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public class WeiboService extends Service{                        //用于判断微博是否有更新标志        private boolean newDateFlag = false;                //微博对象        Weibo weibo;                NotificationManager m_NotificationManager;          Notification m_Notification;          PendingIntent m_PendingIntent;                  //继承自BroadcastReceiver对象，用于得到Activity发送过来的命令    CommandReceiver cmdReceiver;    boolean flag;        //Service命令列表    int CMD_STOP_SERVICE = 0;    int CMD_RESET_SERVICE = 1;    int CMD_GET_WEIBO_DATA = 2;    @Override    public void onCreate() {//重写onCreate方法        flag = true;        //初始化新浪weibo open api         System.setProperty("weibo4j.oauth.consumerKey", Weibo.CONSUMER_KEY);            System.setProperty("weibo4j.oauth.consumerSecret", Weibo.CONSUMER_SECRET);        weibo=OAuthConstant.getInstance().getWeibo();        //注册时，新浪给你的两个字符串，填写上去        weibo.setToken("xxxxxx", "xxxxxxxx");                m_Notification = new Notification();                super.onCreate();            }        @Override    public IBinder onBind(Intent intent) {//重写onBind方法        // TODO Auto-generated method stub        return null;    }        //前台Activity调用startService时，该方法自动执行    @Override    public int onStartCommand(Intent intent, int flags, int startId) {//重写onStartCommand方法            cmdReceiver = new CommandReceiver();        IntentFilter filter = new IntentFilter();//创建IntentFilter对象        //注册一个广播，用于接收Activity传送过来的命令，控制Service的行为，如：发送数据，停止服务等        //字符串：weibo4andriod.focusme.weiboService为自定义，没有什么要求，一般用包名+文件名，避免重复        //如果重复，Android系统在运行期会显示一个接收相同Action的服务程序列表，供用户选择。        //注册同一个action的程序，能否同时接收广播，待测试.....        filter.addAction("weibo4andriod.focusme.weiboService");        //注册Broadcast Receiver        registerReceiver(cmdReceiver, filter);        doJob();//调用方法启动线程        return super.onStartCommand(intent, flags, startId);    }    //方法：    public void doJob(){        new Thread(){            public void run(){                                        ArrayList<HashMap<String,String>> data;                while(flag){                    try{//睡眠一段时间                            Thread.sleep(5000);                    }                    catch(Exception e){                            e.printStackTrace();                    }                                        data = getWeiboData();                                        if(isNewDateFlag()){                        sendNotification("xxxxxxxxx");                                            }                     setNewDateFlag(false);                }                                            }        }.start();    }     //接收Activity传送过来的命令    private class CommandReceiver extends BroadcastReceiver{        @Override        public void onReceive(Context context, Intent intent) {            int cmd = intent.getIntExtra("cmd", -1);//获取Extra信息                        if(cmd == CMD_STOP_SERVICE){//如果发来的消息是停止服务                                                    flag = false;//停止线程                    stopSelf();//停止服务                        }                  if(cmd == CMD_RESET_SERVICE){//如果发来的消息是刷新服务                                                       }            if(cmd == CMD_GET_WEIBO_DATA){//如果发来的消息是发送weibo数据                                                    sendWeiboData();              }        }                                  }    @Override    public void onDestroy() {//重写onDestroy方法        this.unregisterReceiver(cmdReceiver);//取消注册的CommandReceiver        super.onDestroy();    }          /*     * Get Weibo data     */    public ArrayList<HashMap<String,String>> getWeiboData(){                        ArrayList<HashMap<String,String>> weiboDataList                                     = new ArrayList<HashMap<String,String>>();                            HashMap<String, String> map                                         = new HashMap<String, String>();                List<Status> friendsTimeline;                                try {                        friendsTimeline = weibo.getUserTimeline();                                                for (Status status : friendsTimeline) {                                                                ofCheckNewWeibo(status.getCreatedAt());                                                                map = new HashMap<String, String>();                          map.put("CreatedAt", status.getCreatedAt().toString());                          map.put("WeiBoText", status.getText());                                              weiboDataList.add(map);                        }                        }                catch (WeiboException e) {                        e.printStackTrace();                }                return weiboDataList;     }        private void ofCheckNewWeibo(Date createdAt) {                // TODO Auto-generated method stub            Date weibolastdate;            Editor editor;                        //通过SharedPreFerence读取和记录系统配置信息            SharedPreferences preferences = getSharedPreferences("weiboDate",Context.MODE_PRIVATE);                        weibolastdate = SParseD(preferences.getString("lastDate","Mon Nov 29 16:08:43 +0800 1900"));                if(weibolastdate.before(createdAt)){                                                editor = preferences.edit();                             editor.putString("lastDate", createdAt.toString());                             editor.commit();                        setNewDateFlag(true);                }        }        /**     * 发送有微博更新的通知     * @param sendText     */    public void sendNotification(String sendText){                        Intent intent = new Intent(WeiboService.this,AndriodFocusMe.class);                    m_Notification.icon=R.drawable.icon;             m_Notification.tickerText=sendText;             m_Notification.defaults=Notification.DEFAULT_SOUND;                          m_PendingIntent=PendingIntent.getActivity(WeiboService.this, 0,intent, 0);             m_Notification.setLatestEventInfo(WeiboService.this, "title", "text",m_PendingIntent);            m_NotificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);            m_NotificationManager.notify(R.id.TextView01,m_Notification);      }                    /**     * String to Date     * @param date     * @return     */     //比较数据是否为新的    public Date SParseD(String date){            String format = "EEE MMM dd HH:mm:ss Z yyyy";        SimpleDateFormat dateFormat = new SimpleDateFormat(format, Locale.US);                Date parseDate = null;                try {                        parseDate = dateFormat.parse(date);                } catch (ParseException e) {                        // TODO Auto-generated catch block                        e.printStackTrace();                }                return parseDate;    }        public boolean isNewDateFlag() {                return newDateFlag;        }        public void setNewDateFlag(boolean newDateFlag) {                this.newDateFlag = newDateFlag;        }                        //发送微博数据列表        public void sendWeiboData() {                // TODO Auto-generated method stub                ArrayList<HashMap<String,String>> Data;                Data = getWeiboData();                                Intent intent = new Intent();//创建Intent对象                    Bundle bundle = new Bundle();            //序列化列表，发送后在本地重建数据            bundle.putSerializable("weibodata",Data);            intent.setAction("weiboDataChanged");        intent.putExtras(bundle);        sendBroadcast(intent);//发送广播                        }}

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();        }}

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。