隐式Intent发送前需要先检验

1 public void click(View view) {
2         Intent intent = new Intent();
3         intent.setAction("telsd/");
4         if (intent.resolveActivity(getPackageManager()) != null) {
5             startActivity(intent);
6         } else {
7             Toast.makeText(getApplicationContext(), "没有可以调用的设备", Toast.LENGTH_SHORT).show();
8         }
9     }