在 ACTION_GET_CONTENT 意图之后有时不会调用 OnActivityResult

Question

我正在开发一个图像编辑 Android 应用程序。在我的一项活动中，我调用了从 onCreate() 中的图库中选择图像的意图，如下所示：

Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE);

然后我收到这样的数据：

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    Crashlytics.log("onActivityResult called");
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == PICK_IMAGE && resultCode == Activity.RESULT_OK && data != null) {
        Crashlytics.log("Data received from image pick intent");
        imageUri = data.getData();
        loadImage();
    } else {
        //if we do not select a picture, go back to the dashboard
        Crashlytics.log("Data not received");
        onBackPressed();
        Log.d(TAG, "no picture selected");
    }
}

loadImage 方法：

private void loadImage() {
    try {
        photoBitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
    } catch (IOException e) {
        Crashlytics.log("IOException from getBitmap");
        Log.d(TAG, e.getMessage());
        showToastAndPressBack();
        return;
    }

    if (photoBitmap == null) {
        Crashlytics.log("photoBitmap is null in onActivityResult");
        showToastAndPressBack();
        return;
    }

    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);
    imgVWidth = size.x;
    int height = size.y;
    imgVHeight = (int) (((float) imgVWidth / photoBitmap.getWidth()) * photoBitmap.getHeight());
    photoInImgViewBitmap = Bitmap.createScaledBitmap(photoBitmap, imgVWidth, imgVHeight, true);
    imageAlreadyPicked = true;
}

现在我的问题是，有时我在 Crashlytics 中看到 NPE-s 声称当用户按下下一个按钮时 photoBitmap 为空。

@OnClick(R.id.toolbar_next)
void onToolbarNextClick() {
    float originalScale = (float) (previewImageView.getHeight()) / (float) (photoBitmap.getHeight());
    ...
}

我看到的唯一 Crashlytics 日志是用户离开的意图（我在 onPause 中放置了一个 Crashlytics 日志）。 onActivityResult 没有日志，所以我最好的猜测是 onActivityResult 没有被调用，因此我的位图没有加载，因此当用户按下下一步时它将为空。

问题：为什么有时会调用onActivityResult，有时不调用？ photoBitmap 为空还有其他可能的原因吗？

Answer 1

您必须添加以下代码才能从设备中获取图像

choosebtn.setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View v) {
         Intent i1=new Intent();
         i1.setType("image/*");
         i1.setAction(Intent.ACTION_GET_CONTENT);
         startActivityForResult(i1,1);
      }
});


@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode == 1 && resultCode == RESULT_OK && data != null && data.getData() != null)
    {
        imguri=data.getData();
        mainpreview.setImageURI(data.getData());
    } else {
        Toast.makeText(getApplicationContext(),"please choose image",Toast.LENGTH_SHORT).show();
    }
}

Answer 2

试试这个，效果很好

     Intent i = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
            startActivityForResult(i, LOAD_IMAGE_RESULTS);

  @SuppressLint("Recycle")
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

           if (requestCode == LOAD_IMAGE_RESULTS && resultCode == RESULT_OK && data != null) {
                    // Let's read picked image data - its URI
                    Uri pickedImage = data.getData();

                    // Let's read picked image path using content resolver
                    String[] filePath = {MediaStore.Images.Media.DATA};
                    @SuppressLint("Recycle") Cursor cursor = null;
                    if (pickedImage != null) {
                        cursor = getContentResolver().query(pickedImage, filePath, null, null, null);
                    }
                    if (cursor != null) {
                        cursor.moveToFirst();

                        String imagePath = cursor.getString(cursor.getColumnIndex(filePath[0]));
      }
    }
}

现在您可以将imagepath 转换为位图

Answer 3

在您的代码最后一行方法之后调用super.onActivityResult。当你调用 super 时，你已经告诉 android 你已经完成了。

我还注意到您记录了一个字符序列。不要那样做你不会用这个来解决任何问题。

 Crashlytics.log("Data not received");

您需要保存一些数据。考虑到用户取消了，因为您的代码没有捕捉到这一点。

/* 假设 log 方法有一个 int 输入 */

Crashlytics.log("Data not received");
Crashlytics.log(requestCode);
Crashlytics.log(resultCode);

Answer 4

使用它从图库中选择：

Intent i = new Intent(Intent.ACTION_PICK);
i.setType("image/*");
startActivityForResult(i, REQUEST_CODE);

现在你会在 onActivityResult 中得到一个回调：

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case REQUEST_CODE:
            if (resultCode != RESULT_CANCELED) {
//use data to get the selected image
            }
            break;
    }
}

Answer 5

要启动相机活动，请使用此代码

Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);

获取位图

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);

  if(resultCode == Activity.RESULT_OK){
    if(requestCode==CAMERA_REQUEST) {
      Bitmap photo = (Bitmap) data.getExtras().get("data"); }
    }else{
      //Camera request cancelled
  }
}