Android学习之Service练习

首先声明:具体思路有借鉴一些其他人的CSDN博客...

目标:了解Android Service的具体流程

实现方法:通过创建一个简单的Service例子，了解Service生命周期

所学到的知识:

1.如果Service等的AndroidManifest中声明为android:exported="false"
则该服务不能够跨进程使用。

2.Service流程为 onCreate()-onStartCommand()-onStart()-stopService()-onDestroy()
或者onCreate()-onBind()-unbindService()-onDestroy()

3.stopService(new Intent(ServiceDemo.ACTION))并不能停止服务

必须使用this.stopService(new Intent(ServiceDemo.ACTION))//可能是需要上下文的缘故

4.如果是onBind创建的Service,之后执行stopService()不会有任何反应，但是可以执行onStartCommand()和onStart(),但是之后不是通过stopService()关闭而是程序退出时自动关闭(onBind在起作用)

5.如果是onStart()创建的Service,之后可以执行onBind(),退出程序时会自动关闭(相当于是onBind()在起作用而不是onStart()在起作用),但是onStart()-onBind()后，stopService()不再起作用。

6.如何判断Service已经绑定,设置一个boolean变量,bindService是设为真，Unbind时设为假(因为退出Activity时必须判断，如果已经绑定了Service才会执行unbindService(),要不然会报错)

7.若是.xml的线性布局里面将Button放在了最上面，manifest里面必须设置android:theme="@android:style/Theme.NoTitleBar.Fullscreen"，否则会出错(估计是因为标题将button的位置给占用了,两个widget冲突所致)

8.资源文件里面的名字要使用小写,如果使用大小会报错.

具体步骤:

1.创建Android工程(不使用默认的Activity,自己手动创建)名称:Test02_Service_dlc,包名：dlc.test02.service

2.在dlc.test02.service.utils里面创建一个Attributes类(该类的作用是定义一些全局参数变量，例如屏幕的宽高)

3.在dlc.test02.service包里面创建一个SplashActivity类(该类的作用是一个Splash界面，并在里面初始化各种必须的全局数据),里面通过Handler将开启MainActivity的线程post到主消息队列中，然后再关闭SplashActivity,所以最后的结果就是主线程只有MainActivity.

4.在dlc.test02.service包里面创建一个MainActivity类(该类里面有一些跳转按钮,分别对应各种不同的Service练习,本次加了一种)

5..在dlc.test02.service包里面创建一个ServiceDemo类(该类是一个Service类，里面的重写函数Log一些消息)

6..在dlc.test02.service包里面创建一个ServiceDemoActivity类(该类是本次Service实验的主要实现界面，三个按钮，分别是绑定服务，开启服务和停止服务)

7.在AndroidManifest里面进行配置

<application        android:allowBackup="true"        android:icon="@drawable/ic_service"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity android:name=".SplashActivity"              android:theme="@android:style/Theme.NoTitleBar.Fullscreen"              android:configChanges="keyboardHidden|orientation|screenSize"            >            <intent-filter >                <action android:name="android.intent.action.MAIN"/>                <category android:name="android.intent.category.LAUNCHER"/>                <!-- 隐式调用的属性 -->                <action android:name="dlc.test02.service.start"/>                <category android:name="android.intent.category.DEFAULT"/>            </intent-filter>        </activity>        <!-- 其它Activity的注册 -->        <activity android:name=".MainActivity"              android:theme="@android:style/Theme.NoTitleBar.Fullscreen"              android:configChanges="keyboardHidden|orientation|screenSize"            ></activity>        <activity android:name=".ServiceDemoActivity"              android:theme="@android:style/Theme.NoTitleBar.Fullscreen"              android:configChanges="keyboardHidden|orientation|screenSize"            ></activity>        <!-- 服务 -->        <service android:name=".ServiceDemo"             android:exported="false">            <intent-filter >                <action android:name="dlc.test02.service.ServiceDemo"/>            </intent-filter>        </service>    </application>

8.创建对应的main.xml和splash.xml和service_demo_view.xml(各自Activity对应的View)

9.开始给各自的类里面填充相应的功能

至此，整个APP就完成了！

主要就是重写了很多函数，分别Log消息出来检测。

以下是具体代码:

Attributes.java

package dlc.test02.service.utils;public class Attributes {public static int screenWidth;public static int screenHeight;}

SplashActivity.java

package dlc.test02.service;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.os.Handler;import android.util.DisplayMetrics;import android.util.Log;import dlc.test02.service.utils.Attributes;public class SplashActivity extends Activity{private static final String TAG="SplashActivity";/**创建*/@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.splash);/**通过Handler,将一个线程放入主消息队列中*/Log.i(TAG,"将MainActivity线程推入主消息队列");Handler x=new Handler();x.postDelayed(new splashHandler(), 2000);}/**功能函数*/private void initialAttributes(){//初始化屏幕宽高DisplayMetrics dm=new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(dm);Attributes.screenWidth=dm.widthPixels;Attributes.screenHeight=dm.heightPixels;}/**内部线程类，开启主Activity*/private class splashHandler implements Runnable{@Overridepublic void run() {initialAttributes();//开启主界面,显示调用startActivity(new Intent(getApplication(),MainActivity.class));//关闭Splash界面Log.i(TAG,"关闭SplashActivity");SplashActivity.this.finish();}}}

MainActivity.java

package dlc.test02.service;import android.app.Activity;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;public class MainActivity extends Activity implements OnClickListener{    private static final String TAG="MainActivity";    private Button btn_startServiceDemo;    /**创建*/    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //设置View        setContentView(R.layout.main);        btn_startServiceDemo=(Button) findViewById(R.id.btn_startServiceDemo);        btn_startServiceDemo.setOnClickListener(this);    }    //这个方法，一定得需要类实现OnClickListener接口    @Override    public void onClick(View v) {        switch(v.getId()){        case R.id.btn_startServiceDemo:            onStartServiceDemo();            break;        default:            break;        }    }    /**功能函数*/    private void onStartServiceDemo()    {        Log.i(TAG, "点击启动ServiceDemo按钮");        //开启ServiceDemoActivity界面        startActivity(new Intent(getApplication(),ServiceDemoActivity.class));    }}

ServiceDemo.java

package dlc.test02.service;import android.app.Service;import android.content.Intent;import android.content.ServiceConnection;import android.os.IBinder;import android.util.Log;public class ServiceDemo extends Service{private static final String TAG="ServiceDemo";//Service对应的Action属性,与Manifest里面配置的一致public static final String ACTION="dlc.test02.service.ServiceDemo";@Overridepublic IBinder onBind(Intent intent) {Log.i(TAG,"ServiceDemo onBind");return null;}@Overridepublic void onCreate() {super.onCreate();Log.i(TAG,"ServiceDemo onCreate");}@Override@Deprecatedpublic void onStart(Intent intent, int startId) {super.onStart(intent, startId);Log.i(TAG,"ServiceDemo onStart");}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {Log.i(TAG,"ServiceDemo onStartCommand");return super.onStartCommand(intent, flags, startId);}@Overridepublic void unbindService(ServiceConnection conn) {super.unbindService(conn);Log.i(TAG,"ServiceDemo unbindService");}@Overridepublic void onDestroy() {super.onDestroy();Log.i(TAG,"ServiceDemo onDestroy");}}

ServiceDemoActivity.java

package dlc.test02.service;import android.app.Activity;import android.content.ComponentName;import android.content.Intent;import android.content.ServiceConnection;import android.os.Bundle;import android.os.IBinder;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class ServiceDemoActivity extends Activity implements OnClickListener{private static final String TAG="ServiceDemoActivity";//是否绑定Service的标识private boolean isBindService=false;//按钮对象private Button btn_bindService;private Button btn_startService;private Button btn_stopService;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.service_demo_view);initialButtons();registListener();}@Overrideprotected void onDestroy() {Log.v(TAG, "onDestroy unbindService");  //如果已经绑定了Service,则退出时解绑if(isBindService){unbindService(conn);  isBindService=false;}super.onDestroy();}//所有按钮监听的集合@Overridepublic void onClick(View v) {switch(v.getId()){case R.id.btn_bindService:onBindService();break;case R.id.btn_startService:onStartService();break;case R.id.btn_stopService:onStopService();break;default:break;}}/**功能函数*///初始化按钮private void initialButtons(){btn_bindService=(Button) findViewById(R.id.btn_bindService);btn_startService=(Button) findViewById(R.id.btn_startService);btn_stopService=(Button) findViewById(R.id.btn_stopService);}//设置按钮监听private void registListener(){btn_bindService.setOnClickListener(this);btn_startService.setOnClickListener(this);btn_stopService.setOnClickListener(this);}/**两种不同的启动Service的方式*/private void onBindService(){Log.i(TAG, "点击启动bindService按钮");bindService(new Intent(ServiceDemo.ACTION), conn, BIND_AUTO_CREATE);  isBindService=true;}private void onStartService(){Log.i(TAG, "点击启动startService按钮");startService(new Intent(ServiceDemo.ACTION));  }private void onStopService(){Log.i(TAG, "点击stopService按钮");//由于Android的原理是只有一个Service,所以可以这么使用,它不会创建，而是得到原来的那个Servicethis.stopService(new Intent(ServiceDemo.ACTION));}/**服务器连接*/ServiceConnection conn=new ServiceConnection(){@Overridepublic void onServiceConnected(ComponentName name, IBinder service) {Log.i(TAG, "onServiceConnected");}@Overridepublic void onServiceDisconnected(ComponentName name) {Log.i(TAG, "onServiceDisconnected");}};}

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="dlc.test02.service"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="19" />    <application        android:allowBackup="true"        android:icon="@drawable/ic_service"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity android:name=".SplashActivity"              android:theme="@android:style/Theme.NoTitleBar.Fullscreen"              android:configChanges="keyboardHidden|orientation|screenSize"            >            <intent-filter >                <action android:name="android.intent.action.MAIN"/>                <category android:name="android.intent.category.LAUNCHER"/>                <!-- 隐式调用的属性 -->                <action android:name="dlc.test02.service.start"/>                <category android:name="android.intent.category.DEFAULT"/>            </intent-filter>        </activity>        <!-- 其它Activity的注册 -->        <activity android:name=".MainActivity"              android:theme="@android:style/Theme.NoTitleBar.Fullscreen"              android:configChanges="keyboardHidden|orientation|screenSize"            ></activity>        <activity android:name=".ServiceDemoActivity"              android:theme="@android:style/Theme.NoTitleBar.Fullscreen"              android:configChanges="keyboardHidden|orientation|screenSize"            ></activity>        <!-- 服务 -->        <service android:name=".ServiceDemo"             android:exported="false">            <intent-filter >                <action android:name="dlc.test02.service.ServiceDemo"/>            </intent-filter>        </service>    </application></manifest>

main.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" >    <Button android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:text="@string/btn_startServiceDemo"    android:id="@+id/btn_startServiceDemo"    ></Button></LinearLayout>

splash.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" >    <ImageView android:layout_width="match_parent"           android:layout_height="match_parent"           android:scaleType="fitCenter"           android:src="@drawable/splash_dlc"        ></ImageView></LinearLayout>

service_demo_view.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" >    <Button android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/btn_bindservice"        android:id="@+id/btn_bindService"        ></Button> <Button android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/btn_startservice"        android:id="@+id/btn_startService"        ></Button> <Button android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/btn_stopservice"        android:id="@+id/btn_stopService"        ></Button></LinearLayout>

strings.xml

<resources>    <string name="app_name">Test02_Service_dlc</string>    <string name="btn_startServiceDemo">打开ServiceDemo</string><string name="btn_bindservice">绑定服务</string><string name="btn_startservice">启动服务</string><string name="btn_stopservice">停止服务</string></resources>

整个工程的链接:http://download.csdn.net/download/u010979495/8057335