GestureListnerをDrawViewで動かすための最低限のコード

package com.example.left_and_right;

import android.app.Activity;

import android.content.Context;

import android.graphics.Canvas;

import android.os.Bundle;

import android.view.GestureDetector;

import android.view.GestureDetector.OnGestureListener;

import android.view.MotionEvent;

import android.view.View;

public class MainActivity extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

DrawView view = new DrawView(getApplication());

setContentView(view);

}

}

class DrawView extends View implements OnGestureListener{

GestureDetector gestureDetector;

public DrawView(Context context) {

super(context);

gestureDetector = new GestureDetector(getContext(), this);

}

public void onDraw(Canvas canvas){

}

@Override

public boolean onTouchEvent(MotionEvent event){

gestureDetector.onTouchEvent(event);

return true;

}

@Override

public boolean onScroll(MotionEvent event, MotionEvent e2, float distanceX,float distanceY){

return true;

}

@Override

public boolean onDown(MotionEvent e) {

return true;

}

@Override

public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,float velocityY){

return true;

}

@Override

public void onShowPress(MotionEvent e) {

}

@Override

public boolean onSingleTapUp(MotionEvent e) {

return true;

}

@Override

public void onLongPress(MotionEvent e) {

}

}