OnActivityResult 有时在ACTION_GET_CONTENT意图之后不调用

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，我调用了一个意图，从onCreate()中的图库中挑选图像，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步按钮时，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 日志是用户离开意图(我在onPause中放置了一个Crashlytics日志)。没有onActivityResult日志，所以我最好的猜测是没有调用onActivityResult，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：为什么有时叫onActivityResult，有时不叫？是否有其他可能的原因导致photoBitmap为空？

Answer 1

必须添加以下代码才能从设备获取图像

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，它工作得很好

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

在代码的最后一行方法之后调用super.onActivityResult。 当你打电话给超级时，你已经告诉安卓你完成了。

我还注意到您记录了一个字符序列。 不要这样做，你不会用这个解决任何问题。

Crashlytics.log("Data not received");

您需要保存一些数据。 认为用户已取消，因为您的代码未捕获此内容。

/* 假设日志方法有一个 int 输入 */

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

Answer 4

使用此选项从库中进行选择：

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，请使用以下代码

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
}
}