最基本的java文件格式：

package com.example.activity;

import android.os.Bundle;

import android.app.Activity;

public class MainActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

}

}

 

activity跳转：intent方法。

 

package com.example.act;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.app.Activity;

import android.content.Intent;

public class MainActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

System.out.println("onCreate");

Button button1 = (Button)findViewById(R.id.button1);

button1.setOnClickListener(new OnClickListener(){

public void onClick(View V){

Intent intent=new Intent();

intent.setClass(MainActivity.this, Two.class);

startActivity(intent);

}

});

}

@Override

protected void onStart() {

// TODO Auto-generated method stub

super.onStart();

System.out.println("onStart");

}

@Override

protected void onResume() {

// TODO Auto-generated method stub

super.onResume();

System.out.println("onResume");

}

@Override

protected void onPause() {

// TODO Auto-generated method stub

super.onPause();

System.out.println("onPause");

}

@Override

protected void onStop() {

// TODO Auto-generated method stub

super.onStop();

System.out.println("onStop");

Boolean vBoolean = isFinishing();

System.out.println(vBoolean);

}

@Override

protected void onRestart() {

// TODO Auto-generated method stub

super.onRestart();

System.out.println("onRestart");

}

@Override

protected void onDestroy() {

// TODO Auto-generated method stub

super.onDestroy();

Boolean vBoolean = isFinishing();

System.out.println(vBoolean);

System.out.println("onDestory");

}

}

 

package com.example.act;

import android.support.v7.app.ActionBarActivity;

import android.content.Intent;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class Two extends ActionBarActivity {

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.two);

System.out.println("2onCreate");

Button button2 = (Button)findViewById(R.id.button2);

button2.setOnClickListener(new OnClickListener(){

public void onClick(View V){

Intent intent=new Intent();

intent.setClass(Two.this, MainActivity.class);

startActivity(intent);

}

});

}

@Override

protected void onStart() {

// TODO Auto-generated method stub

super.onStart();

System.out.println("2onStart");

}

@Override

protected void onResume() {

// TODO Auto-generated method stub

super.onResume();

System.out.println("2onResume");

}

@Override

protected void onPause() {

// TODO Auto-generated method stub

super.onPause();

System.out.println("2onPause");

}

@Override

protected void onStop() {

// TODO Auto-generated method stub

super.onStop();

System.out.println("2onStop");

Boolean vBoolean = isFinishing();

System.out.println(vBoolean);

}

@Override

protected void onRestart() {

// TODO Auto-generated method stub

super.onRestart();

System.out.println("2onRestart");

}

@Override

protected void onDestroy() {

// TODO Auto-generated method stub

super.onDestroy();

Boolean vBoolean = isFinishing();

System.out.println(vBoolean);

System.out.println("2onDestory");

}

}

 

 还要在AndroidManifest.xml中添加

<activity

android:name=".Two"

android:label="@string/title_activity_two" >

</activity>

 

 

 

在位置：

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name=".MainActivity"

android:label="@string/app_name" >

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

<activity

android:name=".Two"

android:label="@string/title_activity_two" >

</activity>

</application>

 

 

 

两个activity直接传递消息：

intent来执行

核心代码：1

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_extra);

Button button1 = (Button)findViewById(R.id.button1);

button1.setOnClickListener(new OnClickListener() {

public void onClick(View v) {

// TODO Auto-generated method stub

Intent intent=new Intent();

intent.setClass(ExtraActivity.this, ResultActivity.class);//当前act和即将启动的act

Bundle bundle = new Bundle();

bundle.putString("data", "1"); //见和值

intent.putExtras(bundle);//传递数据

startActivityForResult(intent,0);

}

});

}

2

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_result);

final Intent intent = getIntent();

String result = intent.getStringExtra("data");//获取键为data的字典所传递的字符串型数据

Toast.makeText(ResultActivity.this, result, Toast.LENGTH_SHORT).show();//显示出来

Button button2 = (Button)findViewById(R.id.button2);

button2.setOnClickListener(new OnClickListener() {

public void onClick(View v) {

// TODO Auto-generated method stub

setResult(RESULT_OK, intent);

finish();

}

});

}