FileNotFoundException 打开失败：在将图像文件保存到 android 上的内部存储期间，EPERM（不允许操作）

当我尝试将图像保存到Android上的内部存储时，我遇到了这个问题。

public static String setImage(Bitmap image) {
    if (image != null) {
        FileOutputStream outputStream = null;
        File dir = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Caramel");
        dir.mkdir();
        String fileName = System.currentTimeMillis() + ".jpg";
        File file = new File(dir, fileName);
        try {
            outputStream = new FileOutputStream(file);
            image.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
            outputStream.flush();
            outputStream.close();
            return fileName;
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (outputStream != null) {
                    outputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    return null;
}

一切都很好，很顺利，我可以在调试模式下看到我的位图图像，但无论如何，我得到下一个错误：

W/System.err: java.io.FileNotFoundException: /storage/emulated/0/Caramel/1587724428205.jpg: open failed: EPERM (Operation not permitted)
    W/System.err:     at libcore.io.IoBridge.open(IoBridge.java:495)
    W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:235)
    W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:186)
    W/System.err:     at com.example.caramel.Position.setImage(Position.java:176)
    W/System.err:     at com.example.caramel.PositionActivity.onActivityResult(PositionActivity.java:129)
    W/System.err:     at android.app.Activity.dispatchActivityResult(Activity.java:8300)
    W/System.err:     at android.app.ActivityThread.deliverResults(ActivityThread.java:4905)
    W/System.err:     at android.app.ActivityThread.handleSendResult(ActivityThread.java:4953)
    W/System.err:     at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:51)
    W/System.err:     at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    W/System.err:     at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    W/System.err:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2043)
    W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:106)
    W/System.err:     at android.os.Looper.loop(Looper.java:216)
    W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7464)
    W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
    W/System.err:     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:549)
    W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:955)
    W/System.err: Caused by: android.system.ErrnoException: open failed: EPERM (Operation not permitted)
    W/System.err:     at libcore.io.Linux.open(Native Method)
    W/System.err:     at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
    W/System.err:     at libcore.io.BlockGuardOs.open(BlockGuardOs.java:254)
    W/System.err:     at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
    W/System.err:     at android.app.ActivityThread$AndroidOs.open(ActivityThread.java:7360)
    W/System.err:     at libcore.io.IoBridge.open(IoBridge.java:481)
    W/System.err:   ... 17 more

看起来，这个原因可能在我的清单.xml文件中，但我已经设置了这些权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />

谢谢你的支持，伙计们。