java - 无法在 android 外部文件目录中创建临时文件

Question

我正在关注 Google's Taking Photos Simply教程，但它在创建临时文件时失败，出现 java.io.IOException: open failed: EACCES (Permission denied)。

这是我的AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"  package="pricez.fastshop_android" >
    <uses-permission android:name="android.permission.RECORD_AUDIO"/>
    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18"/>
    <uses-feature android:required="true" android:name="android.hardware.camera"/>
    <!-- Rest of file... -->
</manifest>

所以，我想至少这是正确的。

这是我 Activity 的相关代码:

private String mCurrentPhotoPath;
private static final int REQUEST_TAKE_PHOTO = 1;

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "/JPEG_" + timeStamp + "_"; // I forgot from where I got this, but it was from some SO question that tried to deal with a similar problem
    File absoluteFileDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES).getAbsoluteFile(); // Same as above
    Log.i("createImageFile", "absoluteFileDir.getAbsolutePath(): " + absoluteFileDir.getAbsolutePath()); // I/createImageFile﹕ absoluteFileDir.getAbsolutePath(): /storage/sdcard/Android/data/-redacted-/files/Pictures
    File image = File.createTempFile(imageFileName, ".jpg", absoluteFileDir);
    mCurrentPhotoPath = image.getAbsolutePath();
    return image;
}

public void takePhoto(View view) {
    if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
        Toast.makeText(this, "External SD card not mounted", Toast.LENGTH_LONG).show();
        return;
    }
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        File photoFile;
        try {
            photoFile = createImageFile();
        } catch (IOException e) {
            Log.e("takePhoto", "IOException", e);
            return;
        }
        takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
        startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_TAKE_PHOTO && resultCode == RESULT_OK) {
        // Get the dimensions of the View
        ImageView imgv = (ImageView)findViewById(R.id.imgPreview);
        int targetW = imgv.getWidth();
        int targetH = imgv.getHeight();
        // Get the dimensions of the bitmap
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        bmOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
        int photoW = bmOptions.outWidth;
        int photoH = bmOptions.outHeight;
        // Determine how much to scale down the image
        int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
        // Decode the image file into a Bitmap sized to fill the View
        bmOptions.inJustDecodeBounds = false;
        bmOptions.inSampleSize = scaleFactor;
        bmOptions.inPurgeable = true;
        //
        Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
        imgv.setImageBitmap(bitmap);
    }
}

编辑 1:我在 SDK 级别 19 的模拟器上运行它。

编辑 2:

如果我手动删除文件夹，getExternalStorageDirectory 开始正常工作。我让这个问题悬而未决，因为它不是真正的解决方法。如果我的代码中一切正常，我将在几天后关闭。

Answer 1

我不知道为什么(我的猜测是文件锁中的某些东西悄悄地出了可怕的错误)，但是当我删除并重新创建文件夹时它开始工作(感谢@greenapps，会如果可以的话，请投票)。此时我能做的就是思考如何以某种方式恢复。

我认为删除文件夹不是真正的解决方案，但此时我必须继续。

此外，这种情况可能不会出现在实际设备中。