I create a project, and this is MainActivity class
package com.example.myproject;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.*;
public class MainActivity extends Activity {
Button btnmulai, btnpengaturan, btnexit,btninfo;
MediaPlayer player;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnpengaturan=(Button)findViewById(R.id.btnPengaturan);
btnmulai=(Button)findViewById(R.id.btnMulai);
btnexit=(Button)findViewById(R.id.btnExit);
btninfo=(Button)findViewById(R.id.btnInfo);
btnpengaturan.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View arg0)
{
// TODO Auto-generated method stub
Intent intent = new Intent(MainActivity.this, Pengaturan.class);
playSound(1);
startActivity(intent);
}
});
btnmulai.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View arg0)
{
// TODO Auto-generated method stub
Intent intent = new Intent(MainActivity.this, Prolog.class);
playSound(1);
startActivity(intent);
}
});
btninfo.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View arg0)
{
// TODO Auto-generated method stub
playSound(1);
AlertDialog.Builder alertinfo = new AlertDialog.Builder(MainActivity.this);
alertinfo.setMessage("Info saja");
alertinfo.setTitle("INFO");
alertinfo.setPositiveButton("OK", null);
alertinfo.setCancelable(true);
alertinfo.create().show();
}
});
btnexit.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which)
{
switch (which)
{
case DialogInterface.BUTTON_POSITIVE:
// TODO Auto-generated method stub
finish();
System.exit(0);
break;
case DialogInterface.BUTTON_NEGATIVE:
//No button clicked
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setMessage("Anda yakin ingin keluar?").setPositiveButton("Yes", dialogClickListener).setNegativeButton("No", dialogClickListener).show();
}
});
}
public void playSound(int arg)
{
try
{
if (player.isPlaying())
{
player.stop();
player.release();
}
}
catch(Exception e)
{
}
if (arg == 1)
{
player = MediaPlayer.create(this, R.raw.atur);
}
player.setLooping(false);
player.start();
}
@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;
}
}
When i try to compile on Bluestacks or Galaxy S4, it is working, but when i tried to compile on a Tablet, and i press the btnmulai or btninfo, it said that "Unfortunately, myproject has stopped".. This is the Logcat error:
FATAL EXCEPTION: main
java.lang.NullPointerException
at com.example.myproject.MainActivity.playSound(MainActivity.java:135)
at com.example.myproject.MainActivity.$3.onClick(MainActivity.java:67)
at android.view.View.performClick(View.java:4206)
at android.view.View$PerformClick.run(View.java:17357)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.invokeNative(Native Method)
at java.lang.reflect.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
I don't know why, any answer?
Try this..
I think you haven't initilize the player so that null pointer coming
You nee to check player is null or not with this
if(player != null){ }
Elample is below
EDIT: