自定义Application使用示例——几个Activity共同操作某个变量

MainActivity如下:

package cn.testapplication;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;/** * Demo描述: * Application的基本使用 * 1 自定义OurApplication继承自Application * 2 为AndroidManifest.xml下application结点新加个name属性 *   name的具体值即为OurApplication的路径 *    * 简单流程: * 在MainActivity中点击按钮跳转到AnotherActivity.在AnotherActivity * 中修改了OurApplication中所保存的值.然后按下Back键,回到MainActivity. * 此时监测OurApplication中所保存的值. */public class MainActivity extends Activity {    private Button mButton;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);init();}private void init(){mButton=(Button) findViewById(R.id.button);mButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View view) {                Intent intent=new Intent(MainActivity.this, AnotherActivity.class);                startActivity(intent);}});}@Overrideprotected void onRestart() {super.onRestart();OurApplication ourApplication=(OurApplication) getApplication();    System.out.println("MainActivity中得到新的Password:"+ourApplication.getPassword());}}

AnotherActivity如下:

package cn.testapplication;import android.app.Activity;import android.os.Bundle;public class AnotherActivity extends Activity{   @Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.another);init();}    private void init(){    OurApplication ourApplication=(OurApplication) getApplication();    System.out.println("AnotherActivity中得到原来的Password:"+ourApplication.getPassword());    String newPassword="9527";    ourApplication.setPassword(newPassword);    System.out.println("AnotherActivity中设置新的Password:"+newPassword);    }}

OurApplication如下:

package cn.testapplication;import android.app.Application;public class OurApplication extends Application {private String applicationPassword;@Overridepublic void onCreate() {super.onCreate();applicationPassword="007";}public void setPassword(String password){applicationPassword=password;}public String getPassword(){return applicationPassword;}}

AndroidManifest.xml如下:

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="cn.testapplication"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="8" />    <application        android:name="cn.testapplication.OurApplication"        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="cn.testapplication.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="cn.testapplication.AnotherActivity"></activity>    </application></manifest>

main.xml如下:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"     >    <Button        android:id="@+id/button"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Click Me"        android:textSize="28sp"        android:layout_centerInParent="true"    /></RelativeLayout>

another.xml如下:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"     >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Another Activity"        android:textSize="28sp"        android:layout_centerInParent="true"    /></RelativeLayout>