（Android）无法保存Camera Capture，无法加载图像的位图

Question

I'm trying to write code that launches the camera app, saves the image, and then displays a bitmap of the captured image.

This is the relevant code, which was adapted from https://guides.codepath.com/android/Accessing-the-Camera-and-Stored-Media :

    public static final int PICTURE_REQUEST_CODE = 1034;
    public static final String FILE_BEGIN = "note";
    private int note_id = 4;
    public static final String FILE_END = ".jpg";
    private static final String APP_TAG = "School_App";

    private void takePicture() {
    Intent i = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    i.putExtra(MediaStore.EXTRA_OUTPUT, getPhotoFileUri(FILE_BEGIN + note_id + FILE_END));
    if (i.resolveActivity(getPackageManager()) != null){
        startActivityForResult(i, PICTURE_REQUEST_CODE);
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == PICTURE_REQUEST_CODE) {
        if (resultCode == RESULT_OK) {
            Uri takenPhotoUri = getPhotoFileUri(FILE_BEGIN + note_id + FILE_END);
            Log.d("NotesDetail", takenPhotoUri.toString());
            // by this point we have the camera photo on disk
            Bitmap takenImage = BitmapFactory.decodeFile(takenPhotoUri.getPath());
            // RESIZE BITMAP, see section below
            // Load the taken image into a preview
            ImageView ivPreview = (ImageView) findViewById(R.id.iv_notes_picture);
            ivPreview.setImageBitmap(takenImage);
        } else { // Result was a failure
            Toast.makeText(this, "Picture wasn't taken!", Toast.LENGTH_SHORT).show();
        }
    }
}

private Uri getPhotoFileUri(String fileName) {
    if(isSpaceAvailable()){
        File mediaStorageDir = new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES), APP_TAG);

        if (!mediaStorageDir.exists() && !mediaStorageDir.mkdirs()){
           Log.d(APP_TAG, "Failed to make directory");
        }

        File file = new File(mediaStorageDir.getPath() + File.separator + fileName);

        Uri uri = FileProvider.getUriForFile(NotesDetail.this, "com.kfode.schoolapp.fileprovider", file);
        Log.d("getPhotoFileUri", uri.toString());
        return uri;
    }
    return null;
}

private boolean isSpaceAvailable() {
    String state = Environment.getExternalStorageState();
    return state.equals(Environment.MEDIA_MOUNTED);
}

I also have the following permissions set:

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Within the application tag of the manifest...

    <provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="com.kfode.schoolapp.fileprovider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths"
            />
    </provider>

And within the file_paths.xml

    <paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-files-path name="images"
    path="Pictures"/>

When I run the app, I get the following log messages and exception:

D/getPhotoFileUri: content://com.kfode.schoolapp.fileprovider/images/School_App/note4.jpg
D/NotesDetail: content://com.kfode.schoolapp.fileprovider/images/School_App/note4.jpg
E/BitmapFactory: Unable to decode stream: java.io.FileNotFoundException: /images/School_App/note4.jpg: open failed: ENOENT (No such file or directory)

Not sure what is going on here. Help please?

Answer 1

Bitmap takenImage = BitmapFactory.decodeFile(takenPhotoUri.getPath());

This will not work. A Uri is not a File .

Refactor getPhotoFileUri() into two methods:

• getPhotoFile() that generates your File
• getPhotoFileUri() that obtains the FileProvider Uri for that File

Then, use an image-loading library (Glide, Picasso, etc.) to populate your ImageView from the file returned by getPhotoFile() . This not only will handle all the BitmapFactory stuff for you, but it will also do that work on a background thread, so you do not freeze your UI the way you are in your current code.