尝试一下：

View viewBitmap = getWindow().getDecorView().getRootView();
viewBitmap.setDrawingCacheEnabled(true);
viewBitmap.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),     
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
viewBitmap.layout(0, 0, viewBitmap .getMeasuredWidth(), viewBitmap.getMeasuredHeight()); 
viewBitmap.buildDrawingCache(true);
Bitmap b = Bitmap.createBitmap(viewBitmap .getDrawingCache());
viewBitmap.setDrawingCacheEnabled(false);

如何在Android应用中解决此错误？

1 个答案: