试图移动图像文件，为输出目录抛出 FileNotFoundException

Question

我正在尝试找到一种简单的方法来获取具有已知路径和文件夹的图像，并将其移动到图库中的新文件夹。调用此方法时，bucketName 是通过从 android Images MediaStore 中查询的 bucketNames 列表中选择来提供的。

我遇到的问题是 try 块永远不会执行，无论 bucketName 最终是什么，因为在尝试启动 OutputStream 时，它说找不到文件并跳转到 catch 块。但是，我正在目标位置创建一个文件，所以我不确定它为什么这么说。我一直在寻找替代解决方案，但是这里几乎所有的建议似乎都是使用这种方法，或者 TransferFrom 或 TransferTo（这也会产生同样的问题）。

编辑：我应该注意，每次打开应用程序时我都会检查 Write_External_Storage 权限。

public void moveImage(int position, String bucketname)
{
    String oldPath = imgList.get(position).getImage_path();
    String newPath = oldPath.replace(imgList.get(position).getImage_bucket(), bucketname);

    Log.i("index", oldPath);
    Log.i("index", newPath);

    InputStream inputStream = null;
    OutputStream outputStream = null;

    try
    {
        File newFile = new File(newPath);
        if (!newFile.exists())
        {
            boolean result = newFile.mkdirs();
            Log.i("index", "file didnt exist");
        }

        Log.i("index", "file exists");
        inputStream = new FileInputStream(new File(oldPath));
        outputStream = new FileOutputStream(newFile);

        byte[] buffer = new byte[1024];
        int read;
        while ((read = inputStream.read(buffer)) != -1)
        {
            outputStream.write(buffer, 0, read);
        }
        inputStream.close();
        inputStream = null;

        // write the output file (You have now copied the file)
        outputStream.flush();
        outputStream.close();
        outputStream = null;
        Log.i("index", "successful");
    }
    catch (IOException ex)
    {
        ex.printStackTrace();
        Log.i("index", "unsuccessful");
    }

    //String selection = MediaStore.Images.Media.DATA + "=?";
    //String[] selectionArgs = {String.valueOf(imgList.get(position).getImage_path())};
    //ctx.getContentResolver().delete(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection, selectionArgs);

    imgList.remove(position);

    //Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    //intent.setData(Uri.fromFile(newFile));
    //ctx.sendBroadcast(intent);
}

这是我得到的堆栈跟踪 - 据说 newFile 存在，打印文件的新旧路径

I/index: /storage/emulated/0/Download/retrowave_80_s_bg_by_rafael_de_jongh-d9wsq5j.png
I/index: /storage/emulated/0/Camera/retrowave_80_s_bg_by_rafael_de_jongh-d9wsq5j.png
I/index: file exists
W/System.err: java.io.FileNotFoundException: /storage/emulated/0/Camera/retrowave_80_s_bg_by_rafael_de_jongh-d9wsq5j.png (Is a directory)
W/System.err:     at java.io.FileOutputStream.open(Native Method)
W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:221)
W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:169)
W/System.err:     at com.example.kyler.bugout.MediaServer.moveImage(MediaServer.java:255)
W/System.err:     at com.example.kyler.bugout.MainActivity$4.onBucketClick(MainActivity.java:383)
W/System.err:     at com.example.kyler.bugout.MoveImageDialogFragment$1.onClick(MoveImageDialogFragment.java:44)
W/System.err:     at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:1119)
W/System.err:     at android.widget.AdapterView.performItemClick(AdapterView.java:310)
W/System.err:     at android.widget.AbsListView.performItemClick(AbsListView.java:1155)
W/System.err:     at android.widget.AbsListView$PerformClick.run(AbsListView.java:3126)
W/System.err:     at android.widget.AbsListView$3.run(AbsListView.java:4041)
W/System.err:     at android.os.Handler.handleCallback(Handler.java:751)
W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
W/System.err:     at android.os.Looper.loop(Looper.java:154)
W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:6077)
W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
I/index: unsuccessful

Answer 1

    if (!newFile.exists())
    {
        boolean result = newFile.mkdirs();
        Log.i("index", "file didnt exist");
    }

这将创建一个目录retrowave_80_s_bg_by_rafael_de_jongh-d9wsq5j.png（实际上在您的例外中提到了该目录）。您应该将块更改为

    if (!newFile.exists())
    {
        boolean result = newFile.getParentFile().mkdirs();
        Log.i("index", "file didnt exist");
    }