我正在创建一个应用程序，当用户登录时，他可以根据需要设置设置。我有首选项xml（名为settings.xml）。有两个选项1）背景音乐（通过开关首选项打开或关闭）2）选择歌曲（列表首选项）.Below是我的主要活动代码： -
public class SettingsActivity extends PreferenceActivity {
MediaPlayer mp;
SharedPreferences pref;
Preference p;
MyProfile myProfile;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
pref = PreferenceManager.getDefaultSharedPreferences(this);
getFragmentManager().beginTransaction().replace(android.R.id.content,
new PrefsFragment()).commit();
PreferenceManager.setDefaultValues(SettingsActivity.this, R.xml.settings, false);
}
@SuppressLint("ValidFragment")
public class PrefsFragment extends PreferenceFragment{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
}
@Override
public void onResume(){
super.onResume();
// Set up a listener whenever a key changes
getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(listener);
for (int i = 0; i < getPreferenceScreen().getPreferenceCount(); ++i) {
Preference preference = getPreferenceScreen().getPreference(i);
if (preference instanceof PreferenceGroup) {
PreferenceGroup preferenceGroup = (PreferenceGroup) preference;
for (int j = 0; j < preferenceGroup.getPreferenceCount(); ++j) {
updatePrefSummary(preferenceGroup.getPreference(j));
}
} else {
updatePrefSummary(preference);
}
}
}
@Override
public void onPause() {
super.onPause();
// Unregister the listener whenever a key changes
stopPlay();
getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(listener);
}
public void onDestroy() {
super.onDestroy();
// Unregister the listener whenever a key changes
getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(listener);
};
OnSharedPreferenceChangeListener listener = new OnSharedPreferenceChangeListener() {
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
String key) {
// TODO Auto-generated method stub
updatePrefSummary(findPreference(key));
String ringTone = sharedPreferences.getString("prefRingtone", "0");
int num = Integer.parseInt(ringTone);
if(num == 0){
mp= MediaPlayer.create(getApplicationContext(), R.raw.airtel);
}
else if(num == 1){
mp= MediaPlayer.create(getApplicationContext(), R.raw.dance);
}
else if(num == 2){
mp= MediaPlayer.create(getApplicationContext(), R.raw.dhoom);
}
else{
mp= MediaPlayer.create(getApplicationContext(), R.raw.guitar);
}
mp.setLooping(false);
if(sharedPreferences.getBoolean("prefMusic", false)){
mp.start();
}
else {
mp.stop();
// mp.release();
}
}
};
private void updatePrefSummary(Preference p){
if(p instanceof ListPreference){
ListPreference listPref = (ListPreference) p;
p.setSummary(listPref.getEntry());
}
else{
SwitchPreference swPref = (SwitchPreference)p;
if(pref.getBoolean("prefMusic", true)){
swPref.setSwitchTextOn("ON");
p.setSummary(swPref.getSwitchTextOn());
}
else{
swPref.setSwitchTextOff("OFF");
p.setSummary(swPref.getSwitchTextOff());
}
}
}
public void stopPlay(){
/* if(myProfile.isFinishing()){
mp.stop();
//mp.release();
}*/
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())){
mp.stop();
//mp.release();
}
else{
}
}
super.onPause();
}
}
}
我的问题是当我分别打开和关闭它们时，背景音乐无法正常工作。有些时间没有播放，当它开始播放时，它不会停止（我是否选择关闭）。请帮助我摆脱这个。任何帮助都将受到高度赞赏。
感谢。
答案 0 :(得分：1)
private class BackgroundPlayer {
private Context ctx;
private MediaPlayer mediaPlayer;
public BackgroundPlayer(Context ctx, int res) {
this.ctx = ctx;
mediaPlayer = MediaPlayer.create(this.ctx, res);
mediaPlayer.setLooping(true);
}
public void startBackgroundMusic() {
if(mediaPlayer!=null&&!mediaPlayer.isPlaying())
mediaPlayer.start();
}
public void stopBackgroundMusic() {
if(mediaPlayer!=null)
mediaPlayer.pause();
}
public void kill() {
if(mediaPlayer!=null) {
mediaPlayer.stop();
mediaPlayer.release();
mediaPlayer = null;
ctx = null;
}
}
}
backgroundPlayer = new BackgroundPlayer(this, R.raw.filename);
在onPause
backgroundPlayer.stopBackgroundMusic();
if(condition == true) backgroundPlayer.startBackgroundMusic();
backgroundPlayer.kill();
答案 1 :(得分：0)
好的，我得到了正常工作的代码： -
public class SettingsActivity extends PreferenceActivity {
MediaPlayer mp;
SharedPreferences pref;
Preference p;
MyProfile myProfile;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
pref = PreferenceManager.getDefaultSharedPreferences(this);
getFragmentManager().beginTransaction().replace(android.R.id.content,
new PrefsFragment()).commit();
PreferenceManager.setDefaultValues(SettingsActivity.this, R.xml.settings, false);
}
@SuppressLint("ValidFragment")
public class PrefsFragment extends PreferenceFragment{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
}
@Override
public void onResume(){
super.onResume();
// Set up a listener whenever a key changes
getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(listener);
for (int i = 0; i < getPreferenceScreen().getPreferenceCount(); ++i) {
Preference preference = getPreferenceScreen().getPreference(i);
if (preference instanceof PreferenceGroup) {
PreferenceGroup preferenceGroup = (PreferenceGroup) preference;
for (int j = 0; j < preferenceGroup.getPreferenceCount(); ++j) {
updatePrefSummary(preferenceGroup.getPreference(j));
}
} else {
updatePrefSummary(preference);
}
}
}
@Override
public void onPause() {
super.onPause();
// Unregister the listener whenever a key changes
// stopPlay();
// getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(listener);
}
public void onDestroy() {
super.onDestroy();
// Unregister the listener whenever a key changes
// stopPlay();
getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(listener);
};
OnSharedPreferenceChangeListener listener = new OnSharedPreferenceChangeListener() {
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
String key) {
// TODO Auto-generated method stub
updatePrefSummary(findPreference(key));
String ringTone = sharedPreferences.getString("prefRingtone", "0");
int num = Integer.parseInt(ringTone);
if(mp!=null){
if(mp.isPlaying()){
mp.stop();
}
if(num == 0){
mp= MediaPlayer.create(getApplicationContext(), R.raw.airtel);
}
else if(num == 1){
mp= MediaPlayer.create(getApplicationContext(), R.raw.dance);
}
else if(num == 2){
mp= MediaPlayer.create(getApplicationContext(), R.raw.dhoom);
}
else{
mp= MediaPlayer.create(getApplicationContext(), R.raw.guitar);
}
}
else{
if(num == 0){
mp= MediaPlayer.create(getApplicationContext(), R.raw.airtel);
}
else if(num == 1){
mp= MediaPlayer.create(getApplicationContext(), R.raw.dance);
}
else if(num == 2){
mp= MediaPlayer.create(getApplicationContext(), R.raw.dhoom);
}
else{
mp= MediaPlayer.create(getApplicationContext(), R.raw.guitar);
}
}
// mp= MediaPlayer.create(getApplicationContext(), R.raw.airtel);
mp.setLooping(true);
Boolean onORoff = sharedPreferences.getBoolean("prefMusic", false);
if(onORoff){
mp.start();
}
else {
mp.pause();
// mp.release();
}
}
};
private void updatePrefSummary(Preference p){
if(p instanceof ListPreference){
ListPreference listPref = (ListPreference) p;
p.setSummary(listPref.getEntry());
}
else{
SwitchPreference swPref = (SwitchPreference)p;
if(pref.getBoolean("prefMusic", true)){
swPref.setSwitchTextOn("ON");
p.setSummary(swPref.getSwitchTextOn());
}
else{
swPref.setSwitchTextOff("OFF");
p.setSummary(swPref.getSwitchTextOff());
}
}
}
}
}