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Im currently using this tutorial http://www.androidhive.info/2012/02/android-gridview-layout-tutorial/ for a gridview. What I'm attempting is to manipulate it so that it returns the selected picture as an activity result to my main activity so I can set it to an imageview and then be able to use the selected image later in some other task.

The problem I'm having is getting the result back to my main activity, I'm getting Uncaught handler errors. Yes I'm a noob so by all means point out my mistakes and any explanations as to where I went wrong are always helpful in learning.

My original call for startActivityForResult

Button.OnClickListener buttonClickListener4 = new Button.OnClickListener() {
  public void onClick(View ChoosePictureButton) {
    Intent intent = new Intent(PictureActivity.this, PicPicker2.class);
    startActivityForResult(intent, 2);

      } 

    };

The activity that should return the result on clicking of the image

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.grid_layout);

    GridView gridView = (GridView) findViewById(R.id.grid_view);

    // Instance of ImageAdapter Class
    gridView.setAdapter(new ImageAdapter(this));

    /**
     * On Click event for Single Gridview Item
     * */
    gridView.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View v,
                int position, long id) {

            // Sending image id to PictureActivity
            Intent i = new Intent();
            // passing array index
            i.putExtra("id", position);
            setResult(Activity.RESULT_OK, i);
            finish();
        }
    });
}

}

Where I want my original activity to catch the result

  public void onActivityResult(int reqCode, int resultCode, Intent data) {
    super.onActivityResult(reqCode, resultCode, data);

        if (resultCode == Activity.RESULT_OK) {

             if(reqCode == 1) { for another activity result.... }           

              else if (reqCode == 2) {
                Intent i = getIntent();

                // Selected image id
                int position = i.getExtras().getInt("id");
                ImageAdapter imageAdapter = new ImageAdapter(this);
                ChosenImageView.setImageResource(imageAdapter.mThumbIds[position]);
              }
            }
        }

Yes I probably butchered it, but it should give an idea of what I'm trying. My logcat is below.

10-21 16:41:30.839: E/AndroidRuntime(4978): Uncaught handler: thread main exiting due to uncaught exception
10-21 16:41:30.869: E/AndroidRuntime(4978): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=2, result=-1, data=Intent { (has extras) }} to activity {jtek.industries.com/jtek.industries.com.PictureActivity}: java.lang.NullPointerException
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.app.ActivityThread.deliverResults(ActivityThread.java:3329)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.app.ActivityThread.handleSendResult(ActivityThread.java:3371)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.app.ActivityThread.access$2700(ActivityThread.java:119)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1893)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.os.Looper.loop(Looper.java:123)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.app.ActivityThread.main(ActivityThread.java:4363)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at java.lang.reflect.Method.invokeNative(Native Method)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at java.lang.reflect.Method.invoke(Method.java:521)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at dalvik.system.NativeStart.main(Native Method)
10-21 16:41:30.869: E/AndroidRuntime(4978): Caused by: java.lang.NullPointerException
10-21 16:41:30.869: E/AndroidRuntime(4978):     at jtek.industries.com.PictureActivity.onActivityResult(PictureActivity.java:138)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.app.Activity.dispatchActivityResult(Activity.java:3828)
10-21 16:41:30.869: E/AndroidRuntime(4978):     at android.app.ActivityThread.deliverResults(ActivityThread.java:3325)
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1 回答 1

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在你的onActivityResult()- 方法中，你有什么理由用 - 方法获得意图getIntent()？

我认为您得到的意图不包含结果数据，而是启动活动的意图（可能是null）。因此，在 , 行int position = i.getExtras().getInt("id")中，i将为 null 并抛出 NPE。

看看使用提供的 Intent 数据参数是否可以解决您的问题。

于 2012-10-22T15:24:58.730 回答