Android 手势

今天，我们要讲的是Android里的手势，为了方便理解，我们做了一个dome

用左滑右滑的手势实现的图片的切换

效果如下：

废话不多说，我们直接上代码

package com.example.myas_020;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.ViewFlipper;

public class MainActivity extends AppCompatActivity {

    private ViewFlipper vf_main_image;
    private int images[]={R.drawable.s1,R.drawable.s2,R.drawable.s3};
    private GestureDetector gd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        vf_main_image = (ViewFlipper) findViewById(R.id.vf_main_image);
        for (int i = 0; i <images.length ; i++) {
            ImageView iv=new ImageView(this);
            iv.setImageResource(images[i]);
            vf_main_image.addView(iv);
        }

        //实例化手势检测器类
         gd = new GestureDetector(this, new GestureDetector.OnGestureListener() {
            //按下
             @Override
            public boolean onDown(MotionEvent e) {
                return false;
            }

             //按下，但是还未抬起
            @Override
            public void onShowPress(MotionEvent e) {

            }
             //轻按，按一下，立刻抬起
            @Override
            public boolean onSingleTapUp(MotionEvent e) {
                return false;
            }
             //滚动
            @Override
            public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
                return false;
            }
             //长按
            @Override
            public void onLongPress(MotionEvent e) {

            }
             //拖动
            @Override
            public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
                if(e2.getX()-e1.getX()>200){
                    Toast.makeText(MainActivity.this, "右滑,上一张", Toast.LENGTH_SHORT).show();
                    vf_main_image.showPrevious();
                    //左进右出
                    vf_main_image.setInAnimation(MainActivity.this,R.anim.left_in);
                    vf_main_image.setOutAnimation(MainActivity.this,R.anim.right_out);
                }if(e1.getX()-e2.getX()>200){
                    Toast.makeText(MainActivity.this, "左滑,下一张", Toast.LENGTH_SHORT).show();
                    vf_main_image.showNext();
                    //左出右进
                    vf_main_image.setInAnimation(MainActivity.this,R.anim.right_in);
                    vf_main_image.setOutAnimation(MainActivity.this,R.anim.left_out);
                }
                return false;
            }
        });
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return gd.onTouchEvent(event);
    }
}

还有四个动画的代码：

左滑进

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:fillAfter="true"
    android:duration="1500"
    >
    <translate
        android:fromXDelta="-100%p"
        android:toXDelta="0"
        ></translate>

    <rotate
        android:fromDegrees="0"
        android:toDegrees="360"
        android:pivotX="100%"
        android:pivotY="50%"
        ></rotate>

</set>

左滑出

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:fillAfter="true"
    android:duration="1500"
    >
    <translate
        android:fromXDelta="0"
        android:toXDelta="100%p"
        ></translate>

    <rotate
        android:fromDegrees="0"
        android:toDegrees="360"
        android:pivotX="0"
        android:pivotY="50%"
        ></rotate>

</set>

右滑进 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:fillAfter="true"
    android:duration="1500"
    >
    <translate
        android:fromXDelta="100%p"
        android:toXDelta="0"
        ></translate>
    <rotate
        android:fromDegrees="0"
        android:toDegrees="360"
        android:pivotX="100%"
        android:pivotY="50%"
        ></rotate>
</set>

右滑出

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:fillAfter="true"
    android:duration="1500"
    >
    <translate
        android:fromXDelta="0"
        android:toXDelta="-100%p"
        ></translate>
    <rotate
        android:fromDegrees="0"
        android:toDegrees="360"
        android:pivotX="0"
        android:pivotY="50%"
        ></rotate>
</set>