Android 开发笔记___Intent的使用

 public class ActRequestActivity extends AppCompatActivity implements OnClickListener {     private EditText et_request;
     private TextView tv_request;     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_act_request);
         findViewById(R.id.btn_act_request).setOnClickListener(this);
         et_request = (EditText) findViewById(R.id.et_request);
         tv_request = (TextView) findViewById(R.id.tv_request);
     }     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.btn_act_request) {
             Intent intent = new Intent();
             intent.setClass(this, ActResponseActivity.class);
             intent.putExtra("request_time", DateUtil.getNowTime());
             intent.putExtra("request_content", et_request.getText().toString());
             startActivityForResult(intent, 0);
         }
     }     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         if (data != null) {
             String response_time = data.getStringExtra("response_time");
             String response_content = data.getStringExtra("response_content");
             String desc = String.format("收到返回消息：\n应答时间为%s\n应答内容为%s",
                     response_time, response_content);
             tv_request.setText(desc);
         }
     } }

 public class ActResponseActivity extends AppCompatActivity implements OnClickListener {     private EditText et_response;
     private TextView tv_response;     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_act_response);
         findViewById(R.id.btn_act_response).setOnClickListener(this);
         et_response = (EditText) findViewById(R.id.et_response);
         tv_response = (TextView) findViewById(R.id.tv_response);         Bundle bundle = getIntent().getExtras();
         String request_time = bundle.getString("request_time");
         String request_content = bundle.getString("request_content");
         String desc = String.format("收到请求消息：\n请求时间为%s\n请求内容为%s",
                 request_time, request_content);
         tv_response.setText(desc);
     }     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.btn_act_response) {
             Intent intent = new Intent();
             Bundle bundle = new Bundle();
             bundle.putString("response_time", DateUtil.getNowTime());
             bundle.putString("response_content", et_response.getText().toString());
             intent.putExtras(bundle);
             setResult(Activity.RESULT_OK, intent);
             finish();
         }
     } }