我需要在所有活动中都有背景音乐。当应用程序不在前台时,它应该停止。由于我正在为 2.3 开发,因此我无法使用 ActivityLifeCycleCallBacks 类。我在检查Android应用程序是否在后台运行时实现了该解决方案,然后决定将媒体播放器设置为单例并在服务中使用它。
一切正常,如果我按主页,从菜单中选择退出,或者我让应用程序以任何声音停止的方式进入后台,但是......在我做其他事情的一段时间后,甚至当屏幕关闭时,音乐会突然再次开始。即使我从任务管理器中杀死应用程序,稍后也会再次启动。
这是我的第一个单身人士,也是我第一次玩服务,所以我想我错过了一些非常基本的东西。我想我正在关闭服务,但显然我没有。这是代码:
播放音频.java
import ...
public class PlayAudio extends Service{
private static final Intent Intent = null;
MediaPlayer objPlayer;
private int length = 0;
boolean mIsPlayerRelease = true;
private static PlayAudio uniqueIstance; //the singleton
static PlayAudio mService;
static boolean mBound = false; // boolean to check if the service containing this singleton is binded to some activity
public static boolean activityVisible; // boolean to check if the activity using the player is foreground or not
//My attempt to make a singleton
public static PlayAudio getUniqueIstance(){
if (uniqueIstance == null) {
uniqueIstance = new PlayAudio();
}
return uniqueIstance;
}
public static boolean isActivityVisible() {
return activityVisible;
}
public static void activityResumed() {
activityVisible = true;
}
public static void activityPaused() {
activityVisible = false;
}
static public ServiceConnection mConnection = new ServiceConnection() {// helper for the activity
public void onServiceConnected(ComponentName className,
IBinder service) {
LocalBinder binder = (LocalBinder) service;
mService = binder.getService();
mBound = true;
}
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
public static Intent createIntent (Context context) { //helper for the activity using the player
Intent intent = new Intent(context, PlayAudio.class);
return intent;
}
private final IBinder mBinder = new LocalBinder();
public class LocalBinder extends Binder {
PlayAudio getService() {
// Return this instance so clients can call public methods
return PlayAudio.this;
}
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
public void onCreate(){
super.onCreate();
Log.d(LOGCAT, "Service Started!");
objPlayer = MediaPlayer.create(this,R.raw.kickstarterreduced);
objPlayer.setLooping(true);
mIsPlayerRelease = false;
}
public int onStartCommand(Intent intent, int flags, int startId){
objPlayer.start();
Log.d(LOGCAT, "Media Player started!");
if(objPlayer.isLooping() != true){
Log.d(LOGCAT, "Problem in Playing Audio");
}
return 1;
}
public void onStop(){
objPlayer.setLooping(false);
objPlayer.stop();
objPlayer.release();
mIsPlayerRelease = true;
}
public void onPause(){
if(objPlayer.isPlaying())
{
objPlayer.pause();
length=objPlayer.getCurrentPosition(); // save the position in order to be able to resume from here
}
}
public void resumeMusic() // if length is 0 the player just start from zero
{ if (mIsPlayerRelease == true) {
objPlayer = MediaPlayer.create(this,R.raw.kickstarterreduced);
mIsPlayerRelease = false;
}
if(objPlayer.isPlaying()==false )
{
if (length != 0) objPlayer.seekTo(length);
objPlayer.start();
}
}
}
这是我在每个活动的类中实现的方法
SharedPreferences sharedPrefs;
PlayAudio playerIstanced;
public static boolean activityVisible;
@Override
public void onStart() {
super.onStart();
sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
}
@Override
public void onResume() {
super.onResume();
playerIstanced= PlayAudio.getUniqueIstance(); //call singleton
bindService(PlayAudio.createIntent(this), playerIstanced.mConnection, Context.BIND_AUTO_CREATE); // create the service
if (sharedPrefs.getBoolean("sound", true) == true) {// if sound is enabled in option it will start the service
startService(PlayAudio.createIntent(this));
playerIstanced.mService.activityResumed();
if (playerIstanced.mBound == true) {
playerIstanced.mService.resumeMusic();
}
}
}
@Override
public void onPause() {
super.onPause();
playerIstanced.mService.activityPaused();
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
public void run() {
//If the phone lags when changing activity (between onPause() and the other activity onResume() the music won't stop. If after 500ms onResume() is not called it means the activity went background...Am I messing with service here?
if (playerIstanced.mService.isActivityVisible() != true) {
playerIstanced.mService.onPause();
}
}
}, 500);
}
@Override
public void onStop(){
super.onStop();
// Unbind from the service
if (playerIstanced.mService.mBound) {
playerIstanced.mService.mBound = false;
unbindService(playerIstanced.mService.mConnection);
}
}
}
用户退出应用时自动停止音乐
这部分必须在每个活动的暂停中:
public void onPause(){
super.onPause();
Context context = getApplicationContext();
ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningTaskInfo> taskInfo = am.getRunningTasks(1);
if (!taskInfo.isEmpty()) {
ComponentName topActivity = taskInfo.get(0).topActivity;
if (!topActivity.getPackageName().equals(context.getPackageName())) {
StopPlayer();
Toast.makeText(xYourClassNamex.this, "YOU LEFT YOUR APP. MUSIC STOP", Toast.LENGTH_SHORT).show();
}
}
}
这部分必须在每个活动的简历中:
用户恢复应用时自动播放音乐
Public void onResume()
{
super.onResume();
StartPlayer();
}
希望对您有所帮助!!您可以根据此主题检查我的答案,但愿它能解决您的问题。
使用 Context.stopService() 或 stopSelf() 手动停止服务。请参阅 http://developer.android.com/reference/android/app/Service.html 的服务生命周期部分。
服务生命周期
系统可以运行服务有两个原因。如果有人调用 Context.startService(),那么系统将检索该服务(如果需要,创建它并调用其 onCreate() 方法),然后使用客户端提供的参数调用其 onStartCommand(Intent, int, int) 方法。此时,该服务将继续运行,直到调用 Context.stopService() 或 stopSelf()。请注意,对 Context.startService() 的多次调用不会嵌套(尽管它们确实会导致对 onStartCommand() 的多次相应调用),因此无论启动多少次,一旦调用 Context.stopService() 或 stopSelf(),服务就会停止;但是,服务可以使用其 stopSelf(int) 方法来确保在处理启动的意图之前不会停止服务。
我相信你可以简单地将playerIstanced.stopSelf()放在每个活动的onStop()调用中。
我的理解是,在您的应用程序停止后,该服务将继续安静运行。一段时间后,系统会终止服务以释放资源,然后在一段时间后,当资源可用时,它会重新启动服务。当服务重新启动其 onResume() 时,将调用音乐并开始播放。
它帮助我停止了媒体播放器。使用 Handler(getMainLooper()) 启动和停止 MediaPlayer。
final Handler handler = new Handler(getMainLooper());
handler.post(new Runnable() {
@Override
public void run() {
mediaPlayer.start();
}
});
handler.postDelayed(new Runnable() {
@Override
public void run() {
if (mediaPlayer.isPlaying()) {
mediaPlayer.stop();
}
}
, 30 * 1000);