Develop Reference

Change background music volume from activity to service

I'm new to android, and working on a project where I have to implement background music in our app. I've already implemented background music using service, the problem is: I don't know how to change the volume of the music dynamically using a seekbar from an activity.
My service looks like this:
package hu.szoftverprojekt.holdemfree.controller;
import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.IBinder;
import androidx.annotation.Nullable;
import hu.szoftverprojekt.holdemfree.R;
public class PlaySound extends Service {
MediaPlayer player;
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
player=MediaPlayer.create(this, R.raw.ss);
player.setLooping(true);
player.start();
player.setVolume(SettingsScreen.volume, SettingsScreen.volume);
return START_STICKY;
}
#Override
public void onDestroy() {
super.onDestroy();
player.stop();
}
}

Well once you have the SeekBar and the OnSeekBarChangeListener being called as you change the SeekBar, the next major thing is communicating this from your activity to your service this change.
Have a look at the android docs Creating a bound service for the offical way to communicate between an Activity and Service using no 3rd party libraries.
HOWEVER
You could also use a 3rd party library like EventBus (which I'd recommend as it's much easier to use and implement in my opinion).
Here is an example using EventBus:
build.gradle:
dependencies {
implementation 'org.greenrobot:eventbus:3.2.0'
}
MediaVolumeEvent.java:
public class MediaVolumeEvent {
private int volume;
public MediaVolumeEvent(int volume) {
this.volume = volume;
}
public int getVolume() {
return volume;
}
}
PlaySound.java:
public class PlaySound extends Service {
#Override
public void onCreate() {
super.onCreate();
EventBus.getDefault().register(this);
}
#Override
public void onDestroy() {
EventBus.getDefault().unregister(this);
player.stop();
super.onDestroy();
}
#Subscribe(threadMode = ThreadMode.MAIN)
public void onEvent(MediaVolumeEvent event){
player.setVolume(event.getVolume(), event.getVolume());
}
}
In your activity inside the OnSeekBarChangeListener:
SeekBar seekBar= (SeekBar) findViewById(R.id.seekBar);
seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
#Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
EventBus.getDefault().post(new MediaVolumeEvent(progress));
}
});

Multithreading with MVP & violation in Android

I want to convert my project according to MVP structure, & I had done it but it violate the MVP design, as it holds the activity instance in the presenter layer.
So, I just wanted to know how can I convert this project into pure MVP. Here Validation class is recursive and validate many fields & for here it is just for signup, and I had put the Validate method into separate thread.
This is my MVP interface
import android.app.Activity;
public class IMVP_Login {
/**
* View mandatory methods. Available to Presenter
* Presenter -> View
*/
public interface RequiredViewOps {
void showToast(String msg);
}
/**
* Operations offered from Presenter to View
* View -> Presenter
*/
public interface PresenterOps{
void submit(Activity activity);
}
}
This is my presenter with thread and containing the activity instance, which is against the design pattern of MVP, the code is as follows
import android.app.Activity;
import java.lang.ref.WeakReference;
import cp.utility.CustomException;
import cp.utility.Validation;
public class PresenterLogin implements Runnable,IMVP_Login.PresenterOps
{
private WeakReference<IMVP_Login.RequiredViewOps> mView;
// this is against the architectural law of MVP
private WeakReference<Activity> activity;
public PresenterLogin(IMVP_Login.RequiredViewOps mView) {
this.mView = new WeakReference<>(mView);
}
#Override
public void run() {
try
{
Validation.validate(activity.get());
}catch (CustomException e)
{
mView.get().showToast(e.getMessage());
}
}
//how should i do this with MVP PATTERN,as it is holding the activity instance
#Override
public void submit(Activity activity) {
this.activity=new WeakReference<>(activity);
Thread validationThread = new Thread(this,"Validation");
validationThread.start();
}
}
This is my activity,
public class Login extends AppCompatActivity implements View.OnClickListener,IMVP_Login.RequiredViewOps
{
private TextInputEditText edPhone,edCountrycode,edPassword;
private IMVP_Login.PresenterOps presenterLogin;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_signin);
initialize();
}
private void initialize()
{
presenterLogin= new PresenterLogin(this);
Button btSignIn=GeneralFunction.findViewByIdAndCast(this,R.id.btnSignIn);
btSignIn.setOnClickListener(this);
edCountrycode = GeneralFunction.findViewByIdAndCast(this, R.id.etCode);
edPhone = GeneralFunction.findViewByIdAndCast(this, R.id.etPhone);
edPassword = GeneralFunction.findViewByIdAndCast(this, R.id.etPassword);
edPassword.setTypeface(Typekit.getInstance().get(getString(R.string.str_regular)));
edPassword.setTransformationMethod(new PasswordTransformationMethod());
}
#Override
public void onClick(View view) {
switch (view.getId())
{
case R.id.btnSignIn:
presenterLogin.submit(this);
break;
}
}
#Override
public void showToast(String msg) {
//show toast
}
}
This is the validation class depending on tag of editext,
public class Validation {
public static boolean validateFields(final ViewGroup parentView) throws CustomException
{
for (int i = 0; i < parentView.getChildCount(); i++)
{
if (parentView.getChildAt(i) instanceof ViewGroup) {
if ((parentView.getChildAt(i)).getVisibility() == View.VISIBLE)
validateFields((ViewGroup) parentView.getChildAt(i));
}
else if((parentView.getChildAt(i) instanceof TextView) && ((parentView.getChildAt(i)).getVisibility() == View.VISIBLE))
{
TextView editText = (TextView) parentView.getChildAt(i);
if(null!=editText.getTag())
{
String type = editText.getTag().toString().toLowerCase();
String text=GeneralFunction.getTextFromView(editText);
//validation depending on tag
}
}
}
return true;
}
public static boolean validate(Activity activity) {
final ViewGroup viewGroup = (ViewGroup) activity.findViewById(android.R.id.content);
return validateFields(viewGroup);
}
}

Let me start by saying that there are many different ways of doing MVP, each of them valid in their own right. The important things to keep in mind are:
The View should not know about the model, it doesn't care at all where its data is coming from.
The Presenter should not know about Android. You should be able to run your Presenter class entirely on the JVM.
Your Activity/Fragment/ViewGroup should implement the View interface which is how the Presenter communicates with them.
Why do we do this?
Separation of concerns.
You can change the network library you use in your Model and the View/Presenter should just work still. You could switch your View from a horizontal ViewPager to a vertical RecyclerView and the Presenter/Model equally wouldn't care.
Testing.
We can mock our Presenter and unit test the View or Model. Mock the View & Model and unit test the Presenter.
As long as the implementation of MVP that you are using allows the above then in my mind it is valid.
Onto your specific problem. I would set it up something like this:
View:
public interface LoginView {
Map<String,String> getLoginFields();
}
Activity:
public class LoginActivity extends AppCompatActivity implements LoginView {
private EditText emailView;
private EditText phoneView;
private EditText passwordView;
private Button loginView;
private LoginPresenter presenter;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
presenter = new LoginPresenter();
presenter.bindView(this);
emailView = findViewById(R.id.login_email);
phoneView = findViewById(R.id.login_phone);
passwordView = findViewById(R.id.login_password);
loginView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
presenter.login();
}
});
}
#Override
protected void onDestroy() {
presenter.unbindView();
super.onDestroy();
}
#Override
public Map<String, String> getLoginFields() {
Map<String, String> fields = new HashMap<>();
fields.put(emailView.getTag().toString(), emailView.getText().toString());
fields.put(phoneView.getTag().toString(), phoneView.getText().toString());
fields.put(passwordView.getTag().toString(), passwordView.getText().toString());
return fields;
}
}
You may wish to do something fancy with the getLoginFields method and loop through your container. Even if you had 100 fields though it shouldn't require offloading onto another thread. I'd be a very upset user if I had to fill out 100 fields...
Presenter:
public class LoginPresenter {
private LoginView view;
private LoginValidator validator;
public void bindView(LoginView view) {
this.view = view;
}
public void unbindView() {
view = null;
}
public void login() {
validator = new LoginValidator();
Map<String, String> fields = view.getLoginFields();
boolean isValid = validator.validate(fields);
}
}
Validator:
public class LoginValidator {
public boolean validate(Map<String, String> fields) {
//validation depending on tag
return true;
}
}
Threading
If the need does arise to process something on another thread in the Activity then you have several approaches you could take:
Pass a listener to the getLoginFields() method which gets called when the work is done.
Expose another method in the Presenter, something like onLoginFieldsProcessed which would get called once the work is done.
Have getLoginFields() return Observable (RxJava) or Future.
I would personally probably use RxJava, especially if I was already using it in the app.

The main reason why there is separate presenter class added in this MVP framework ( especially in android ) is to remove the OutOfMemory or if by chance the activity fails the presenter calls is not affected i.e why there is MVP approach followed instead of MV framework.
Consider the below example that is from below link :-
public class MainActivity extends Activity {
public static final String DEFAULT_NAME = "Chuck Norris";
private ArrayAdapter<ServerAPI.Item> adapter;
private Subscription subscription;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listView = (ListView)findViewById(R.id.listView);
listView.setAdapter(adapter = new ArrayAdapter<>(this, R.layout.item));
requestItems(DEFAULT_NAME);
}
#Override
protected void onDestroy() {
super.onDestroy();
unsubscribe();
}
public void requestItems(String name) {
unsubscribe();
subscription = App.getServerAPI()
.getItems(name.split("\\s+")[0], name.split("\\s+")[1])
.delay(1, TimeUnit.SECONDS)
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<ServerAPI.Response>() {
#Override
public void call(ServerAPI.Response response) {
onItemsNext(response.items);
}
}, new Action1<Throwable>() {
#Override
public void call(Throwable error) {
onItemsError(error);
}
});
}
public void onItemsNext(ServerAPI.Item[] items) {
adapter.clear();
adapter.addAll(items);
}
public void onItemsError(Throwable throwable) {
Toast.makeText(this, throwable.getMessage(), Toast.LENGTH_LONG).show();
}
private void unsubscribe() {
if (subscription != null) {
subscription.unsubscribe();
subscription = null;
}
}
}
In the above example the activity failure causes the presenter layer to stop working .Similarly ,if there is any object associated with this activity class ( View ) will be affected .
Referencing by static will make the activity die out while there is a crash but the presenter class will not be affected.( Please refer to below code for MVP ).
public class MainPresenter {
public static final String DEFAULT_NAME = "Chuck Norris";
private ServerAPI.Item[] items;
private Throwable error;
private MainActivity view;
public MainPresenter() {
App.getServerAPI()
.getItems(DEFAULT_NAME.split("\\s+")[0], DEFAULT_NAME.split("\\s+")[1])
.delay(1, TimeUnit.SECONDS)
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<ServerAPI.Response>() {
#Override
public void call(ServerAPI.Response response) {
items = response.items;
publish();
}
}, new Action1<Throwable>() {
#Override
public void call(Throwable throwable) {
error = throwable;
publish();
}
});
}
public void onTakeView(MainActivity view) {
this.view = view;
publish();
}
private void publish() {
if (view != null) {
if (items != null)
view.onItemsNext(items);
else if (error != null)
view.onItemsError(error);
}
}
}
public class MainActivity extends Activity {
private ArrayAdapter<ServerAPI.Item> adapter;
private static MainPresenter presenter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listView = (ListView)findViewById(R.id.listView);
listView.setAdapter(adapter = new ArrayAdapter<>(this, R.layout.item));
if (presenter == null)
presenter = new MainPresenter();
presenter.onTakeView(this);
}
#Override
protected void onDestroy() {
super.onDestroy();
presenter.onTakeView(null);
if (!isChangingConfigurations())
presenter = null;
}
public void onItemsNext(ServerAPI.Item[] items) {
adapter.clear();
adapter.addAll(items);
}
public void onItemsError(Throwable throwable) {
Toast.makeText(this, throwable.getMessage(), Toast.LENGTH_LONG).show();
}
}
MainActivity creates MainPresenter and keeps it outside of reach of onCreate/onDestroy cycle. MainActivity uses a static variable to reference MainPresenter, so every time a process restarts due to out-of-memory event, MainActivity should check if the presenter is still here and create it if needed.( As stated in the doc ).
Hope this helps :)

Android Media Player App services

I am developing a media player app that has a bound service to an activity.It works fine when i press the home button or the app switcher and then come back to the app from the recent app, but as i press the back button the activity also ends the Music Service. Please guide me the exact steps that can solve these minor issues, so that i can give media controls to the app.My App has 2 main classes
MyActivity
AudioService
My code is given below.
AudioService.java
public class AudioService extends Service implements
MediaPlayer.OnPreparedListener, MediaPlayer.OnErrorListener,
MediaPlayer.OnCompletionListener{
// -----------------------------------------Attributes--------------------------------------------------------
private ArrayList<File> songs;
private ArrayList<File> audio;
private MediaPlayer player;
private int songPosn;
private String name="";
private final IBinder musicBind = new AudioBinder();
private Uri trackUri;
private int NOTIFY_ID=1;
// -----------------------------------------------------------------------------------------------------------
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
public void onCreate(){
//create the service
//create the service
super.onCreate();
//initialize position
songPosn=0;
//create player
player = new MediaPlayer();
initMusicPlayer();
}
// to initialize the media class
public void initMusicPlayer(){
//set player properties
player.setWakeMode(getApplicationContext(),
PowerManager.PARTIAL_WAKE_LOCK);
player.setAudioStreamType(AudioManager.STREAM_MUSIC);
player.setOnPreparedListener(this);
player.setOnCompletionListener(this);
player.setOnErrorListener(this);
}
public void setList(ArrayList<File> theSongs){
songs=theSongs;
}
public void setSong(int songIndex){
songPosn=songIndex;
}
public class AudioBinder extends Binder {
AudioService getService() {
return AudioService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return musicBind;
}
#Override
public boolean onUnbind(Intent intent){
player.stop();
player.release();
return false;
}
#Override
public void onCompletion(MediaPlayer mp) {
}
#Override
public boolean onError(MediaPlayer mp, int what, int extra) {
mp.reset();
return false;
}
#Override
public void onPrepared(MediaPlayer mp) {
//start playback
mp.start();
showNotification();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId){
songPosn = intent.getIntExtra("pos",0);
audio=(ArrayList)intent.getParcelableArrayListExtra("songlist");
name = intent.getStringExtra("name");
Log.e("Service","name"+audio.get(0));
Log.e("Service","position "+songPosn);
return START_STICKY;
}
public void playSong(){
//play a song
player.reset();
Log.e("TRACH the URI",""+trackUri);
trackUri =Uri.parse(audio.get(songPosn).toString());
try{
player.setDataSource(getApplicationContext(), trackUri);
}
catch(Exception e){
Log.e("MUSIC SERVICE", "Error setting data source", e);
}
player.prepareAsync();
}
private void showNotification(){
Intent notIntent = new Intent(this, MyActivity.class);
notIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
PendingIntent pendInt = PendingIntent.getActivity(this, 0,
notIntent, PendingIntent.FLAG_UPDATE_CURRENT);
Notification.Builder builder = new Notification.Builder(this);
builder.setContentIntent(pendInt)
.setTicker(name)
.setOngoing(true)
.setContentTitle("Playing")
.setContentText(name);
Notification not = builder.build();
startForeground(NOTIFY_ID, not);
}
#Override
public void onDestroy()
{
stopForeground(true);
}
}
MyActivity.java
public class MyActivity extends Activity {
// ***************************** Attributes Start ******************************************************
private ArrayList<File> myfiles= new ArrayList<File>();
private ListView listView;
private ArrayAdapter<String> adapter ;
private String name="";
private int position;
private AudioService musicSrv;
private Intent playIntent;
private boolean musicBound=false;
// ***************************** Attributes End ******************************************************
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
String toneslist[] ={"Airtel"
,"sherlock_theme"};
listView = (ListView) findViewById(R.id.listView);
adapter = new ArrayAdapter<String>(getApplication(),R.layout.list_item,R.id.list_textview,toneslist);
listView.setAdapter(adapter);
getMp3();
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int pos, long id) {
name =adapter.getItem(pos);
position =pos;
Log.e("MAINACTIVITY (clickListener) pos =",""+position+" name = "+name);
musicSrv.setSong(position);
musicSrv.playSong();
}
});
}
#Override
protected void onStart() {
super.onStart();
if(playIntent==null){
Log.e("MAINACTIVITY pos =",""+position+" name = "+name);
playIntent = new Intent(this, AudioService.class).putExtra("pos",position).putExtra("songlist", myfiles).putExtra("name", name);
bindService(playIntent, audioConnection, Context.BIND_AUTO_CREATE);
startService(playIntent);
}
}
private ServiceConnection audioConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName name, IBinder service) {
AudioService.AudioBinder binder = (AudioService.AudioBinder)service;
musicSrv = binder.getService();
musicSrv.setList(myfiles);
musicBound = true;
}
#Override
public void onServiceDisconnected(ComponentName name) {
musicBound = false;
}
};
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.my, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private void getMp3(){
String s=(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC)).toString();
// s="content://media/external/audio/media";
GetFiles(s);
}
private void GetFiles(String path) {
File file = new File(path);
File[] allfiles = file.listFiles();
if (allfiles.length == 0) {
} else {
for (int i = 0; i < allfiles.length; i++)
{
Log.e("FFFFFFFFF", allfiles[i].getName().toString());
myfiles.add(allfiles[i]);
}
}
}
#Override
protected void onPause() {
super.onPause();
}
#Override
protected void onDestroy() {
stopService(playIntent);
musicSrv=null;
super.onDestroy();
}
}

Try with this in your Activity:
#Override
public void onDestroy(){
if (!isChangingConfigurations()) stopService(new Intent (this, YourService.class));
super.onDestroy();
}
#Override
public void onBackPressed(){
if (mediaIsPlaying) moveTaskToBack(true);
else super.onBackPressed();
}

App crashing when saving to shared preferences

I am trying to save to shared preferences. I want to be able to load from shared preferences but when I save and or load at the moment my app crashes.
I also want to be able to have my handler/runnable resume when my app starts up. How can I do this?
Here is my code:
public class MainActivity extends ActionBarActivity {
public void save(){
Editor editor = pref.edit();
editor.putInt("countertest", counter);
editor.commit();
}//end of save
public void read(){
counter = pref.getInt("countertest", counter);
}//end of read
Handler testHandler = new Handler();
int counter;
TextView testView;
Button testButton;
Runnable Runnable0;
SharedPreferences pref;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
testView = (TextView) findViewById(R.id.testView);
testButton = (Button) this.findViewById(R.id.testButton);
// read();
testView.setText(Integer.toString(counter));
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
protected void onResume() {
//read();
final Runnable Runnable0 = new Runnable() {
#Override
public void run() {
counter += 1;
testView.setText(Integer.toString(counter));
testHandler.postDelayed(this, 1000);
// save();
}// end of if
};
/* button click */
testButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
/* Start runnable */
testButton.setEnabled(false);
counter -= 5;
//save();
testView.setText(Integer.toString(counter));
testHandler.post(Runnable0);
}// end of onClick
});// end of blingButton onClickListener
super.onResume();
}//end of onResume
#Override
protected void onPause() {
//save();
testHandler.removeCallbacks(Runnable0);
super.onPause();
}//end of onPause
}

You haven't initialize your pref object. You have just declared it. So you need to do it on onCreate() by
pref = getSharedPreferences("MySP", 0);
OR
pref = PreferenceManager.getDefaultSharedPreferences(this);

How to implement completion listener in media player android image view

I am working on project that plays background music when user slides through the images. And musci stops when users reaches the last image. It also starts playing when user backslides. However, my song is short and I want to implement completion listener so that when first music ends the second music starts from the raw folder. My main problem is that I don't know how to implement it in my mainactivity.java. I have also read android official guidelines but it didn't helped. Please provide some help along with explanation...
My codes are the following
Mainactivity.java
import android.app.Activity;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ShareActionProvider;
public class MainActivity extends Activity {
MediaPlayer oursong;
ViewPager viewPager;
ImageAdapter adapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
oursong = MediaPlayer.create(MainActivity.this, R.raw.a);
oursong.seekTo(0);
oursong.start();
viewPager = (ViewPager) findViewById(R.id.view_pager);
adapter = new ImageAdapter(this);
viewPager.setAdapter(adapter);
viewPager.setOnPageChangeListener(MyViewPagerListener);
}
private ShareActionProvider mShareActionProvider;
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate menu resource file.
getMenuInflater().inflate(R.menu.activity_main, menu);
// Locate MenuItem with ShareActionProvider
MenuItem item = menu.findItem(R.id.menu_item_share);
// Fetch and store ShareActionProvider
mShareActionProvider = (ShareActionProvider) item.getActionProvider();
// Return true to display menu
return true;
}
// Call to update the share intent
private void setShareIntent(Intent shareIntent) {
if (mShareActionProvider != null) {
mShareActionProvider.setShareIntent(shareIntent);
}
}
private int pos = 0;
#Override
protected void onPause() {
super.onPause();
if(oursong != null){
pos = oursong.getCurrentPosition();
oursong.release();
oursong = null;
}
}
#Override
protected void onResume(){
super.onResume();
oursong = MediaPlayer.create(MainActivity.this, R.raw.a);
oursong.seekTo(pos); // You will probably want to save an int to restore here
oursong.start();
}
private final OnPageChangeListener MyViewPagerListener = new OnPageChangeListener() {
#Override
public void onPageSelected(int pos) {
if (pos == adapter.getCount() - 1){
// adding null checks for safety
if(oursong != null){
oursong.pause();
}
} else if (!oursong.isPlaying()){
// adding null check for safety
if(oursong != null){
oursong.start();
}
}
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub
}
#Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
}
};
}

You have to set on completion listener on mediaplayer instance to determine the song is played
mP.setOnCompletionListener(new OnCompletionListener() {
#Override
public void onCompletion(MediaPlayer mp) {
try {
mp.start();
mp.setLooping(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});

The basic idea is that you need to change the states of the player in the correct order. OnCompletion you need to reset, change music, prepare async.
OnPrepared you need to start playing.
To do that change this code:
oursong = MediaPlayer.create(MainActivity.this, R.raw.a);
oursong.seekTo(0);
oursong.start();
into
MyTracksCustomClass tracks = new MyTracksCustomClass();
MediaPlayer oursong = MediaPlayer.create(MainActivity.this, R.raw.a);
oursong.setLooping(false);
oursong.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
#Override
public void onCompletion(MediaPlayer mediaPlayer) {
mediaPlayer.reset();
try {
mediaPlayer.setDataSource(MainActivity.this, tracks.getNextTrack);
} catch (IOException e) {
e.printStackTrace();
}
try {
mediaPlayer.prepareAsync();
} catch (IllegalStateException e) {
e.printStackTrace();
}
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
#Override
public void onPrepared(MediaPlayer mediaPlayer) {
mediaPlayer.start();
}
});
}
}
});
You need another class to manage getting the next track "MyTracksCustomClass" in which you should implement sth like:
class MyTracksCustomClass {
int trackIndex;
HashMap<String, Integer> trackResourceIds;
MyTracksCustomClass()
{
trackIndex = 1;
// in case you only have two tracks
trackResourceIds = new HashMap<String, Integer>();
trackResourceIds.put("1",R.raw.a);
trackResourceIds.put("2",R.raw.b);
}
public int getNextTrack() {
// in case you only have two tracks
trackIndex = (trackIndex > 3 )? 1 : trackIndex;
return trackResourceIds.get(trackIndex++ +"");
}
}