Plate Of Code: How to control arduino connected Servo motor from an android app Over Bluetooth connection ?

You can get your connection and device assembling from another stuffs.Here I place My code which i developed. which may useful for You.

For Any Query comment below ..

//Arduino code..

       
#include <Servo.h>
int pos=0;
int servoPin=9;
int servoDelay=25;
Servo myPointer;

char data = 0;                //Variable for storing received data
void setup() 
{
  Serial.begin(9600);         //Sets the data rate in bits per second (baud) for serial data transmission
  //pinMode(13, OUTPUT);        //Sets digital pin 13 as output pin
  myPointer.attach(servoPin);
}
void loop()
{
  if(Serial.available() > 0)  // Send data only when you receive data:
  {
    while(Serial.available()==0){}
    pos=Serial.parseInt();
    myPointer.write(pos);
  }
}

//code FOR android application

AndroidManifest.xml file

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.kiit1.audrinoblutooth">
    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="17" />
    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.example.kiit1.audrinoblutooth.MainActivity">

    <EditText android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:inputType="number"
              android:ems="10"  
              android:layout_alignParentTop="true"  
              android:layout_centerHorizontal="true" 
              android:layout_marginTop="184dp"  
              android:id="@+id/editText" />

    <Button   android:text="Move"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"  
              android:layout_alignParentBottom="true"
              android:layout_alignStart="@+id/button"
              android:layout_marginBottom="82dp"
              android:id="@+id/button2" />

    <Button   android:text="Button" 
              android:layout_width="wrap_content" 
              android:layout_height="wrap_content"
              android:layout_marginTop="45dp" 
              android:id="@+id/button"
              android:layout_alignParentTop="true" 
              android:layout_centerHorizontal="true" />
</RelativeLayout>

for mainActivity

package com.example.kiit1.audrinoblutooth;

import android.app.AlertDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.os.ParcelUuid;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Set;

public class MainActivity extends AppCompatActivity {
    private OutputStream outputStream;
    private InputStream inStream;

    @Override    protected void onCreate(Bundle savedInstanceState) {
        int position=0;
        try {
            BluetoothAdapter blueAdapter = BluetoothAdapter.getDefaultAdapter();
            if (blueAdapter != null) {

                if (blueAdapter.isEnabled()) {
                    Set<BluetoothDevice> bondedDevices = blueAdapter.getBondedDevices();

                    if (bondedDevices.size() > 0) {
                        Object[] devices = (Object[]) bondedDevices.toArray();
                        Toast.makeText(getBaseContext(), devices.length+"", Toast.LENGTH_LONG).show();
                        BluetoothDevice device = (BluetoothDevice) devices[position];
                        ParcelUuid[] uuids = device.getUuids();
                        BluetoothSocket socket = device.createRfcommSocketToServiceRecord(uuids[0].getUuid());
                        socket.connect();
                        outputStream = socket.getOutputStream();
                        inStream = socket.getInputStream();
                    }

                    Log.e("error", "No appropriate paired devices.");
                } else {
                    Log.e("error", "Bluetooth is disabled.");
                }
            }
        }catch(Exception e){
            e.printStackTrace();
            Toast.makeText(getBaseContext(), "SETUP Failure", Toast.LENGTH_LONG).show();
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            //Creating dialog box            AlertDialog alert = builder.create();
            //Setting the title manually            alert.setTitle("Error");
            String sErr=e.toString();
            alert.setMessage(sErr);
            alert.show();

        }


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button2=(Button)findViewById(R.id.button2);
        final EditText editText=(EditText)findViewById(R.id.editText);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override            public void onClick(View v) {
             String str= editText.getText().toString();
                try {
                    write(str);
                }catch(Exception e){
                    Toast.makeText(getBaseContext(), "Connection Failure", Toast.LENGTH_LONG).show();
                }
            }
        });
    }

    public void write(String s) throws IOException {
        outputStream.write(s.getBytes());
    }
}