Activity与Service通过广播交换复杂对象数据用法详解

最近学习新浪微博开放平台，实现了一个应用，通过后台Service监控微博数据，发现数据更新后通知前台程序，并将博客数据列表发送给前台Activity。

其中利用BroadcastReceiver对象分别在Activity和Service注册了一个广播，通过发送不同的广播控制前台和后台的数据交换，并通过Serializable对象传递复杂的自定义对象类型给Activity。

程序片段如下：后台监控weibo Service

//继承自Service的子类

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AndriodFocusMe 主UI界面Activity

public class AndriodFocusMe extends Activity implements Runnable{

/** Called when the activity is first created. */

DataReceiver dataReceiver;//BroadcastReceiver对象

ProgressBar progressbar;

ListView listview;

int CMD_STOP_SERVICE = 0;

int CMD_RESET_SERVICE = 1;

int CMD_GET_WEIBO_DATA = 2;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.weibodataview);

Button beginOuathBtn= (Button) findViewById(R.id.Button_WeiBo);

Button endBtn = (Button) findViewById(R.id.flashData);

listview = (ListView)findViewById(R.id.weibodatalist);

progressbar = (ProgressBar)findViewById(R.id.wbprogressbar);

progressbar.setVisibility(View.INVISIBLE);

beginOuathBtn.setOnClickListener(new Button.OnClickListener()

{

@Override

public void onClick( View v )

{

Intent myIntent = new Intent(AndriodFocusMe.this, WeiboService.class);

AndriodFocusMe.this.startService(myIntent);//发送Intent启动Service

progressbar.setVisibility(View.VISIBLE);

}

} );

endBtn.setOnClickListener(new Button.OnClickListener()

{

@Override

public void onClick( View v )

{

Intent intent = new Intent();//创建Intent对象

intent.setAction("weibo4andriod.focusme.weiboService");

intent.putExtra("cmd", CMD_GET_WEIBO_DATA);

sendBroadcast(intent);//发送广播

}

} );

}

private class DataReceiver extends BroadcastReceiver{//继承自BroadcastReceiver的子类

ArrayList<HashMap<String, String>> weibodatalist;

@Override

public void onReceive(Context context, Intent intent) {//重写onReceive方法

try {

Bundle bundle = intent.getExtras();

//反序列化，在本地重建数据

Serializable data = bundle.getSerializable("weibodata");

if (data != null) {

weibodatalist = (ArrayList<HashMap<String, String>>)data;

SimpleAdapter mSchedule = new SimpleAdapter(AndriodFocusMe.this,weibodatalist,

R.layout.weibodata_itemview,

new String[] {"CreatedAt", "WeiBoText"},

new int[] {R.id.title,R.id.weibotext});

listview.setAdapter(mSchedule);

} else {

return;

}

} catch (Exception e) {

Log.v("test", e.toString());

}

progressbar.setVisibility(View.GONE);

}

}

@Override

protected void onStart() {//重写onStart方法

//注册用于接收Service传送的广播

dataReceiver = new DataReceiver();

IntentFilter filter = new IntentFilter();//创建IntentFilter对象

filter.addAction("weiboDataChanged");

registerReceiver(dataReceiver, filter);//注册Broadcast Receiver

NotificationManager m_NotificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

m_NotificationManager.cancel(R.id.TextView01);

super.onStart();

}

@Override

protected void onStop() {//重写onStop方法

unregisterReceiver(dataReceiver);

finish();

super.onStop();

}

}

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通过这个例子，基本可以掌握Android常用组件的用法，希望能给各位读者带来帮助，并欢迎提出宝贵意见。