从图库或照片中删除图片 android 8.0

Question

我想根据其 URI 从设备中的图库或照片应用程序中删除图片。我在互联网上尝试了几种方法，但没有找到。

我调用了下面的方法

deleteMethod(getPath(selectedImageUri));

这两个方法的定义在这里。

private void deleteMethod(String file_dj_path) {
    File fdelete = new File(file_dj_path);
    if (fdelete.exists()) {
        if (fdelete.delete()) {
            System.out.println("file Deleted :" + file_dj_path);
            Toast.makeText(getApplicationContext(),
                    "file Deleted", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(getApplicationContext(),
                    "file not Deleted", Toast.LENGTH_SHORT).show();
            System.out.println("file not Deleted :" + file_dj_path);
        }
    }
}

public String getPath(Uri uri) {
    String[] projection = {MediaStore.Images.Media.DATA};
    Cursor cursor = managedQuery(uri, projection, null, null, null);
    if (cursor != null) {
        //HERE YOU WILL GET A NULLPOINTER IF CURSOR IS NULL
        //THIS CAN BE, IF YOU USED OI FILE MANAGER FOR PICKING THE MEDIA
        int column_index = cursor
                .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        return cursor.getString(column_index);
    } else return null;
}

我在清单中添加权限。喜欢，

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

我的提供商看起来像：

    <paths xmlns:android="http://schemas.android.com/apk/res/android">

    <external-path path="Android/data/com.***.calculator/"
        name="files_root" />
    <external-path path="." name="external_storage_root" />


</paths>

我得到了这样的 uri：

:/storage/emulated/0/DCIM/Camera/IMG_20180804_181447.jpg

我错过了什么吗？

---

更新：

我在运行代码之前添加了运行时权限。在我运行代码后，它总是“file not Deleted”包含 else 块。

Answer 1

您还需要检查您是否有权限，如果没有在运行时获得它。在清单文件中请求权限是不够的。您可以通过这两种方法来查看您是否有写入权限，如果没有获得权限：

protected boolean checkPermission() {
  int result1 = ContextCompat.checkSelfPermission(this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE);


   if (result1 == PackageManager.PERMISSION_GRANTED  ) {
       return true;
   } else {
       return false;
   }
}

protected void requestPermission() {
   if (ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
      Toast.makeText(this, "Write External Storage permission allows us to do store images. Please allow this permission in App Settings.", Toast.LENGTH_LONG).show();
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
          requestPermissions(new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, 100);
      }
   } else {
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
          requestPermissions(new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, 100);
      }
   }


}

Answer 2

这样改

 String path = selectedImageUri.getPath() 
 deleteMethod(path);

然后里面的deleteMethod

File file = new File(new URI(path));
if (fdelete.exists()) {
if (fdelete.delete()) {
    System.out.println("file Deleted :" + uri.getPath());
} else {
    System.out.println("file not Deleted :" + uri.getPath());
}
 }

Answer 3

好吧，既然你说你也有在运行时写的权限，也许你应该在确定文件存在之后尝试删除它之前使用setWritable()方法。

Answer 4

在 Android 6.0 之后，一些权限是在运行时授予的。您可以使用此代码。

---

另外，请检查https://developer.android.com/about/versions/marshmallow/android-6.0-changes

public  boolean hasStoragePermission() {
    if (Build.VERSION.SDK_INT >= 23) {
        if (checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
                == PackageManager.PERMISSION_GRANTED) {
            Log.v(TAG,"Permission is granted");
            return true;
        } else {

            Log.v(TAG,"Permission error");
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
            return false;
        }
    }
    else { //permission is automatically granted on sdk<23 upon installation
        Log.v(TAG,"Permission is granted");
        return true;
    }
}

以下是我目前用于以编程方式删除下载的 apk 的代码。

    final File file = new File(Environment.getExternalStorageDirectory().toString() + "/" + giftapk);
    if (file.exists()) {
        if (file.delete()) {
            System.out.println("file Deleted :" + file);
        } else {
            System.out.println("file not Deleted :" + file);
        }
    }