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触摸事件,可以包含多点触摸,也可以使用捏合手势缩放,并且放大图片;

多点触摸的实现:

num =motionEvent.getPointerCount()//使用MotionEvent的此方法来获取当前手指的数量.

然后使用一个循环,进行手指数据的遍历:

id = 0;

while(id < num){
int ptridx = motionEvent.getPointerId(id);
float x1 = motionEvent.getX(ptridx);
float y1 = motionEvent.getY(ptridx);

Log.d(TAG,"x1="+x1+",y1="+y1);//手指的屏幕坐标

float pressure = motionEvent.getPressure(ptridx);//压力
float size = motionEvent.getSize(ptridx);//手指尺寸

id++;//下一根手指
}

其余的全部代码:

package com.lanxin.testtouch;

import android.graphics.Matrix;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnTouchListener {

    private static final String TAG = "TouchLog";
    float y = 0;
    float x = 0;
    ImageView img;
    ScaleGestureDetector mScaleGesture;
    float mScaleFloat = 1f;
    Matrix matrix = new Matrix();
    TextView text2;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //RelativeLayout relativeLayout = (RelativeLayout)findViewById(R.id.relativeLayout);//使用relativeLayout来绑定触摸事件
        //relativeLayout.setOnTouchListener(this);//添加事件监听

        //捏合手势的演示
        text2 = (TextView)findViewById(R.id.text2);
        img = (ImageView)findViewById(R.id.images1);
        mScaleGesture = new ScaleGestureDetector(this, new ScaleGestureDetector.OnScaleGestureListener() {
            @Override
            public boolean onScale(ScaleGestureDetector detector) {

                mScaleFloat *= detector.getScaleFactor();

                String str = "";

                str = "比例:"+detector.getScaleFactor()+" mScaleFloat:"+mScaleFloat+"\n";

                mScaleFloat = Math.max(0.1f,Math.min(mScaleFloat,5.0f));//图像比例,最小0.1,最大5

                str += "  mScaleFloat:"+mScaleFloat;
                text2.setText(str);

                matrix.setScale(mScaleFloat, mScaleFloat);
                img.setImageMatrix(matrix);
                img.invalidate();

                return true;//这里一定要返回真,否则不会继续监听事件
            }

            @Override
            public boolean onScaleBegin(ScaleGestureDetector scaleGestureDetector) {
                return true;//这里一定要返回真,否则不会继续监听事件
            }

            @Override
            public void onScaleEnd(ScaleGestureDetector scaleGestureDetector) {

            }
        });
        //捏合手势演示结束

    }

    public boolean onTouchEvent(MotionEvent event){
        mScaleGesture.onTouchEvent(event);//为捏合手势绑定触摸事件

        Log.d(TAG,"onTouchEvent");

        return true;
    }

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        //多点触摸的代码演示:
        int num = motionEvent.getPointerCount();
        int id = 0;
        while (id < num){
            int ptridx = motionEvent.getPointerId(id);
            float x1 = motionEvent.getX(ptridx);
            float y1 = motionEvent.getY(ptridx);

            Log.d(TAG,"x1="+x1+",y1="+y1);//手指的屏幕坐标

            float pressure = motionEvent.getPressure(ptridx);//压力
            float size = motionEvent.getSize(ptridx);//手指尺寸

            id++;//下一根手指
        }


        String action = "";
        switch (motionEvent.getAction()){
            case 0:
                x =motionEvent.getX();
                y = motionEvent.getY();
                action = "按下";
                break;
            case 1:
                if (motionEvent.getX() - x < -50){
                    action = "放开:往左边移动["+(motionEvent.getX() - x) +"]";//小于-50肯定是往左滑动
                }else if (motionEvent.getX() - x > 50){
                    action = "放开:往右边移动["+(motionEvent.getX() - x) +"]";//大于50肯定是往右边滑动
                }else {
                    action = "没有移动";
                }

                break;
            case 2:
                action = "移动";
                break;
            default:
                action = "其他:"+motionEvent.getAction();
                break;
        }

        String buff = "Aciton:"+action+"\n";
        buff += "Location:x=>"+x+" y=>"+y+"\n";
        buff += "EdgeFlags:"+motionEvent.getEdgeFlags()+"\n";
        buff += "pressure:"+motionEvent.getPressure()+"\n";
        buff += "size:"+motionEvent.getSize()+"\n";
        buff += "downtime:"+motionEvent.getDownTime()+"\n";
        buff += "eventtime:"+motionEvent.getEventTime()+"\n";
        buff += "Elapsed:"+ (motionEvent.getEventTime() - motionEvent.getDownTime());

        Log.d(TAG,buff.toString());

        return true;
    }
}

xml布局文件的代码:

<?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:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:id="@+id/relativeLayout"
    tools:context=".MainActivity">

    <TextView
        android:text=""
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/text2"/>
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/images1"
        android:src="@drawable/wewer"
        android:layout_marginTop="50dp"
        android:scaleType="matrix"/>

</RelativeLayout>