Android Activity Intent

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

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class LifeCycleActivity extends Activity{
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.e(this.getClass().getName(), "onCreate");
    }
    
    @Override
    protected void onStart() {
        super.onStart();
        Log.e(this.getClass().getName(), "onStart");
    }
    
    @Override
    protected void onResume() {
        super.onResume();
        Log.e(this.getClass().getName(), "onResume");
    }
    
    @Override
    protected void onPause() {
        super.onPause();
        Log.e(this.getClass().getName(), "onPause");
    }
    
    @Override
    protected void onStop() {
        super.onStop();
        Log.e(this.getClass().getName(), "onStop");
    }
    
    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.e(this.getClass().getName(), "onDestroy");
    }
}

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

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends LifeCycleActivity {

    public static final String TAG = "MainActivity";
    Button button,buttonNext,buttonMsg,buttonSex,buttonHeight,buttonBack;
    
    public static final int SEX_SELECT = 1;
    public static final int HEIGHT_SELECT = 2;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //自己点击自己
        button = (Button) findViewById(R.id.main_btn);
        button.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                //定义一个意图,启动FirstActivity
                Intent intent = new Intent(MainActivity.this, MainActivity.class);
                Toast.makeText(MainActivity.this, "你点击了自己", Toast.LENGTH_SHORT).show();
                startActivity(intent);
            }
        });
        
        //启动下一个界面，不带参数
        buttonNext = (Button) findViewById(R.id.main_btn_next);
        buttonNext.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                //定义一个意图,启动FirstActivity
                Intent intent = new Intent(MainActivity.this, FirstActivity.class);
                startActivity(intent);
            }
        });
        
        //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
        buttonMsg = (Button)findViewById(R.id.main_btn_msg);
        buttonMsg.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                intent.putExtra("msg", "我要送你一句话");
                startActivity(intent);
                
            }
        });
        
        
        //启动下一个界面，选择性别，并将选择结果返回显示在MainActivity中
        buttonSex = (Button)findViewById(R.id.main_sex);
        buttonSex.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, ThirdActivity.class);
                
                startActivityForResult(intent, SEX_SELECT);
            }
        });
        
        //启动下一个界面，输入身高，并将结果返回显示在MainActivity中
        buttonHeight = (Button) findViewById(R.id.main_height);
        buttonHeight.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, FourActivity.class);
                startActivityForResult(intent, HEIGHT_SELECT);
            }
        });
        
        //退出App
        buttonBack = (Button) findViewById(R.id.main_btn_back);
        buttonBack.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                //主活动点击返回直接退出程序
                finish();
            }
        });
    }
    
    
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        
        switch (requestCode) {
        case SEX_SELECT:
            String sex;
            if(resultCode == ThirdActivity.MAN_CODE){
                sex = data.getStringExtra("sex_result");
                Log.e(TAG, "sex = "+sex);//null
                buttonSex.setText("选择了"+sex);
            }else {
                sex = data.getStringExtra("sex_result");
                buttonSex.setText("选择了"+sex);
            }
            break;
        case HEIGHT_SELECT:
            int height;
            if(resultCode == FourActivity.SUBMIT){
                //必须给默认值
                height = data.getIntExtra("height", -1);
                buttonHeight.setText(height+"cm");
            }
            break;
        default:
        }
    }
    
}

启动下一个界面，无数据传递，无返回数据，

import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class FirstActivity extends LifeCycleActivity{

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_first);
            
            //关闭这个界面，会回到上一个界面
            Button buttonBack = (Button)findViewById(R.id.first_btn_back);
            buttonBack.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    //返回到上一个界面
                    finish();
                }
            });
            
        }               
}

 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

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class SecondActivity extends LifeCycleActivity {

    TextView tv;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        tv = (TextView) findViewById(R.id.text);
        
        //获取意图
        Intent intent = getIntent();
        //通过键key获取数据值
        String data = intent.getStringExtra("msg");
        
        //显示接收到的数据
        tv.setText("收到:"+data);
        
        Button buttonBack = (Button)findViewById(R.id.second_btn_back);
        buttonBack.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });
    }
    
    
}

启动下一个界面，选择性别，并将选择结果返回显示在MainActivity中

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class ThirdActivity extends LifeCycleActivity implements OnClickListener{
    public static final int MAN_CODE = 1;
    public static final int WOMAN_CODE = 2;
    
    Button man,woman;
    Intent intent;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_third);
        
        
        man = (Button) findViewById(R.id.man);
        man.setOnClickListener(this);
        
        woman = (Button) findViewById(R.id.woman);
        woman.setOnClickListener(this);
        
    }
    
    @Override
    public void onClick(View v) {
        intent = new Intent();
        switch (v.getId()) {
        case R.id.man:
            intent.putExtra("sex_result", "男");
            
            setResult(MAN_CODE, intent);
            finish();
            break;
        case R.id.woman:
            intent.putExtra("sex_result", "女");
            setResult(WOMAN_CODE, intent);
            finish();
            break;
        default:
        }
    }
}

//启动下一个界面，输入身高，并将结果返回显示在MainActivity中

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class FourActivity extends LifeCycleActivity implements OnClickListener{
    Button submit,cancel;
    EditText et;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_four);
        
        submit = (Button) findViewById(R.id.four_submit);
        cancel = (Button) findViewById(R.id.four_cancel);
        et = (EditText) findViewById(R.id.four_edit);
        
        submit.setOnClickListener(this);
        cancel.setOnClickListener(this);
    }
    
    public static final int SUBMIT = 1;
    public static final int CANCEL = 2;
    @Override
    public void onClick(View v) {
        Intent intent = new Intent();
        switch (v.getId()) {
        case R.id.four_submit:
            int height = Integer.parseInt(et.getText().toString());
            intent.putExtra("height", height);
            setResult(SUBMIT, intent);
            finish();
            break;
        case R.id.four_cancel:
            setResult(CANCEL);
            finish();
            break;
        default:
            break;
        }
        
    }
}