Android Service与Activity之间通信的几种方式
转载请注明地址http://blog.csdn.net/xiaanming/article/details/9750689
在Android中,Activity主要负责前台页面的展示,Service主要负责需要长期运行的任务,所以在我们实际开发中,就会常常遇到Activity与Service之间的通信,我们一般在Activity中启动后台Service,通过Intent来启动,Intent中我们可以传递数据给Service,而当我们Service执行某些操作之后想要更新UI线程,我们应该怎么做呢?接下来我就介绍两种方式来实现Service与Activity之间的通信问题
- 通过Binder对象
当Activity通过调用bindService(Intent service, ServiceConnection conn,int flags),我们可以得到一个Service的一个对象实例,然后我们就可以访问Service中的方法,我们还是通过一个例子来理解一下吧,一个模拟下载的小例子,带大家理解一下通过Binder通信的方式
首先我们新建一个工程Communication,然后新建一个Service类
- <span style="font-family:System;">package com.example.communication;
- import android.app.Service;
- import android.content.Intent;
- import android.os.Binder;
- import android.os.IBinder;
- public class MsgService extends Service {
- /**
- * 进度条的最大值
- */
- public static final int MAX_PROGRESS = 100;
- /**
- * 进度条的进度值
- */
- private int progress = 0;
- /**
- * 增加get()方法,供Activity调用
- * @return 下载进度
- */
- public int getProgress() {
- return progress;
- }
- /**
- * 模拟下载任务,每秒钟更新一次
- */
- public void startDownLoad(){
- new Thread(new Runnable() {
- @Override
- public void run() {
- while(progress < MAX_PROGRESS){
- progress += 5;
- try {
- Thread.sleep(1000);
- } catch (InterruptedException e) {
- e.printStackTrace();
- }
- }
- }
- }).start();
- }
- /**
- * 返回一个Binder对象
- */
- @Override
- public IBinder onBind(Intent intent) {
- return new MsgBinder();
- }
- public class MsgBinder extends Binder{
- /**
- * 获取当前Service的实例
- * @return
- */
- public MsgService getService(){
- return MsgService.this;
- }
- }
- }</span>
- Intent intent = new Intent("com.example.communication.MSG_ACTION");
- bindService(intent, conn, Context.BIND_AUTO_CREATE);
通过上面的代码我们就在Activity绑定了一个Service,上面需要一个ServiceConnection对象,它是一个接口,我们这里使用了匿名内部类
- <span style="font-family:System;"> ServiceConnection conn = new ServiceConnection() {
- @Override
- public void onServiceDisconnected(ComponentName name) {
- }
- @Override
- public void onServiceConnected(ComponentName name, IBinder service) {
- //返回一个MsgService对象
- msgService = ((MsgService.MsgBinder)service).getService();
- }
- };</span>
在onServiceConnected(ComponentName name, IBinder service) 回调方法中,返回了一个MsgService中的Binder对象,我们可以通过getService()方法来得到一个MsgService对象,然后可以调用MsgService中的一些方法,Activity的代码如下
- <span style="font-family:System;">package com.example.communication;
- import android.app.Activity;
- import android.content.ComponentName;
- import android.content.Context;
- import android.content.Intent;
- import android.content.ServiceConnection;
- import android.os.Bundle;
- import android.os.IBinder;
- import android.view.View;
- import android.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.ProgressBar;
- public class MainActivity extends Activity {
- private MsgService msgService;
- private int progress = 0;
- private ProgressBar mProgressBar;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- //绑定Service
- Intent intent = new Intent("com.example.communication.MSG_ACTION");
- bindService(intent, conn, Context.BIND_AUTO_CREATE);
- mProgressBar = (ProgressBar) findViewById(R.id.progressBar1);
- Button mButton = (Button) findViewById(R.id.button1);
- mButton.setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- //开始下载
- msgService.startDownLoad();
- //监听进度
- listenProgress();
- }
- });
- }
- /**
- * 监听进度,每秒钟获取调用MsgService的getProgress()方法来获取进度,更新UI
- */
- public void listenProgress(){
- new Thread(new Runnable() {
- @Override
- public void run() {
- while(progress < MsgService.MAX_PROGRESS){
- progress = msgService.getProgress();
- mProgressBar.setProgress(progress);
- try {
- Thread.sleep(1000);
- } catch (InterruptedException e) {
- e.printStackTrace();
- }
- }
- }
- }).start();
- }
- ServiceConnection conn = new ServiceConnection() {
- @Override
- public void onServiceDisconnected(ComponentName name) {
- }
- @Override
- public void onServiceConnected(ComponentName name, IBinder service) {
- //返回一个MsgService对象
- msgService = ((MsgService.MsgBinder)service).getService();
- }
- };
- @Override
- protected void onDestroy() {
- unbindService(conn);
- super.onDestroy();
- }
- }</span><span style="font-family: simsun;">
- </span>
上面的代码就完成了在Service更新UI的操作,可是你发现了没有,我们每次都要主动调用getProgress()来获取进度值,然后隔一秒在调用一次getProgress()方法,你会不会觉得很被动呢?可不可以有一种方法当Service中进度发生变化主动通知Activity,答案是肯定的,我们可以利用回调接口实现Service的主动通知,不理解回调方法的可以看看http://blog.csdn.net/xiaanming/article/details/8703708
新建一个回调接口
- public interface OnProgressListener {
- void onProgress(int progress);
- }
- <span style="font-family:System;">package com.example.communication;
- import android.app.Service;
- import android.content.Intent;
- import android.os.Binder;
- import android.os.IBinder;
- public class MsgService extends Service {
- /**
- * 进度条的最大值
- */
- public static final int MAX_PROGRESS = 100;
- /**
- * 进度条的进度值
- */
- private int progress = 0;
- /**
- * 更新进度的回调接口
- */
- private OnProgressListener onProgressListener;
- /**
- * 注册回调接口的方法,供外部调用
- * @param onProgressListener
- */
- public void setOnProgressListener(OnProgressListener onProgressListener) {
- this.onProgressListener = onProgressListener;
- }
- /**
- * 增加get()方法,供Activity调用
- * @return 下载进度
- */
- public int getProgress() {
- return progress;
- }
- /**
- * 模拟下载任务,每秒钟更新一次
- */
- public void startDownLoad(){
- new Thread(new Runnable() {
- @Override
- public void run() {
- while(progress < MAX_PROGRESS){
- progress += 5;
- //进度发生变化通知调用方
- if(onProgressListener != null){
- onProgressListener.onProgress(progress);
- }
- try {
- Thread.sleep(1000);
- } catch (InterruptedException e) {
- e.printStackTrace();
- }
- }
- }
- }).start();
- }
- /**
- * 返回一个Binder对象
- */
- @Override
- public IBinder onBind(Intent intent) {
- return new MsgBinder();
- }
- public class MsgBinder extends Binder{
- /**
- * 获取当前Service的实例
- * @return
- */
- public MsgService getService(){
- return MsgService.this;
- }
- }
- }</span>
- <span style="font-family:System;">package com.example.communication;
- import android.app.Activity;
- import android.content.ComponentName;
- import android.content.Context;
- import android.content.Intent;
- import android.content.ServiceConnection;
- import android.os.Bundle;
- import android.os.IBinder;
- import android.view.View;
- import android.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.ProgressBar;
- public class MainActivity extends Activity {
- private MsgService msgService;
- private ProgressBar mProgressBar;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- //绑定Service
- Intent intent = new Intent("com.example.communication.MSG_ACTION");
- bindService(intent, conn, Context.BIND_AUTO_CREATE);
- mProgressBar = (ProgressBar) findViewById(R.id.progressBar1);
- Button mButton = (Button) findViewById(R.id.button1);
- mButton.setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- //开始下载
- msgService.startDownLoad();
- }
- });
- }
- ServiceConnection conn = new ServiceConnection() {
- @Override
- public void onServiceDisconnected(ComponentName name) {
- }
- @Override
- public void onServiceConnected(ComponentName name, IBinder service) {
- //返回一个MsgService对象
- msgService = ((MsgService.MsgBinder)service).getService();
- //注册回调接口来接收下载进度的变化
- msgService.setOnProgressListener(new OnProgressListener() {
- @Override
- public void onProgress(int progress) {
- mProgressBar.setProgress(progress);
- }
- });
- }
- };
- @Override
- protected void onDestroy() {
- unbindService(conn);
- super.onDestroy();
- }
- }
- </span>
- 通过broadcast(广播)的形式
当我们的进度发生变化的时候我们发送一条广播,然后在Activity的注册广播接收器,接收到广播之后更新ProgressBar,代码如下
- package com.example.communication;
- <span style="font-family:System;">
- import android.app.Activity;
- import android.content.BroadcastReceiver;
- import android.content.Context;
- import android.content.Intent;
- import android.content.IntentFilter;
- import android.os.Bundle;
- import android.view.View;
- import android.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.ProgressBar;
- public class MainActivity extends Activity {
- private ProgressBar mProgressBar;
- private Intent mIntent;
- private MsgReceiver msgReceiver;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- //动态注册广播接收器
- msgReceiver = new MsgReceiver();
- IntentFilter intentFilter = new IntentFilter();
- intentFilter.addAction("com.example.communication.RECEIVER");
- registerReceiver(msgReceiver, intentFilter);
- mProgressBar = (ProgressBar) findViewById(R.id.progressBar1);
- Button mButton = (Button) findViewById(R.id.button1);
- mButton.setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- //启动服务
- mIntent = new Intent("com.example.communication.MSG_ACTION");
- startService(mIntent);
- }
- });
- }
- @Override
- protected void onDestroy() {
- //停止服务
- stopService(mIntent);
- //注销广播
- unregisterReceiver(msgReceiver);
- super.onDestroy();
- }
- /**
- * 广播接收器
- * @author len
- *
- */
- public class MsgReceiver extends BroadcastReceiver{
- @Override
- public void onReceive(Context context, Intent intent) {
- //拿到进度,更新UI
- int progress = intent.getIntExtra("progress", 0);
- mProgressBar.setProgress(progress);
- }
- }
- }
- </span>
- <span style="font-family:System;">package com.example.communication;
- import android.app.Service;
- import android.content.Intent;
- import android.os.IBinder;
- public class MsgService extends Service {
- /**
- * 进度条的最大值
- */
- public static final int MAX_PROGRESS = 100;
- /**
- * 进度条的进度值
- */
- private int progress = 0;
- private Intent intent = new Intent("com.example.communication.RECEIVER");
- /**
- * 模拟下载任务,每秒钟更新一次
- */
- public void startDownLoad(){
- new Thread(new Runnable() {
- @Override
- public void run() {
- while(progress < MAX_PROGRESS){
- progress += 5;
- //发送Action为com.example.communication.RECEIVER的广播
- intent.putExtra("progress", progress);
- sendBroadcast(intent);
- try {
- Thread.sleep(1000);
- } catch (InterruptedException e) {
- e.printStackTrace();
- }
- }
- }
- }).start();
- }
- @Override
- public int onStartCommand(Intent intent, int flags, int startId) {
- startDownLoad();
- return super.onStartCommand(intent, flags, startId);
- }
- @Override
- public IBinder onBind(Intent intent) {
- return null;
- }
- }</span>
- Activity调用bindService (Intent service, ServiceConnection conn, int flags)方法,得到Service对象的一个引用,这样Activity可以直接调用到Service中的方法,如果要主动通知Activity,我们可以利用回调方法
- Service向Activity发送消息,可以使用广播,当然Activity要注册相应的接收器。比如Service要向多个Activity发送同样的消息的话,用这种方法就更好
posted on 2015-02-13 11:08 qingchen1984 阅读(190) 评论(0) 编辑 收藏 举报