我的应用音乐播放存在问题。我在一个服务类中设置了媒体播放器，它可以在整个应用程序中播放音乐。但是，我遇到的问题是将屏幕从“选项”页面再次更改为主页时。
在选项类中，我有一个ToggleButton可以在单击时打开和关闭音乐，我使用布尔值来确定ToggleButton是否自动开启和关闭，具体取决于关于音乐是否在播放。
然而，当用户点击后退按钮或保存按钮（它们都将它们发送回主页）时，音乐会再次开始播放，即使它被选中为“关闭”。
有人对我有建议吗？
服务类：
public class MyMusicService extends Service {
MediaPlayer mp;
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
mp = MediaPlayer.create(this, R.raw.song);
mp.start();
mp.setLooping(true);
return super.onStartCommand(intent, flags, startId);
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onDestroy() {
super.onDestroy();
if(mp!=null) {
mp.stop();
mp.release();
}
mp=null;
}
}
选项类：
public class OptionsActivity extends Activity {
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK ) {
Intent i = new Intent(OptionsActivity.this, MainActivity.class);
startActivity(i);
return true;
}
return super.onKeyDown(keyCode, event);
}
private boolean isMyServiceRunning(String serviceCanonicalClassName) {
ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
if (serviceCanonicalClassName.equals(service.service.getClassName())) {
return true;
}
}
return false;
}
Intent i; // Handles MyMusicService.java
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.options);
final TextView tSound = (TextView) findViewById(R.id.textView2);
final Button saveBtn = (Button) findViewById(R.id.optSaveBtn);
final Button tblBtn = (Button) findViewById(R.id.tableBtn);
i=new Intent(this, MyMusicService.class);
final ToggleButton soundOption = (ToggleButton) findViewById(R.id.soundPref);
boolean musicPlays = isMyServiceRunning(MyMusicService.class.getCanonicalName());
soundOption.setChecked(musicPlays);
if(musicPlays==true){
tSound.setText("On");
}
if(musicPlays==false) {
tSound.setText("Off");
}
soundOption.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on clicks to control sound being on and off.
if(soundOption.isChecked()) {
Toast.makeText(OptionsActivity.this, "Music on.", Toast.LENGTH_SHORT).show();
startService(i);
Intent i = new Intent(OptionsActivity.this, OptionsActivity.class);
startActivity(i);
}
else {
if(stopService(i)==true){
soundOption.setChecked(false);
stopService(i);
Toast.makeText(OptionsActivity.this, "Music off.", Toast.LENGTH_SHORT).show();
Intent i = new Intent(OptionsActivity.this, OptionsActivity.class);
startActivity(i);
}
}
}
});
tblBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent tblView = new Intent(OptionsActivity.this, SQLView.class);
startActivity(tblView);
}
});
saveBtn.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
Intent homePage = new Intent(OptionsActivity.this, MainActivity.class);
switch (v.getId()){
case R.id.optSaveBtn: //Determine what will happen when the user presses the "Submit button".
boolean optionsWork = true;
try{
String sound = tSound.getText().toString();
optionsDB entry = new optionsDB(OptionsActivity.this); //Creating a new instance of MasterMind game
entry.open();
entry.createOptionEntry(sound); //Passing both strings
entry.close();
}catch (Exception e){ //Creating an error message if for some reason the app cannot transfer data to the Database.
Toast.makeText(OptionsActivity.this, "Error", Toast.LENGTH_SHORT).show();
}
finally { //Creating an AlertDialog box when the user presses the Submit button.
if (optionsWork){
Toast.makeText(OptionsActivity.this, "Settings Saved", Toast.LENGTH_SHORT).show();
}
}
break;
}
startActivity(homePage);
}
});
}
}
最后，家庭班：
public class MainActivity extends Activity {
Intent i;
private boolean isMyServiceRunning(String serviceCanonicalClassName) {
ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
if (serviceCanonicalClassName.equals(service.service.getClassName())) {
return true;
}
}
return false;
}
public void checkSound(){
boolean musicPlays = isMyServiceRunning(MyMusicService.class.getCanonicalName());
if(musicPlays==true){
//Do nothing
}
else {
stopService(i);
}
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//setting the layout
//Start Networking
//Intent net = new Intent(this, Networking.class);
//startService(net);
//Auto starts playing music on app launch.
i = new Intent(this,MyMusicService.class);
startService(i);
checkSound();
final ImageView findGame = (ImageView) findViewById(R.id.btnFindGame);
final ImageView profile = (ImageView) findViewById(R.id.btnProfile);
final ImageView instructions = (ImageView) findViewById(R.id.btnInstructions);
final ImageView options = (ImageView) findViewById(R.id.btnOptions);
findGame.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, DrawActivity.class);
startActivity(intent);
}
});
profile.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, WaitingActivity.class);
startActivity(intent);
}
});
instructions.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, InstructionsActivity.class);
startActivity(intent);
}
});
options.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, OptionsActivity.class);
startActivity(intent);
}
});
}
//On app close, music stops playing.
@Override
protected void onDestroy() {
if (this.isFinishing()){
super.onDestroy();
stopService(i);
//finish();
}
}
}
答案 0 :(得分：2)
当您创建主屏幕时，您也将再次启动该服务。在服务的“onStartCommand”中，您正在启动媒体播放器。这意味着每次进入主页时，媒体播放器都会重新开始播放。
我建议不要将mp.start();放在'onStartCommand'中，而是放在自己的函数中。然后在调用startService(i);后，您可以使用bindService()绑定到服务，然后在您拥有的服务句柄上调用play（）等函数。
当然，如果您暂停播放歌曲而不是停止播放，则需要保存歌曲的位置，然后在重新启动服务时使用seekTo()将歌曲移动到正确的位置。
答案 1 :(得分：0)
我认为你必须在你的家庭班上使用create method
检查启动服务 check if(your service is running)
{
if(mp is playing)
{
//do nothing
}
}
else
{
startservice();
}