检查android手机存储中是否存在已知的文档Uri

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

String documentUriString = "content://com.android.externalstorage.documents/document/primary:Download/example.pdf";
Uri documentUri = Uri.parse(documentUriString);

ContentResolver contentResolver = getContentResolver();
String[] projection = {MediaStore.MediaColumns.DATA};
Cursor cursor = contentResolver.query(documentUri, projection, null, null, null);

if (cursor != null && cursor.moveToFirst()) {
    String filePath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.MediaColumns.DATA));
    cursor.close();
    
    // 存在已知的文档Uri，可以进行相应操作
    // 例如，可以读取、复制、删除等
} else {
    // 不存在已知的文档Uri
}