android 之 Service(Context BindService())

Service 学习第二篇，我们使用BindService()来启动Service.

第一步，同样需要继承Service ，实现它必须的方法。并把这个Service注册到AndroidManifest.xml中，做为一种隐式意图，然后等待Activity的启动。

              这里IBinder onBind(Intent intent);会返回一个IBinder 对象。就是我们Acitvity 与Service 交互的对象。

BindService.java

package com.hkrt.action;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;

public class BindService extends Service {
	private int count;
	private boolean quit;
	private MyBinder binder = new MyBinder();

	public class MyBinder extends Binder {
		public int getCount() {
			return count;
		}
	}
	@Override
	public IBinder onBind(Intent intent) {
		System.out.println("service is Binded");
		return binder;
	}
	@Override
	public void onCreate() {
		System.out.println("Service is Create");
		super.onCreate();
		new Thread(){
			@Override
			 public void run(){
				 while(!quit){
					 try {
						Thread.sleep(1000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					count++;
				 }
			 }
		}.start();
	}

	@Override
	public boolean onUnbind(Intent intent) {
		System.out.println("Service is Unbind");
		return true;
	}
	@Override
	public void onDestroy() {
		System.out.println("Service is Destroy");
		super.onDestroy();
		this.quit=true;
	}

}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.hkrt.action"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".ServiceDemo2Activity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
		<service android:name=".BindService">
			<intent-filter >
			 <action android:name="com.hkrt.action.BIND_SERVICE"/>
			</intent-filter>
		</service>
    </application>
</manifest>

第二步：我们使用三个按钮，分别绑定Service和解除绑定，和获取Service状态。

main.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:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
    <TableLayout 
       android:orientation="vertical"
       android:layout_width="fill_parent"
       android:layout_height="fill_parent"
    >
    <TableRow >
	      <Button 
	     android:layout_width="fill_parent" 
	     android:layout_height="wrap_content" 
	     android:text="绑定Service"
	     android:id="@+id/bind"
	    />
	    <Button 
	     android:layout_width="fill_parent" 
	     android:layout_height="wrap_content" 
	     android:text="解除绑定"
	     android:id="@+id/unBind"
	    />
	    <Button 
	     android:layout_width="fill_parent" 
	     android:layout_height="wrap_content" 
	     android:text="获取Service状态"
	     android:id="@+id/serviceCount"
	    />
    </TableRow>
    </TableLayout>
  
</LinearLayout>

效果图：

第三步：关键性代码。

package com.hkrt.action;

import android.app.Activity;
import android.app.Service;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class ServiceDemo2Activity extends Activity {
	Button bind, unBind, serviceCount;
	BindService.MyBinder binder;
	private ServiceConnection conn = new ServiceConnection() {
		@Override
		public void onServiceConnected(ComponentName name, IBinder service) {
			binder = (BindService.MyBinder) service;
			System.out.println("service Connected");
		}

		@Override
		public void onServiceDisconnected(ComponentName name) {
			System.out.println("service disConnectioned");
		}

	};

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		bind = (Button) findViewById(R.id.bind);
		unBind = (Button) findViewById(R.id.unBind);
		serviceCount = (Button) findViewById(R.id.serviceCount);
		final Intent intent = new Intent();
		intent.setAction("com.hkrt.action.BIND_SERVICE");
		bind.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View v) {
				bindService(intent, conn, Service.BIND_AUTO_CREATE);
			}
		});
		unBind.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View v) {
				unbindService(conn);
			}
		});
		serviceCount.setOnClickListener(new View.OnClickListener() {
			@Override
			public void onClick(View v) {
				Toast.makeText(ServiceDemo2Activity.this,
						"service的count值为" + binder.getCount(), 1).show();
			}
		});
	}
}

第四步：Service启动流程图。

Activity 与 Service 交互的结果。

Service的生命周期