The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...
/*
* Copyright (C) 2009 The Android开源工程
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.apis.app;
import android.app.Activity;
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.IBinder;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
// Need the following import to get access to the app resources, since this
// class is in a sub-package.
import com.example.android.apis.R;
/**
* This is an example of implementing an application service that can
* run in the "foreground". It shows how to code this to work well by using
* the improved Android 2.0 APIs when available and otherwise falling back
* to the original APIs. Yes: you can take this exact code, compile it
* against the Android 2.0 SDK, and it will against everything down to
* Android 1.0.
*/
public class ForegroundService extends Service {
static final String ACTION_FOREGROUND = "com.example.android.apis.FOREGROUND";
static final String ACTION_BACKGROUND = "com.example.android.apis.BACKGROUND";
private static final Class<?>[] mSetForegroundSignature = new Class[] {
boolean.class};
private static final Class<?>[] mStartForegroundSignature = new Class[] {
int.class, Notification.class};
private static final Class<?>[] mStopForegroundSignature = new Class[] {
boolean.class};
private NotificationManager mNM;
private Method mSetForeground;
private Method mStartForeground;
private Method mStopForeground;
private Object[] mSetForegroundArgs = new Object[1];
private Object[] mStartForegroundArgs = new Object[2];
private Object[] mStopForegroundArgs = new Object[1];
void invokeMethod(Method method, Object[] args) {
try {
method.invoke(this, args);
} catch (InvocationTargetException e) {
// Should not happen.
Log.w("ApiDemos", "Unable to invoke method", e);
} catch (IllegalAccessException e) {
// Should not happen.
Log.w("ApiDemos", "Unable to invoke method", e);
}
}
/**
* This is a wrapper around the new startForeground method, using the older
* APIs if it is not available.
*/
void startForegroundCompat(int id, Notification notification) {
// If we have the new startForeground API, then use it.
if (mStartForeground != null) {
mStartForegroundArgs[0] = Integer.valueOf(id);
mStartForegroundArgs[1] = notification;
invokeMethod(mStartForeground, mStartForegroundArgs);
return;
}
// Fall back on the old API.
mSetForegroundArgs[0] = Boolean.TRUE;
invokeMethod(mSetForeground, mSetForegroundArgs);
mNM.notify(id, notification);
}
/**
* This is a wrapper around the new stopForeground method, using the older
* APIs if it is not available.
*/
void stopForegroundCompat(int id) {
// If we have the new stopForeground API, then use it.
if (mStopForeground != null) {
mStopForegroundArgs[0] = Boolean.TRUE;
invokeMethod(mStopForeground, mStopForegroundArgs);
return;
}
// Fall back on the old API. Note to cancel BEFORE changing the
// foreground state, since we could be killed at that point.
mNM.cancel(id);
mSetForegroundArgs[0] = Boolean.FALSE;
invokeMethod(mSetForeground, mSetForegroundArgs);
}
@Override
public void onCreate() {
mNM = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
try {
mStartForeground = getClass().getMethod("startForeground",
mStartForegroundSignature);
mStopForeground = getClass().getMethod("stopForeground",
mStopForegroundSignature);
return;
} catch (NoSuchMethodException e) {
// Running on an older platform.
mStartForeground = mStopForeground = null;
}
try {
mSetForeground = getClass().getMethod("setForeground",
mSetForegroundSignature);
} catch (NoSuchMethodException e) {
throw new IllegalStateException(
"OS doesn't have Service.startForeground OR Service.setForeground!");
}
}
@Override
public void onDestroy() {
// Make sure our notification is gone.
stopForegroundCompat(R.string.foreground_service_started);
}
// This is the old onStart method that will be called on the pre-2.0
// platform. On 2.0 or later we override onStartCommand() so this
// method will not be called.
@Override
public void onStart(Intent intent, int startId) {
handleCommand(intent);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
handleCommand(intent);
// We want this service to continue running until it is explicitly
// stopped, so return sticky.
return START_STICKY;
}
void handleCommand(Intent intent) {
if (ACTION_FOREGROUND.equals(intent.getAction())) {
// In this sample, we'll use the same text for the ticker and the expanded notification
CharSequence text = getText(R.string.foreground_service_started);
// Set the icon, scrolling text and timestamp
Notification notification = new Notification(R.drawable.stat_sample, text,
System.currentTimeMillis());
// The PendingIntent to launch our activity if the user selects this notification
PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
new Intent(this, Controller.class), 0);
// Set the info for the views that show in the notification panel.
notification.setLatestEventInfo(this, getText(R.string.local_service_label),
text, contentIntent);
startForegroundCompat(R.string.foreground_service_started, notification);
} else if (ACTION_BACKGROUND.equals(intent.getAction())) {
stopForegroundCompat(R.string.foreground_service_started);
}
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
// ----------------------------------------------------------------------
/**
* <p>Example of explicitly starting and stopping the {@link ForegroundService}.
*
* <p>Note that this is implemented as an inner class only keep the sample
* all together; typically this code would appear in some separate class.
*/
public static class Controller extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.foreground_service_controller);
// Watch for button clicks.
Button button = (Button)findViewById(R.id.start_foreground);
button.setOnClickListener(mForegroundListener);
button = (Button)findViewById(R.id.start_background);
button.setOnClickListener(mBackgroundListener);
button = (Button)findViewById(R.id.stop);
button.setOnClickListener(mStopListener);
}
private OnClickListener mForegroundListener = new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(ForegroundService.ACTION_FOREGROUND);
intent.setClass(Controller.this, ForegroundService.class);
startService(intent);
}
};
private OnClickListener mBackgroundListener = new OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(ForegroundService.ACTION_BACKGROUND);
intent.setClass(Controller.this, ForegroundService.class);
startService(intent);
}
};
private OnClickListener mStopListener = new OnClickListener() {
public void onClick(View v) {
stopService(new Intent(Controller.this,
ForegroundService.class));
}
};
}
}