在操作安卓版本23+的文件读取时，不仅要在maniests中声明，还要在代码中动态声明：
private static final int REQUEST_EXTERNAL_STORAGE = ;
private static String[] PERMISSIONS_STORAGE = {
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE}; /**
* 8 * Checks if the app has permission to write to device storage
* 9 *
* 10 * If the app does not has permission then the user will be prompted to
* 11 * grant permissions
* 12 *
* 13 * @param activity
* 14
*/
public static void verifyStoragePermissions(Activity activity) {
// Check if we have write permission
int permission = ActivityCompat.checkSelfPermission(activity,
Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) {
// We don't have permission so prompt the user
ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,
REQUEST_EXTERNAL_STORAGE);
}
}