Android的READ_EXTERNAL_STORAGE权限

你有两种解决方案。快速的方法是将targetApi降低到22（build.gradle文件）。其次是使用新的精彩的许可模式：

if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE)        != PackageManager.PERMISSION_GRANTED) {    // Should we show an explanation?    if (shouldShowRequestPermissionRationale( Manifest.permission.READ_EXTERNAL_STORAGE)) {        // Explain to the user why we need to read the contacts    }    requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);    // MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE is an    // app-defined int constant that should be quite unique    return;}