java - 如何将任何类型的文件从 Assets 文件移动/复制到 JAVA 中的范围存储 ANDROID Q？

Question

我已经成功地对图像执行了此操作，但我无法对其他类型的文件执行此操作，在我的情况下，我尝试插入一个数据库。

这是图像代码的示例:

 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q){
        try {
            try {
                pictures = assetManager.list("photos/dataset1");
            } catch (IOException e) {
                Log.e("tag", "Failed to get asset file list.", e);
            }
            if (pictures != null) {
                for (String filename : pictures) {
                    InputStream in;
                    OutputStream out;
                    InputStream inputStream = assetManager.open("photos/dataset1/"+filename);
                    Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                    saveImageToGallery(bitmap);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

下面的方法适用于图像:

public void saveImageToGallery(Bitmap bitmap) {
    OutputStream outputStream;
    Context myContext = requireContext();
    try {
        if(Build.VERSION.SDK_INT >=Build.VERSION_CODES.Q){
            ContentResolver contentResolver = requireContext().getContentResolver();
            ContentValues contentValues = new ContentValues();
            contentValues.put(MediaStore.MediaColumns.DISPLAY_NAME,"Image_"+".jpg");
            contentValues.put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_PICTURES);
            Uri imageUri = contentResolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues);
            outputStream = contentResolver.openOutputStream(Objects.requireNonNull(imageUri));
            bitmap.compress(Bitmap.CompressFormat.JPEG,100, outputStream);
            Objects.requireNonNull(outputStream);

        }
    }catch (FileNotFoundException e) {

        e.printStackTrace();
    }
}

还有我对其他类型文件的尝试:

        AssetManager assetManager = Objects.requireNonNull(requireContext()).getAssets();
    Context myContext = requireContext();
    //Essential for creating the external storage directory for the first launch
    myContext.getExternalFilesDir(null);
    File databasesFolder = new File(myContext.getExternalFilesDir(null).getParent(), "com.mydb.orca/databases");
    databasesFolder.mkdirs();

 if (files!= null) {
        for (String filename : files) {
            InputStream in;
            OutputStream out;
            try {
                in = assetManager.open("database/test/" + filename);
                File outFile = new File(databasesFolder, filename);
                out = new FileOutputStream(outFile);
                copyFile(in, out);
                in.close();
                out.flush();
                out.close();
            } catch (IOException e) {
                Log.e("tag", "Failed to copy asset file: " + filename, e);
            }
        }
    } else {
        Log.e("Error NPE", "files is null");
    }



    private void copyFile(InputStream in, OutputStream out) throws IOException {
    byte[] buffer = new byte[1024];
    int read;
    while ((read = in.read(buffer)) != -1) {
        out.write(buffer, 0, read);
    }
}

上面的这段代码不起作用，我的意思是，我没有得到任何错误或期望的结果。我想要这样的东西或类似于我的图像功能但适用于任何类型文件的功能。 当我运行我的应用程序时，我没有出现任何错误，但是什么也没有发生

Answer 1

我终于找到了解决方案，我敢肯定这不是最好的方法，但它确实有效。 我通过这种方式授予我访问所有文件的权限:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R){
  try {
        Intent intentFiles = new Intent();
        intentFiles.setAction(Settings.ACTION_MANAGE_ALL_FILES_ACCESS_PERMISSION);
        Uri uriFiles = Uri.fromParts("package", myContext.getPackageName(), null);
        intentFiles.setData(uriFiles);
        myContext.startActivity(intentFiles);
       } catch (Exception e)
       {
        Intent intentFiles = new Intent();
        intentFiles.setAction(Settings.ACTION_MANAGE_ALL_FILES_ACCESS_PERMISSION);
        myContext.startActivity(intentFiles);
       }

将此行添加到您的 list 中:

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

之后，下面的代码开始工作了:

AssetManager assetManager = Objects.requireNonNull(requireContext()).getAssets();
Context myContext = requireContext();
//Essential for creating the external storage directory for the first launch
myContext.getExternalFilesDir(null);
File databasesFolder = new File(myContext.getExternalFilesDir(null).getParent(), "com.mydb.orca/databases");
databasesFolder.mkdirs();

 if (files!= null) {
    for (String filename : files) {
        InputStream in;
        OutputStream out;
        try {
            in = assetManager.open("database/test/" + filename);
            File outFile = new File(databasesFolder, filename);
            out = new FileOutputStream(outFile);
            copyFile(in, out);
            in.close();
            out.flush();
            out.close();
        } catch (IOException e) {
            Log.e("tag", "Failed to copy asset file: " + filename, e);
        }
    }
} else {
    Log.e("Error NPE", "files is null");
}



private void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
    out.write(buffer, 0, read);
}

如果有人有最好的解决方案那应该很好

我在 android 11 上测试过，它可以工作