Bitmap est toujours null

Question

J'ai une MainActivity et l'activité contient une vue. Maintenant, je veux enregistrer la vue (ou mieux dit l'image, la vue affiche) sur le stockage interne en cliquant sur le FAB. Le problème est que l'application se bloque toujours avec une exception Pointeur nul. Le bitmap ou en particulier la largeur et la hauteur de la vue semble être nul.

Mon MainActivtiy

final FractalView fw = new FractalView(this); 
    fw.invalidate(); 

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); 

    fab.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 
      Snackbar.make(view, "Hier wird im finalen Release ein Screenshot gespeichert.", Snackbar.LENGTH_LONG) 
        .setAction("Action", null).show(); 


      storeImage(getScreenViewBitmap(fw)); 
     } 
    }); 

private void storeImage(Bitmap image) { 
    File pictureFile = getOutputMediaFile(); 
    if (pictureFile == null) { 
     Log.d(TAG, 
       "Error creating media file, check storage permissions: ");// e.getMessage()); 
     return; 
    } 
    try { 
     FileOutputStream fos = new FileOutputStream(pictureFile); 
     image.compress(Bitmap.CompressFormat.PNG, 20, fos); 
     fos.close(); 
    } catch (FileNotFoundException e) { 
     Log.d(TAG, "File not found: " + e.getMessage()); 
    } catch (IOException e) { 
     Log.d(TAG, "Error accessing file: " + e.getMessage()); 
    } 
} 
private Bitmap getScreenViewBitmap(View v) { 
    v.setDrawingCacheEnabled(true); 
    v.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED), 
      View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)); 
    v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight()); 

    v.buildDrawingCache(true); 
    Bitmap b = Bitmap.createBitmap(v.getDrawingCache()); 
    return b; 
    //v.setDrawingCacheEnabled(false); // clear drawing cache 
} 

private File getOutputMediaFile(){ 
    // To be safe, you should check that the SDCard is mounted 
    // using Environment.getExternalStorageState() before doing this. 
    File mediaStorageDir = new File(Environment.getExternalStorageDirectory() 
      + "/Android/data/" 
      + getApplicationContext().getPackageName() 
      + "/Files"); 

    // This location works best if you want the created images to be shared 
    // between applications and persist after your app has been uninstalled. 

    // Create the storage directory if it does not exist 
    if (! mediaStorageDir.exists()){ 
     if (! mediaStorageDir.mkdirs()){ 
      return null; 
     } 
    } 
    // Create a media file name 

    File mediaFile; 
    String mImageName="MI_" +".jpg"; 
    mediaFile = new File(mediaStorageDir.getPath() + File.separator + mImageName); 
    return mediaFile; 
} 

L'erreur

E/AndroidRuntime: FATAL EXCEPTION: main 
                      Process: de.hsd.manguli.fractalsapp, PID: 12149 
                      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:619) 
                       at de.hsd.manguli.fractalsapp.MainActivity.getScreenViewBitmap(MainActivity.java:166) 
                       at de.hsd.manguli.fractalsapp.MainActivity.access$000(MainActivity.java:34) 
                       at de.hsd.manguli.fractalsapp.MainActivity$1.onClick(MainActivity.java:69) 
                       at android.view.View.performClick(View.java:4756) 
                       at android.view.View$PerformClick.run(View.java:19749) 
                       at android.os.Handler.handleCallback(Handler.java:739) 
                       at android.os.Handler.dispatchMessage(Handler.java:95) 
                       at android.os.Looper.loop(Looper.java:135) 
                       at android.app.ActivityThread.main(ActivityThread.java:5221) 
                       at java.lang.reflect.Method.invoke(Native Method) 
                       at java.lang.reflect.Method.invoke(Method.java:372) 
                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) 

J'espère que nous pourrons résoudre le problème. Merci beaucoup :)

Answer 1

si getDrawingCache est toujours returning null: essayez ceci:

public static Bitmap loadBitmapFromView(View v) { 
    Bitmap b = Bitmap.createBitmap(v.getLayoutParams().width, v.getLayoutParams().height, Bitmap.Config.ARGB_8888);     
    Canvas c = new Canvas(b); 
    v.layout(0, 0, v.getLayoutParams().width, v.getLayoutParams().height); 
    v.draw(c); 
    return b; 
}