使用Cache Uri作为MediaStore.EXTRA_OUTPUT时,相机无法正常工作/保存

Question

我试图从拍摄照片后获得完整的图像Fragment.

如果我使用文件(Uri.fromFile(file))中的Uri,拍摄照片并点击"确定"按钮后相机将不会退出(看起来无法写入Uri或谁知道什么).

使用File String,形式'/data/data/com.package.bla/cache/img198346262jpg',它不能正常工作(文件在那里,但它是空的,因为相机没有保存任何东西).

到目前为止我尝试了什么:

• 创建文件后删除文件,如本例所示.但是,相机退出后文件不存在.
• 添加外部存储READ权限,以防万一

所以我不知道为什么图像没有被保存,并且已经花费/浪费了大量时间测试并弄清楚它为什么不起作用.

分段:

private void launchCamera() {
    Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    File outputDir = getActivity().getCacheDir();
    File file = null;
    try {
        file = File.createTempFile("img", "jpg", outputDir);
    } catch (IOException e) {
        e.printStackTrace();
    }
    if (file != null) {
        mImageUri = Uri.fromFile(file);   //using Uri is not even exiting the camera
        //mImageUri = File.toString();    //If I use String instead of an Uri, it works better (ie, can accept camera photo)
        cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, mImageUri);
        startActivityForResult(cameraIntent, RESULT_TAKE_IMAGE);
    }
}


public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == Activity.RESULT_OK) {
        Bitmap original = BitmapFactory.decodeFile(mImageUri.toString(), bounds);
    }
}

编辑的代码,mImageUri.如上所述,如果我使用Uri,我甚至无法接受相机应用程序中的照片.使用String会让我接受照片,虽然照片实际上没有保存(即文件里面有0个字节).

说明:问题与保存到缓存目录有关.也许这是一个错误,我错过了一个权限或相机应用程序只是无法保存到您的应用程序私人数据目录.添加权限FLAG_GRANT_WRITE_URI_PERMISSION没有解决它.相关文章:从相机到私人应用缓存目录中存储的图像和保存相机数据缓存通过意图启动时

更新从Android 2.2开始,getExternalCacheDir()可以使用方法代替getCacheDir()

Answer 1

从 android 26+ Uri.fromFile 将不起作用，您应该使用文件提供程序。

AndroidManifest.xml

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

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

res/xml/file_paths.xml

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path
        name="external"
        path="." />
</paths>

最后

final Intent takeVideoIntent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);

// output file
File path = new File(Environment.getExternalStorageDirectory(), "tmp.mp4");

// com.mydomain.fileprovider is authorities (manifest)
// getUri from file
Uri uri = FileProvider.getUriForFile(this, "com.mydomain.fileprovider", path);

takeVideoIntent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
startActivityForResult(takeVideoIntent, 99);

在 Android 8.0 和 5.1.1 上测试

更新：在某些设备上，内置摄像头不支持 EXTRA_OUTPUT，因此，如果您想在所有设备上工作，请构建自己的摄像头模块。

Answer 2

试试这个对我来说就像魅力一样

private String selectedImagePath = "";
    final private int PICK_IMAGE = 1;
    final private int CAPTURE_IMAGE = 2;

public Uri setImageUri() {
        // Store image in dcim
        File file = new File(Environment.getExternalStorageDirectory() + "/DCIM/", "image" + new Date().getTime() + ".png");
        Uri imgUri = Uri.fromFile(file);
        this.imgPath = file.getAbsolutePath();
        return imgUri;
    }


    public String getImagePath() {
        return imgPath;
    }

btnGallery.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setType("image/*");
                intent.setAction(Intent.ACTION_GET_CONTENT);
                startActivityForResult(Intent.createChooser(intent, ""), PICK_IMAGE);

            }
        });

        btnCapture.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                final Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, setImageUri());
                startActivityForResult(intent, CAPTURE_IMAGE);
            }
        });

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode != Activity.RESULT_CANCELED) {
            if (requestCode == PICK_IMAGE) {
                selectedImagePath = getAbsolutePath(data.getData());
                imgUser.setImageBitmap(decodeFile(selectedImagePath));
            } else if (requestCode == CAPTURE_IMAGE) {
                selectedImagePath = getImagePath();
                imgUser.setImageBitmap(decodeFile(selectedImagePath));
            } else {
                super.onActivityResult(requestCode, resultCode, data);
            }
        }

    }


public Bitmap decodeFile(String path) {
        try {
            // Decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeFile(path, o);
            // The new size we want to scale to
            final int REQUIRED_SIZE = 70;

            // Find the correct scale value. It should be the power of 2.
            int scale = 1;
            while (o.outWidth / scale / 2 >= REQUIRED_SIZE && o.outHeight / scale / 2 >= REQUIRED_SIZE)
                scale *= 2;

            // Decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            return BitmapFactory.decodeFile(path, o2);
        } catch (Throwable e) {
            e.printStackTrace();
        }
        return null;

    }

public String getAbsolutePath(Uri uri) {
        String[] projection = { MediaColumns.DATA };
        @SuppressWarnings("deprecation")
        Cursor cursor = managedQuery(uri, projection, null, null, null);
        if (cursor != null) {
            int column_index = cursor.getColumnIndexOrThrow(MediaColumns.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
        } else
            return null;
    }