service的使用

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src\com.exampleservice\MainActivity.java:
package com.exampleservice;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.Handler;import android.os.IBinder;import android.os.Message;import android.os.Messenger;import android.os.RemoteException;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class MainActivity extends Activity {    Button btnStart, btnStop, btnBind, btnUnbind, btnUpby1, btnUpby10;    TextView textStatus, textIntValue, textStrValue;    Messenger mService = null;    boolean mIsBound;    final Messenger mMessenger = new Messenger(new IncomingHandler());    class IncomingHandler extends Handler {        @Override        public void handleMessage(Message msg) {            switch (msg.what) {            case MyService.MSG_SET_INT_VALUE:                textIntValue.setText("Int Message: " + msg.arg1);                break;            case MyService.MSG_SET_STRING_VALUE:                String str1 = msg.getData().getString("str1");                textStrValue.setText("Str Message: " + str1);                break;            default:                super.handleMessage(msg);            }        }    }    private ServiceConnection mConnection = new ServiceConnection() {        public void onServiceConnected(ComponentName className, IBinder service) {            mService = new Messenger(service);            textStatus.setText("Attached.");            try {                Message msg = Message.obtain(null, MyService.MSG_REGISTER_CLIENT);                msg.replyTo = mMessenger;                mService.send(msg);            } catch (RemoteException e) {                // In this case the service has crashed before we could even do anything with it            }        }        public void onServiceDisconnected(ComponentName className) {            // This is called when the connection with the service has been unexpectedly disconnected - process crashed.            mService = null;            textStatus.setText("Disconnected.");        }    };    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        btnStart = (Button)findViewById(R.id.btnStart);        btnStop = (Button)findViewById(R.id.btnStop);        btnBind = (Button)findViewById(R.id.btnBind);        btnUnbind = (Button)findViewById(R.id.btnUnbind);        textStatus = (TextView)findViewById(R.id.textStatus);        textIntValue = (TextView)findViewById(R.id.textIntValue);        textStrValue = (TextView)findViewById(R.id.textStrValue);        btnUpby1 = (Button)findViewById(R.id.btnUpby1);        btnUpby10 = (Button)findViewById(R.id.btnUpby10);        btnStart.setOnClickListener(btnStartListener);        btnStop.setOnClickListener(btnStopListener);        btnBind.setOnClickListener(btnBindListener);        btnUnbind.setOnClickListener(btnUnbindListener);        btnUpby1.setOnClickListener(btnUpby1Listener);        btnUpby10.setOnClickListener(btnUpby10Listener);        restoreMe(savedInstanceState);        CheckIfServiceIsRunning();    }    @Override    protected void onSaveInstanceState(Bundle outState) {        super.onSaveInstanceState(outState);        outState.putString("textStatus", textStatus.getText().toString());        outState.putString("textIntValue", textIntValue.getText().toString());        outState.putString("textStrValue", textStrValue.getText().toString());    }    private void restoreMe(Bundle state) {        if (state!=null) {            textStatus.setText(state.getString("textStatus"));            textIntValue.setText(state.getString("textIntValue"));            textStrValue.setText(state.getString("textStrValue"));        }    }    private void CheckIfServiceIsRunning() {        //If the service is running when the activity starts, we want to automatically bind to it.        if (MyService.isRunning()) {            doBindService();        }    }    private OnClickListener btnStartListener = new OnClickListener() {        public void onClick(View v){            startService(new Intent(MainActivity.this, MyService.class));        }    };    private OnClickListener btnStopListener = new OnClickListener() {        public void onClick(View v){            doUnbindService();            stopService(new Intent(MainActivity.this, MyService.class));        }    };    private OnClickListener btnBindListener = new OnClickListener() {        public void onClick(View v){            doBindService();        }    };    private OnClickListener btnUnbindListener = new OnClickListener() {        public void onClick(View v){            doUnbindService();        }    };    private OnClickListener btnUpby1Listener = new OnClickListener() {        public void onClick(View v){            sendMessageToService(1);        }    };    private OnClickListener btnUpby10Listener = new OnClickListener() {        public void onClick(View v){            sendMessageToService(10);        }    };    private void sendMessageToService(int intvaluetosend) {        if (mIsBound) {            if (mService != null) {                try {                    Message msg = Message.obtain(null, MyService.MSG_SET_INT_VALUE, intvaluetosend, 0);                    msg.replyTo = mMessenger;                    mService.send(msg);                } catch (RemoteException e) {                }            }        }    }    void doBindService() {        bindService(new Intent(this, MyService.class), mConnection, Context.BIND_AUTO_CREATE);        mIsBound = true;        textStatus.setText("Binding.");    }    void doUnbindService() {        if (mIsBound) {            // If we have received the service, and hence registered with it, then now is the time to unregister.            if (mService != null) {                try {                    Message msg = Message.obtain(null, MyService.MSG_UNREGISTER_CLIENT);                    msg.replyTo = mMessenger;                    mService.send(msg);                } catch (RemoteException e) {                    // There is nothing special we need to do if the service has crashed.                }            }            // Detach our existing connection.            unbindService(mConnection);            mIsBound = false;            textStatus.setText("Unbinding.");        }    }    @Override    protected void onDestroy() {        super.onDestroy();        try {            doUnbindService();        } catch (Throwable t) {            Log.e("MainActivity", "Failed to unbind from the service", t);        }    }}
src\com.exampleservice\MyService.java:
package com.exampleservice;import java.util.ArrayList;import java.util.Timer;import java.util.TimerTask;import android.app.Notification;import android.app.NotificationManager;import android.app.PendingIntent;import android.app.Service;import android.content.Intent;import android.os.Bundle;import android.os.Handler;import android.os.IBinder;import android.os.Message;import android.os.Messenger;import android.os.RemoteException;import android.util.Log;public class MyService extends Service {    private NotificationManager nm;    private Timer timer = new Timer();    private int counter = 0, incrementby = 1;    private static boolean isRunning = false;    ArrayList<Messenger> mClients = new ArrayList<Messenger>(); // Keeps track of all current registered clients.    int mValue = 0; // Holds last value set by a client.    static final int MSG_REGISTER_CLIENT = 1;    static final int MSG_UNREGISTER_CLIENT = 2;    static final int MSG_SET_INT_VALUE = 3;    static final int MSG_SET_STRING_VALUE = 4;    final Messenger mMessenger = new Messenger(new IncomingHandler()); // Target we publish for clients to send messages to IncomingHandler.    @Override    public IBinder onBind(Intent intent) {        return mMessenger.getBinder();    }    class IncomingHandler extends Handler { // Handler of incoming messages from clients.        @Override        public void handleMessage(Message msg) {            switch (msg.what) {            case MSG_REGISTER_CLIENT:                mClients.add(msg.replyTo);                break;            case MSG_UNREGISTER_CLIENT:                mClients.remove(msg.replyTo);                break;            case MSG_SET_INT_VALUE:                incrementby = msg.arg1;                break;            default:                super.handleMessage(msg);            }        }    }    private void sendMessageToUI(int intvaluetosend) {        for (int i=mClients.size()-1; i>=0; i--) {            try {                // Send data as an Integer                mClients.get(i).send(Message.obtain(null, MSG_SET_INT_VALUE, intvaluetosend, 0));                //Send data as a String                Bundle b = new Bundle();                b.putString("str1", "ab" + intvaluetosend + "cd");                Message msg = Message.obtain(null, MSG_SET_STRING_VALUE);                msg.setData(b);                mClients.get(i).send(msg);            } catch (RemoteException e) {                // The client is dead. Remove it from the list; we are going through the list from back to front so this is safe to do inside the loop.                mClients.remove(i);            }        }    }    @Override    public void onCreate() {        super.onCreate();        Log.i("MyService", "Service Started.");        showNotification();        timer.scheduleAtFixedRate(new TimerTask(){ public void run() {onTimerTick();}}, 0, 100L);        isRunning = true;    }    private void showNotification() {        nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);        // In this sample, we'll use the same text for the ticker and the expanded notification        CharSequence text = getText(R.string.service_started);        // Set the icon, scrolling text and timestamp        Notification notification = new Notification(R.drawable.icon, text, System.currentTimeMillis());        // The PendingIntent to launch our activity if the user selects this notification        PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);        // Set the info for the views that show in the notification panel.        notification.setLatestEventInfo(this, getText(R.string.service_label), text, contentIntent);        // Send the notification.        // We use a layout id because it is a unique number.  We use it later to cancel.        nm.notify(R.string.service_started, notification);    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Log.i("MyService", "Received start id " + startId + ": " + intent);        return START_STICKY; // run until explicitly stopped.    }    public static boolean isRunning()    {        return isRunning;    }    private void onTimerTick() {        Log.i("TimerTick", "Timer doing work." + counter);        try {            counter += incrementby;            sendMessageToUI(counter);        } catch (Throwable t) { //you should always ultimately catch all exceptions in timer tasks.            Log.e("TimerTick", "Timer Tick Failed.", t);                    }    }    @Override    public void onDestroy() {        super.onDestroy();        if (timer != null) {timer.cancel();}        counter=0;        nm.cancel(R.string.service_started); // Cancel the persistent notification.        Log.i("MyService", "Service Stopped.");        isRunning = false;    }}