需要检查系统权限。在Android Lollipop或更低版本中，您可以使用以下代码检查和请求系统权限：

1. 检查权限是否已授予

if (ContextCompat.checkSelfPermission(context, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) { // Permission is not granted }

2. 请求权限

ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.READ_PHONE_STATE}, MY_PERMISSIONS_REQUEST_READ_PHONE_STATE);

3. 处理权限请求结果

@Override public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) { switch (requestCode) { case MY_PERMISSIONS_REQUEST_READ_PHONE_STATE: { // If request is cancelled, the result arrays are empty. if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { // Permission is granted } else { // Permission is denied } return; } } }