Activity声明周期1

oncreate():在Activity对象第一次创建时调用

onStart():当Activity变得可见时调用该函数

onResume():当Activity开始准备于用户交互时调用该方法（即获得焦点）

onpause():当系统即将启动另外一个Activity时调用该函数

onstop():当Activity变得不可见时调用该函数

onDestroy();当Activity被销毁之前将会调用该函数

onRestart():当一个Activity再次启动之前将会调用该函数

FirstActivity.java

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 FirstActivity extends Activity {

    private Button myButton;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        System.out.println("FirstAcvity ---> onCreate");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        myButton = (Button)findViewById(R.id.myButton);
        myButton.setText("启动第二个Activity");
        myButton.setOnClickListener(new ButtonOnClickListener());
    }
    
    
    @Override
    protected void onDestroy() {
        System.out.println("FirstAcvity --->onDestory");
        super.onDestroy();
    }
    
    
    @Override
    protected void onPause() {
        System.out.println("FirstAcvity --->onPause");
        super.onPause();
    }
    
    @Override
    protected void onRestart() {
        System.out.println("FirstAcvity --->onRestart");
        super.onRestart();
    }
    
    
    @Override
    protected void onResume() {
        System.out.println("FirstAcvity --->onResume");
        super.onResume();
    }


    @Override
    protected void onStart() {
        System.out.println("FirstAcvity --->onStart");
        super.onStart();
    }

    
    @Override
    protected void onStop() {
        System.out.println("FirstAcvity --->onStop");
        super.onStop();
    }


    class ButtonOnClickListener implements OnClickListener{
        public void onClick(View v) {
            Intent intent = new Intent();
            intent.setClass(FirstActivity.this,SecondActivity.class);
            FirstActivity.this.startActivity(intent);
        }
        
    }
}

 mian.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:id="@+id/myTextView"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    />
<Button
    android:id="@+id/myButton"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    />
</LinearLayout>

SecondActivity.java

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

public class SecondActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        System.out.println("SecondActivity--->onCreate");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second);
    }

    @Override
    protected void onDestroy() {
        System.out.println("SecondActivity--->onDestory");
        super.onDestroy();
    }

    @Override
    protected void onPause() {
        System.out.println("SecondActivity--->onPause");
        super.onPause();
    }

    @Override
    protected void onRestart() {
        System.out.println("SecondActivity--->onRestart");
        super.onRestart();
    }

    @Override
    protected void onResume() {
        System.out.println("SecondActivity--->onResume");
        super.onResume();
    }

    @Override
    protected void onStart() {
        System.out.println("SecondActivity--->onStart");
        super.onStart();
    }

    @Override
    protected void onStop() {
        System.out.println("SecondActivity--->onStop");
        super.onStop();
    }
    
    
    
}

second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
    
    <TextView
    android:id="@+id/textview"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="huangjianfeng"
    />

</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mars.activity04"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="4"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.mars.activity04.FirstActivity"
            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=".SecondActivity" android:label="@string/second"/>
    </application>

</manifest>

string.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">Activity04</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>
    <string name="second">第二个Activity</string>
</resources>

当启动应用程序时，启动了程序的第一个Activity，调用该Activity的onCreate(),onStart(),onResume()等方法

当启动应用程序的第二个Activity时,调用第一个Activity的onPause()和调用第二个Activity的onCreate(),onStart(),onResume()等方法，然后又调用第一个Activity的onStop()方法

当点击后退按钮回到第一个Activity的时候，调用第二个Activity的onPause()方法和调用第一个Activity的onRestart(),onStart(),onResume()等方法，然后调用第二个Activity的onStop()方法和onDestory()方法