Aplikacja symulująca joystick nie włącza się.

 js = new JoyStickClass(getApplicationContext(), layout_joystick, R.drawable.image_button);
        js.setStickSize(150, 150);
        js.setLayoutSize(500, 500);
        js.setLayoutAlpha(150);
        js.setStickAlpha(100);
        js.setOffset(90);
        js.setMinimumDistance(50);

         layout_joystick.setOnTouchListener(new OnTouchListener() {
            public boolean onTouch(View arg0, MotionEvent arg1) {
                js.drawStick(arg1);
                if(arg1.getAction() == MotionEvent.ACTION_DOWN
                        || arg1.getAction() == MotionEvent.ACTION_MOVE) {
                    textView1.setText("X : " + String.valueOf(js.getX()));
                    textView2.setText("Y : " + String.valueOf(js.getY()));
                    textView3.setText("Angle : " + String.valueOf(js.getAngle()));
                    textView4.setText("Distance : " + String.valueOf(js.getDistance()));

                    int direction = js.get8Direction();
                    if(direction == JoyStickClass.STICK_UP) {
                        textView5.setText("Direction : Up");
                    } else if(direction == JoyStickClass.STICK_UPRIGHT) {
                        textView5.setText("Direction : Up Right");
                    } else if(direction == JoyStickClass.STICK_RIGHT) {
                        textView5.setText("Direction : Right");
                    } else if(direction == JoyStickClass.STICK_DOWNRIGHT) {
                        textView5.setText("Direction : Down Right");
                    } else if(direction == JoyStickClass.STICK_DOWN) {
                        textView5.setText("Direction : Down");
                    } else if(direction == JoyStickClass.STICK_DOWNLEFT) {
                        textView5.setText("Direction : Down Left");
                    } else if(direction == JoyStickClass.STICK_LEFT) {
                        textView5.setText("Direction : Left");
                    } else if(direction == JoyStickClass.STICK_UPLEFT) {
                        textView5.setText("Direction : Up Left");
                    } else if(direction == JoyStickClass.STICK_NONE) {
                        textView5.setText("Direction : Center");
                    }
                }
                return true;
            }
        }

 E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.android.bluetoothchat, PID: 10076
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.bluetoothchat/com.example.android.bluetoothchat.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.ViewGroup$LayoutParams android.view.ViewGroup.getLayoutParams()' on a null object reference
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2450)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
                      at android.app.ActivityThread.access$1200(ActivityThread.java:165)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1373)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:135)
                      at android.app.ActivityThread.main(ActivityThread.java:5593)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at java.lang.reflect.Method.invoke(Method.java:372)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
                   Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.ViewGroup$LayoutParams android.view.ViewGroup.getLayoutParams()' on a null object reference
                      at com.example.android.bluetoothchat.JoyStickClass.<init>(JoyStickClass.java:54)
                      at com.example.android.bluetoothchat.MainActivity.onCreate(MainActivity.java:79)
                      at android.app.Activity.performCreate(Activity.java:6102)
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2403)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) 
                      at android.app.ActivityThread.access$1200(ActivityThread.java:165) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1373) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:135) 
                      at android.app.ActivityThread.main(ActivityThread.java:5593) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at java.lang.reflect.Method.invoke(Method.java:372) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 

public JoyStickClass (Context context, ViewGroup layout, int stick_res_id) {
        mContext = context;

        stick = BitmapFactory.decodeResource(mContext.getResources(), stick_res_id);

        stick_width = stick.getWidth();
        stick_height = stick.getHeight();

        draw = new DrawCanvas(mContext);
        paint = new Paint();
        mLayout = layout;
       params = mLayout.getLayoutParams();
    }

  <RelativeLayout
        android:id="@+id/layout_joystick"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:layout_marginRight="36dp"
        android:background="@drawable/image_button_bg" >
    </RelativeLayout>