android - 第二次从相机捕获时无法加载图像

Question

我一直在使用 Camera Intent 捕捉图像。这是第一次它完美地工作，我能够捕获图像并在 ImageView 中显示它。但是当我第二次尝试拍摄不同的图像时，它仍然显示相同的旧图像。

这是我的 Camera Intent 和 onActivityResult() 代码

       Uri selectedImage;
        private Uri imageUri;


         private void activeTakePhoto() {

                            Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                            File photo = new File(Environment.getExternalStorageDirectory(),  "Pic.jpg");
                            intent.putExtra(MediaStore.EXTRA_OUTPUT,
                                    Uri.fromFile(photo));
                            imageUri = Uri.fromFile(photo);
                            startActivityForResult(intent,REQUEST_IMAGE_CAPTURE);
                        }


      @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            switch (requestCode) {
                case RESULT_LOAD_IMAGE:
                    if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK & null != data) {
                        selectedImage = data.getData();
                        imageView.setImageURI(selectedImage);
                    }

                    break;

                case REQUEST_IMAGE_CAPTURE:
                    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
                        try {
                            selectedImage = imageUri;
                            getContentResolver().notifyChange(selectedImage, null);
                            imageView.setImageURI(imageUri);
                        } catch (Exception e) {
                            Toast.makeText(this, "Failed to load", Toast.LENGTH_SHORT)
                                    .show();
                            Log.e("Camera", e.toString());
                        }
                        Log.e("A", "AAA");
                    }
            }
        }


   submit.setOnClickListener(new View.OnClickListener() { // back to Activity A listView
            @Override
            public void onClick(View v) {
                Intent returnIntent = new Intent();
                amount = Amount.getText().toString();
                description = Description.getText().toString();
                type = spinnerType.getSelectedItem().toString();
                returnIntent.putExtra("type", type);
                returnIntent.putExtra("description", description);
                returnIntent.putExtra("amount", amount);
                if(selectedImage!=null) {
                    returnIntent.putExtra("img_uri", selectedImage.toString());
                }
                setResult(Activity.RESULT_OK, returnIntent);
                finish();
            }
        });

Activity A

 listview.setOnItemClickListener(new AdapterView.OnItemClickListener() { // if listView is clicked
            @Override
            public void onItemClick(AdapterView<?> a, View v, int position, long id) { // if list is clicked
                mClickedPosition = position;
                Object o = listview.getItemAtPosition(position);
                ImageAndText image = (ImageAndText) o;
                String type = image.getType();
                String amount = image.getAmount();
                String description = image.getDescription();
                Uri photo = image.getImage();
                String[] type1 = type.split(":");
                String[] amount1 = amount.split(":");
                String[] description1 = description.split(":");
                Intent i = new Intent(getApplication(), AddMoreClaims.class);
                i.putExtra("type", type1[1].toString().trim());
                i.putExtra("amount", amount1[1].toString().trim());
                i.putExtra("description", description1[1].toString().trim());
                i.putExtra("photo", photo);
                startActivityForResult(i, PROJECT_REQUEST_CODE);
            }
        });

已编辑(添加时间戳)

 private void activeTakePhoto() {
        String filename = "Pic_" + System.currentTimeMillis() + ".jpg";
        Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
        File photo = new File(Environment.getExternalStorageDirectory(),  "Pic.jpg");
        intent.putExtra(MediaStore.EXTRA_OUTPUT,
                Uri.fromFile(photo,filename));
        imageUri = Uri.fromFile(photo,filename);
        startActivityForResult(intent, REQUEST_IMAGE_CAPTURE);
    }

Answer 1

如果我们看一下 ImageView 的源代码，setImageURI() 方法以 if 检查开始，类似于:

public void setImageURI(@Nullable Uri uri) {
    if (mResource != 0 ||
            (mUri != uri &&
             (uri == null || mUri == null || !uri.equals(mUri)))) {

        // Drawable resolution and update code
    }
}

正如您从 !uri.equals(mUri) 中看到的，如果 Uri 传递到方法 equals() 已经设置。您的代码每次都保存到同一个文件，因此 Uri 总是相同的。

只需在调用 imageView.setImageURI(imageUri); 之前调用 imageView.setImageURI(null);。或者，您可以每次保存到不同的文件；例如，通过向文件名添加时间戳。