Not able to get rid of NullPointerException when c

问题:

In my app, I am changing the brightness of an image within an ImageView in Activity B and I'm passing the image as well as the brightness changed to Activity A. But when recieving the result in Activity A, I get a NullPointerException.

Here is part of code in Activity A:

On a button click:

btn_Edit.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {               
            Intent editIntent = new Intent(HowItWorksActivity.this,
                    EditPhotoActivity.class);
            if (current_working_image_filename != null) {
                editIntent.putExtra("current_image_filename",
                        current_working_image_filename);
                startActivityForResult(editIntent, EDITED_PICTURE);                 

            }
                       }

In onActivityResult:

if(resultCode==RESULT_OK && requestCode == EDITED_PICTURE){
        Log.e("EDITED_PIC", "IN onactivityresult");
        imageWithBorder = data.getStringExtra("ImageWithBorder");
        metrics = getResources().getDisplayMetrics();
        postcard_image = decodeSampledBitmapFromFileString(imageWithBorder,
                metrics.widthPixels, metrics.heightPixels);
        rl.setBackgroundDrawable(drawable);
        brightness = data.getIntExtra("Image_Brightness", 0);
        Log.e("brightness level", "IN onactivityresult "+brightness);
        if(brightness!=0){
        postcard_image = EditPhotoActivity.doBrightness(postcard_image,
                    brightness);
        }           
        putGestureImageOnScreen(postcard_image);

    }

In Activity B:

In onclick of a button:

btn_filter.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
          Log.e("EditPhoto", "counter value = " + counter);
          counter++;
          sbarBrightness = (SeekBar) 
                             findViewById(R.id.seekBarForBrightness);
          if (counter % 2 == 0) {
            sbarBrightness.setVisibility(View.INVISIBLE);
          } else {
            sbarBrightness.setVisibility(View.VISIBLE);
         }

sbarBrightness.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {

    @Override
    public void onProgressChanged(SeekBar seekBar,int progress, boolean 
                            fromUser) {                             
      brightness = progress;
      putGestureImageOnScreen(doBrightness(imageBitmap, brightness));
    }
      });

     }
  });

public static Bitmap doBrightness(Bitmap src, int value) {

    int width = src.getWidth();
    int height = src.getHeight();
    Bitmap bmout = Bitmap.createBitmap(width, height, src.getConfig());
    int A, R, G, B;
    int pixel;
    for (int i = 0; i < width; ++i) {
        for (int j = 0; j < height; ++j) {
            pixel = src.getPixel(i, j);
            A = Color.alpha(pixel);
            R = Color.red(pixel);
            G = Color.green(pixel);
            B = Color.blue(pixel);
            R += value;
            if (R > 255) {
                R = 255;
            } else if (R < 0) {
                R = 0;
            }
            G += value;
            if (G > 255) {
                G = 255;
            } else if (G < 0) {
                G = 0;
            }
            B += value;
            if (B > 255) {
                B = 255;
            } else if (B < 0) {
                B = 0;
            }
            bmout.setPixel(i, j, Color.argb(A, R, G, B));
        }
    }
    return bmout;

}

Here is the logcat output:

02-26 13:57:07.442: E/SEnding brightness(12750): br = 37
02-26 13:57:07.492: E/EDITED_PIC(12750): IN onactivityresult
02-26 13:57:07.492: E/brightness level(12750): IN onactivityresult 37
02-26 13:57:07.502: E/AndroidRuntime(12750): FATAL EXCEPTION: main
02-26 13:57:07.502: E/AndroidRuntime(12750): java.lang.RuntimeException: Failure
delivering result ResultInfo{who=null, request=300, result=-1, data=Intent {  
cmp=com.sample.postcare2/.HowItWorksActivity (has extras) }} to activity
{com.sample.postcare2/com.sample.postcare2.HowItWorksActivity}: 
 java.lang.NullPointerException
02-26 13:57:07.502: E/AndroidRuntime(12750):    at  
android.app.ActivityThread.deliverResults(ActivityThread.java:3387)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at  
android.app.ActivityThread.handleSendResult(ActivityThread.java:3437)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at
android.app.ActivityThread.access$1100(ActivityThread.java:139)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1291)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at
android.os.Handler.dispatchMessage(Handler.java:99)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
android.os.Looper.loop(Looper.java:154)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
android.app.ActivityThread.main(ActivityThread.java:4944)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
java.lang.reflect.Method.invokeNative(Native Method)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at   
java.lang.reflect.Method.invoke(Method.java:511)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
dalvik.system.NativeStart.main(Native Method)
02-26 13:57:07.502: E/AndroidRuntime(12750): Caused by: java.lang.NullPointerException
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
com.sample.postcare2.EditPhotoActivity.doBrightness(EditPhotoActivity.java:393)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
com.sample.postcare2.HowItWorksActivity.onActivityResult(HowItWorksActivity.java:533)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
android.app.Activity.dispatchActivityResult(Activity.java:4740)
02-26 13:57:07.502: E/AndroidRuntime(12750):    at 
android.app.ActivityThread.deliverResults(ActivityThread.java:3383)
02-26 13:57:07.502: E/AndroidRuntime(12750):    ... 11 more

Please help me to solve the NullpointerException problem.

Thanks.