多点触控

//字体的放大缩小package com.xiaoyu.multi_touch;import android.content.Context;import android.util.AttributeSet;import android.view.MotionEvent;import android.widget.TextView;import android.widget.Toast;/** * 1.类的用途: * 2.作者:段玉 * 3.时间:2017/2/10 11 * 4.邮箱:1239959892@QQ.com */public class ScaleTextview extends TextView {    //获取两个指头之间的距离    PRivate double olddistance;    private float textSize;    public ScaleTextview(Context context) {        super(context);    }    public ScaleTextview(Context context, AttributeSet attrs) {        super(context, attrs);    }    public ScaleTextview(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getActionMasked()){            case MotionEvent.ACTION_POINTER_DOWN:            {                //获取字体大小                if (textSize == 0){                    textSize = this.getTextSize();                    //吐司                    Toast.makeText(getContext(),textSize+"",Toast.LENGTH_SHORT).show();                }                //获取两指之间的距离                olddistance = getdistance(event);            }                break;            case MotionEvent.ACTION_MOVE:            {                //判断当前有几个手指                if (event.getPointerCount() >= 2){                    //获取滑动时两指之间的距离                    double distance = getdistance(event);                    //获取按下时 和滑动时  两指之间距离的比例                    Zoom(distance / olddistance);                    //重置下按下的距离                    olddistance = distance;                }            }                break;        }        return true;    }    /**     * 重新设置字体大小     * @param v     */    private void Zoom(double v) {        //对textview控件重新设置字体大小        textSize = (float) (textSize * v);        //重新设置textview        this.setTextSize(px2sp(getContext(),textSize));    }    /**     * 获取两指之间距离     * @param event     * @return     */    public double getdistance(MotionEvent event){        float x = event.getX(0);        float x1 = event.getX(1);        float y = event.getY(0);        float y1 = event.getY(1);        //根据勾股定理 取平方根        double sqrt = Math.sqrt((x - x1) * (x - x1) + (y - y1) * (y - y1));        return sqrt;    }    /**     * 将px值转换为sp值,保证文字大小不变     * @param context     * @param pxValue     * @return     */    public int px2sp(Context context,float pxValue){        float scaledDensity = context.getResources().getDisplayMetrics().scaledDensity;        return (int) (pxValue / scaledDensity + 0.5f);    }}//简单的xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <com.baway.multi_touch.ScaleTextview        android:gravity="center"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:textSize="30dp"        android:text="浅宝宝_筱玉"/></LinearLayout>//图片的放大缩小
package com.xiaoyu.multi_touch;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Matrix;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;/** * 1.类的用途: * 2.作者:段玉 * 3.时间:2017/2/10 14 * 4.邮箱:1239959892@qq.com */public class ScaleImageview extends View {    private Bitmap bitmap;    Matrix matrix = new Matrix();    private double olddistance;    public ScaleImageview(Context context) {        super(context);        init();    }    public ScaleImageview(Context context, AttributeSet attrs) {        super(context, attrs);        init();    }    private void init() {        bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.nuan_bao);    }    public ScaleImageview(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init();    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawBitmap(bitmap,matrix,null);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getActionMasked()){            case MotionEvent.ACTION_POINTER_DOWN:            {                //获取两指之间距离                olddistance = getdistance(event);            }                break;            case MotionEvent.ACTION_MOVE:            {                if (event.getPointerCount() >= 2){                    //获取移动中两指之间的距离                    double distance = getdistance(event);                    //获取按下时 和滑动时  两指之间距离的比例                    zoom((float) (distance / olddistance));                    olddistance = distance;                }            }                break;        }        return true;    }    /**     * 重新绘制图片     * @param v     */    private void zoom(float v) {        //矩阵缩放        matrix.postScale(1.0f * v, 1.0f * v);        //重新绘制        postInvalidate();    }    //获取两指之间的距离    public double getdistance(MotionEvent event){        float x = event.getX(0);        float x1 = event.getX(1);        float y = event.getY(0);        float y1 = event.getY(1);        //取平方根        double sqrt = Math.sqrt((x - x1) * (x - x1) + (y - y1) * (y - y1));        return sqrt;    }}