[Android Studio] tsueseres:
hello, im having trouble moving a chathead with a button, no matter how much i try it always crashes my app

here is the main activity

im using MoveHead but i dant make it to work

package example.com.chatheads;

import android.app.Activity;
import android.content.Intent;
import android.graphics.PixelFormat;
import android.net.sip.SipAudioCall;
import android.net.wifi.p2p.WifiP2pManager;
import android.os.Bundle;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.app.Service;

import example.com.chatheads.ChatHeadService.*;

public class MainActivity extends Activity {
private final int xx = 500;
private final int yy = 500;

Button startService,stopService, moveService;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
startService=(Button)findViewById(R.id.startService);
stopService=(Button)findViewById(R.id.stopService);
moveService=(Button)findViewById(R.id.moveService);

startService.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
startService(new Intent(getApplication(), ChatHeadService.class));
//startService(new Intent(getApplication(), HepUstte.class));

}
});
stopService.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
stopService(new Intent(getApplication(), ChatHeadService.class));

}
});

moveService.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
//System.out.println("Hello");

ChatHeadService inst = new ChatHeadService();
inst.UpdateEmployee();

}
});

}

and here is the chatheadservice class

package example.com.chatheads;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.os.CountDownTimer;
import android.os.IBinder;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;

import android.app.Activity;
import android.content.Intent;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.widget.Button;

public class ChatHeadService extends Service {
public WindowManager windowManager;
public ImageView chatHead;
WindowManager.LayoutParams params;

int xi ;
int yi ;

@Override
public void onCreate() {
super.onCreate();

System.out.println("Hello2");

windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);

chatHead = new ImageView(this);
chatHead.setImageResource(R.drawable.face1);

params = new WindowManager.LayoutParams(
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.TYPE_PHONE,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
PixelFormat.TRANSLUCENT);

params.gravity = Gravity.TOP | Gravity.LEFT;
params.x = 0;
params.y = 100;

chatHead.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
params.x = xi;
params.y = yi;

windowManager.updateViewLayout(chatHead, params);
}

});
windowManager.addView(chatHead, params);

}

public void MoveHead(){

System.out.println("Hello");

WindowManager.LayoutParams params = (WindowManager.LayoutParams) chatHead.getLayoutParams();

params.x = 100;
params.y = 300;

windowManager.updateViewLayout(chatHead, params);
}

@Override
public void onDestroy() {
super.onDestroy();
if (chatHead != null)
windowManager.removeView(chatHead);
}

@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
}