Question

我目前正在使用本教程http://www.androidhive.info/2012/02/android-gridview-layout-tutorial/进行gridview。我正在尝试的是操纵它，以便它将所选图片作为活动结果返回到我的主要活动，这样我就可以将其设置为imageview，然后能够在稍后的其他任务中使用所选图像。

我遇到的问题是将结果返回到我的主要活动，我收到了未捕获的处理程序错误。是的，我是一个菜鸟，所以一定要指出我的错误和任何解释我出错的地方总是有助于学习。

我对startActivityForResult的原始调用

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

      } 

    };

单击图像时应返回结果的活动

@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();
        }
    });
}

}

我希望我的原始活动能够捕获结果

  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]);
              }
            }
        }

是的我可能已经宰了它，但它应该让我知道我在尝试什么。我的logcat在下面。

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)

Answer 1

在onActivityResult() - 方法中，您有没有理由使用getIntent()方法获取意图？

我认为你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。

查看使用提供的Intent数据参数是否解决了您的问题。

未捕获的处理程序错误从gridview返回图像作为活动结果

1 个答案: