How to solve MediaPlayer IllegalStateException iss

I know there is a lot of questions about this subject, but none of them helped me. I tried ALL but nothing, still getting IllegalStateException in my logcat and app crashes.

Here is my MainActivity.java:

package com.orar.cngcnasaud;

import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

    private ListView mDrawerList;
    private DrawerLayout mDrawer;
    private CustomActionBarDrawerToggle mDrawerToggle;
    private String[] menuItems;


    private static final String TAG = "AudioDemo";
    private static final String isPlaying = "Media is Playing"; 
    private static final String notPlaying = "Media has stopped Playing"; 

    MediaPlayer player;
    Button playerButton;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_drawer);

        player = MediaPlayer.create(this, R.raw.gc);
        player.setLooping(false); // Set looping

        // Get the button from the view
        playerButton = (Button) this.findViewById(R.id.buttonmp);
        playerButton.setText(R.string.stop_label);
        playerButton.setOnClickListener((OnClickListener) this);

        // Begin playing selected media
        demoPlay();

        // Release media instance to system
        player.release();


        // enable ActionBar app icon to behave as action to toggle nav drawer
        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);

        // set a custom shadow that overlays the main content when the drawer
        // opens
        mDrawer.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);

        _initMenu();
        mDrawerToggle = new CustomActionBarDrawerToggle(this, mDrawer);
        mDrawer.setDrawerListener(mDrawerToggle);
    }

        public void onClick(View v) {
            Log.d(TAG, "onClick: " + v);
            if (v.getId() == R.id.buttonmp) {
                playPause();
            }

    }




    private void demoPause() {
        // TODO Auto-generated method stub
        player.pause();
        playerButton.setText(R.string.play_label);
        Toast.makeText(this, notPlaying, Toast.LENGTH_LONG).show();
        Log.d(TAG, notPlaying);
}

    private void playPause() {
        // TODO Auto-generated method stub
        if(player.isPlaying()) {
          demoPause();
        } else {
          demoPlay();
        }   
    }

    private void demoPlay() {
        // TODO Auto-generated method stub
        player.start();
        playerButton.setText(R.string.stop_label);
        Toast.makeText(this, isPlaying, Toast.LENGTH_LONG).show();
        Log.d(TAG, isPlaying);
}

This is not the whole activity, my activity has a sliding menu too, but this is the code for my MediaPlayer .. Thanks a lot !

L.E:

LOGCAT:

02-24 19:09:24.011: E/AndroidRuntime(1323): FATAL EXCEPTION: main
02-24 19:09:24.011: E/AndroidRuntime(1323): java.lang.IllegalStateException
02-24 19:09:24.011: E/AndroidRuntime(1323):     at android.media.MediaPlayer.isPlaying(Native Method)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at com.orar.cngcnasaud.MainActivity.playPause(MainActivity.java:90)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at com.orar.cngcnasaud.MainActivity.onClick(MainActivity.java:72)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at android.view.View.performClick(View.java:4204)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at android.view.View$PerformClick.run(View.java:17355)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at android.os.Handler.handleCallback(Handler.java:725)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at android.os.Handler.dispatchMessage(Handler.java:92)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at android.os.Looper.loop(Looper.java:137)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at android.app.ActivityThread.main(ActivityThread.java:5041)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at java.lang.reflect.Method.invokeNative(Native Method)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at java.lang.reflect.Method.invoke(Method.java:511)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
02-24 19:09:24.011: E/AndroidRuntime(1323):     at dalvik.system.NativeStart.main(Native Method)

回答1:

Here:

 if(player.isPlaying()) {

You seem to be calling ìsPlaying() method while the player has not yet been initialized. In that case this method throws this IllegalStateException.

I think reason is that in your onCreate you actually release (!) the MediaPlayer, see:

   // Release media instance to system
    player.release();

You should better use the Activity life cycle methods to manage releasing your MediaPlayer:

@Override
public void onPause() {
    player.stop();
    player.release();
    super.onPause();
}

@Override
public void onResume() {
    player = MediaPlayer.create(this, R.raw.gc);
    player.setLooping(false);
    player.start(); 
    super.onResume();
}

回答2:

It sounds like an initialization problem. Although I have not done a ton of research, here is a possible duplicate:

java.lang.IllegalStateException in MediaPlayer.isplaying() method

Here is another duplicate, also pointing to initialization:

android java.lang.IllegalStateException MediaPlayer.isPlaying

And here is the dev docs on MediaPlayer, stating prior to calling isPlaying() you'll need to initialize the player:

http://developer.android.com/reference/android/media/MediaPlayer.html#isPlaying()