Android Activity Intent

Posted 2020-08-11

首先定义一个LifeCycleActivity的类，继承Activity，重写onCreat() onStart()  onResume()  onPause()  onStop()  onDestroy()

 1 import android.app.Activity;
 2 import android.os.Bundle;
 3 import android.util.Log;
 4 
 5 public class LifeCycleActivity extends Activity{
 6     
 7     @Override
 8     protected void onCreate(Bundle savedInstanceState) {
 9         super.onCreate(savedInstanceState);
10         Log.e(this.getClass().getName(), "onCreate");
11     }
12     
13     @Override
14     protected void onStart() {
15         super.onStart();
16         Log.e(this.getClass().getName(), "onStart");
17     }
18     
19     @Override
20     protected void onResume() {
21         super.onResume();
22         Log.e(this.getClass().getName(), "onResume");
23     }
24     
25     @Override
26     protected void onPause() {
27         super.onPause();
28         Log.e(this.getClass().getName(), "onPause");
29     }
30     
31     @Override
32     protected void onStop() {
33         super.onStop();
34         Log.e(this.getClass().getName(), "onStop");
35     }
36     
37     @Override
38     protected void onDestroy() {
39         super.onDestroy();
40         Log.e(this.getClass().getName(), "onDestroy");
41     }
42 }

打开APP,并启动下一个界面，然后返回主界面

点击事件监听

 

一、自己点击自己

 

  1 import android.content.Intent;
  2 import android.os.Bundle;
  3 import android.util.Log;
  4 import android.view.View;
  5 import android.view.View.OnClickListener;
  6 import android.widget.Button;
  7 import android.widget.Toast;
  8 
  9 public class MainActivity extends LifeCycleActivity {
 10 
 11     public static final String TAG = "MainActivity";
 12     Button button,buttonNext,buttonMsg,buttonSex,buttonHeight,buttonBack;
 13     
 14     public static final int SEX_SELECT = 1;
 15     public static final int HEIGHT_SELECT = 2;
 16     
 17     @Override
 18     protected void onCreate(Bundle savedInstanceState) {
 19         super.onCreate(savedInstanceState);
 20         setContentView(R.layout.activity_main);
 21         
 22         //自己点击自己
 23         button = (Button) findViewById(R.id.main_btn);
 24         button.setOnClickListener(new OnClickListener() {
 25             @Override
 26             public void onClick(View v) {
 27                 //定义一个意图,启动FirstActivity
 28                 Intent intent = new Intent(MainActivity.this, MainActivity.class);
 29                 Toast.makeText(MainActivity.this, "你点击了自己", Toast.LENGTH_SHORT).show();
 30                 startActivity(intent);
 31             }
 32         });
 33         
 34         //启动下一个界面，不带参数
 35         buttonNext = (Button) findViewById(R.id.main_btn_next);
 36         buttonNext.setOnClickListener(new OnClickListener() {
 37             @Override
 38             public void onClick(View v) {
 39                 //定义一个意图,启动FirstActivity
 40                 Intent intent = new Intent(MainActivity.this, FirstActivity.class);
 41                 startActivity(intent);
 42             }
 43         });
 44         
 45         //启动下一个界面，并传递参数给下一个界面，比如发送一个句话
 46         buttonMsg = (Button)findViewById(R.id.main_btn_msg);
 47         buttonMsg.setOnClickListener(new OnClickListener() {
 48             @Override
 49             public void onClick(View v) {
 50                 Intent intent = new Intent(MainActivity.this, SecondActivity.class);
 51                 intent.putExtra("msg", "我要送你一句话");
 52                 startActivity(intent);
 53                 
 54             }
 55         });
 56         
 57         
 58         //启动下一个界面，选择性别，并将选择结果返回显示在MainActivity中
 59         buttonSex = (Button)findViewById(R.id.main_sex);
 60         buttonSex.setOnClickListener(new OnClickListener() {
 61             @Override
 62             public void onClick(View v) {
 63                 Intent intent = new Intent(MainActivity.this, ThirdActivity.class);
 64                 
 65                 startActivityForResult(intent, SEX_SELECT);
 66             }
 67         });
 68         
 69         //启动下一个界面，输入身高，并将结果返回显示在MainActivity中
 70         buttonHeight = (Button) findViewById(R.id.main_height);
 71         buttonHeight.setOnClickListener(new OnClickListener() {
 72             @Override
 73             public void onClick(View v) {
 74                 Intent intent = new Intent(MainActivity.this, FourActivity.class);
 75                 startActivityForResult(intent, HEIGHT_SELECT);
 76             }
 77         });
 78         
 79         //退出App
 80         buttonBack = (Button) findViewById(R.id.main_btn_back);
 81         buttonBack.setOnClickListener(new OnClickListener() {
 82             @Override
 83             public void onClick(View v) {
 84                 //主活动点击返回直接退出程序
 85                 finish();
 86             }
 87         });
 88     }
 89     
 90     
 91     @Override
 92     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 93         
 94         switch (requestCode) {
 95         case SEX_SELECT:
 96             String sex;
 97             if(resultCode == ThirdActivity.MAN_CODE){
 98                 sex = data.getStringExtra("sex_result");
 99                 Log.e(TAG, "sex = "+sex);//null
100                 buttonSex.setText("选择了"+sex);
101             }else {
102                 sex = data.getStringExtra("sex_result");
103                 buttonSex.setText("选择了"+sex);
104             }
105             break;
106         case HEIGHT_SELECT:
107             int height;
108             if(resultCode == FourActivity.SUBMIT){
109                 //必须给默认值
110                 height = data.getIntExtra("height", -1);
111                 buttonHeight.setText(height+"cm");
112             }
113             break;
114         default:
115         }
116     }
117     
118 }

 

启动下一个界面，无数据传递，无返回数据，

 1 import android.os.Bundle;
 2 import android.view.View;
 3 import android.view.View.OnClickListener;
 4 import android.widget.Button;
 5 
 6 public class FirstActivity extends LifeCycleActivity{
 7 
 8         @Override
 9         protected void onCreate(Bundle savedInstanceState) {
10             super.onCreate(savedInstanceState);
11             setContentView(R.layout.activity_first);
12             
13             //关闭这个界面，会回到上一个界面
14             Button buttonBack = (Button)findViewById(R.id.first_btn_back);
15             buttonBack.setOnClickListener(new OnClickListener() {
16                 @Override
17                 public void onClick(View v) {
18                     //返回到上一个界面
19                     finish();
20                 }
21             });
22             
23         }               
26 }

 

 启动下一个界面，并传递参数给下一个界面，比如发送一个句话

 1 import android.content.Intent;
 2 import android.os.Bundle;
 3 import android.view.View;
 4 import android.view.View.OnClickListener;
 5 import android.widget.Button;
 6 import android.widget.TextView;
 7 
 8 public class SecondActivity extends LifeCycleActivity {
 9 
10     TextView tv;
11     
12     @Override
13     protected void onCreate(Bundle savedInstanceState) {
14         super.onCreate(savedInstanceState);
15         setContentView(R.layout.activity_second);
16         tv = (TextView) findViewById(R.id.text);
17         
18         //获取意图
19         Intent intent = getIntent();
20         //通过键key获取数据值
21         String data = intent.getStringExtra("msg");
22         
23         //显示接收到的数据
24         tv.setText("收到:"+data);
25         
26         Button buttonBack = (Button)findViewById(R.id.second_btn_back);
27         buttonBack.setOnClickListener(new OnClickListener() {
28             @Override
29             public void onClick(View v) {
30                 finish();
31             }
32         });
33     }
34     
35     
36 }

 

 

启动下一个界面，选择性别，并将选择结果返回显示在MainActivity中

 1 import android.content.Intent;
 2 import android.os.Bundle;
 3 import android.view.View;
 4 import android.view.View.OnClickListener;
 5 import android.widget.Button;
 6 
 7 public class ThirdActivity extends LifeCycleActivity implements OnClickListener{
 8     public static final int MAN_CODE = 1;
 9     public static final int WOMAN_CODE = 2;
10     
11     Button man,woman;
12     Intent intent;
13     @Override
14     protected void onCreate(Bundle savedInstanceState) {
15         super.onCreate(savedInstanceState);
16         setContentView(R.layout.activity_third);
17         
18         
19         man = (Button) findViewById(R.id.man);
20         man.setOnClickListener(this);
21         
22         woman = (Button) findViewById(R.id.woman);
23         woman.setOnClickListener(this);
24         
25     }
26     
27     @Override
28     public void onClick(View v) {
29         intent = new Intent();
30         switch (v.getId()) {
31         case R.id.man:
32             intent.putExtra("sex_result", "男");
33             
34             setResult(MAN_CODE, intent);
35             finish();
36             break;
37         case R.id.woman:
38             intent.putExtra("sex_result", "女");
39             setResult(WOMAN_CODE, intent);
40             finish();
41             break;
42         default:
43         }
44     }
45 }

 

//启动下一个界面，输入身高，并将结果返回显示在MainActivity中

 1 import android.content.Intent;
 2 import android.os.Bundle;
 3 import android.view.View;
 4 import android.view.View.OnClickListener;
 5 import android.widget.Button;
 6 import android.widget.EditText;
 7 
 8 public class FourActivity extends LifeCycleActivity implements OnClickListener{
 9     Button submit,cancel;
10     EditText et;
11     @Override
12     protected void onCreate(Bundle savedInstanceState) {
13         super.onCreate(savedInstanceState);
14         setContentView(R.layout.activity_four);
15         
16         submit = (Button) findViewById(R.id.four_submit);
17         cancel = (Button) findViewById(R.id.four_cancel);
18         et = (EditText) findViewById(R.id.four_edit);
19         
20         submit.setOnClickListener(this);
21         cancel.setOnClickListener(this);
22     }
23     
24     public static final int SUBMIT = 1;
25     public static final int CANCEL = 2;
26     @Override
27     public void onClick(View v) {
28         Intent intent = new Intent();
29         switch (v.getId()) {
30         case R.id.four_submit:
31             int height = Integer.parseInt(et.getText().toString());
32             intent.putExtra("height", height);
33             setResult(SUBMIT, intent);
34             finish();
35             break;
36         case R.id.four_cancel:
37             setResult(CANCEL);
38             finish();
39             break;
40         default:
41             break;
42         }
43         
44     }
45 }