GestureDetector--手势识别初体验（一）

双击爆炸；右向左滑动←；左向右滑动→;
MainActivity.class

package com.superxingyun.gestruedetectordemo;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    ImageView img;
    GestureDetector gestureDetector;
    class MyGestureListen extends SimpleOnGestureListener{
        @Override//滑动事件
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            if (e1.getX() - e2.getX() > 50){
                Toast.makeText(MainActivity.this, "←←←←←←←←←←", Toast.LENGTH_SHORT).show();
            }else if (e2.getX() - e1.getX() >50){
                Toast.makeText(MainActivity.this, "→→→→→→→→→→", Toast.LENGTH_SHORT).show();
            }
            return super.onFling(e1, e2, velocityX, velocityY);
        }

     /*   @Override//单击事件
        public boolean onDown(MotionEvent e) {
            Toast.makeText(MainActivity.this, "...........", Toast.LENGTH_SHORT).show();
            return super.onDown(e);
        }*/

        @Override//双击事件
        public boolean onDoubleTap(MotionEvent e) {
            Toast.makeText(MainActivity.this, "BOOM", Toast.LENGTH_SHORT).show();
            return super.onDoubleTap(e);
        }
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        gestureDetector = new GestureDetector(MainActivity.this, new MyGestureListen());

        img = (ImageView) findViewById(R.id.img);
        img.setOnTouchListener(new View.OnTouchListener() {
            @Override//可以捕获到触摸屏幕发生的Event事件
            public boolean onTouch(View vew, MotionEvent motionEvent) {
                gestureDetector.onTouchEvent(motionEvent);
                return true;
            }
        });
    }
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    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:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.superxingyun.gestruedetectordemo.MainActivity">


    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@mipmap/i"
        android:layout_centerVertical="true"
        android:id="@+id/img" />
RelativeLayout>