Android6.0以后动态增加权限

private void test() throws IOException {

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
int hasWritePermission = checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (hasWritePermission != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 101);
return;
}
}
　　　　//操作
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);

if (requestCode == 101) {

if (permissions[0].equals(Manifest.permission.WRITE_EXTERNAL_STORAGE)//
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
try {
test();
} catch (IOException e) {
e.printStackTrace();
}
} else {
Toast.makeText(this, "拒绝了权限", Toast.LENGTH_SHORT).show();
}

}
}