Android_双指缩放TextView

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这里写图片描述

xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    >    <TextView         android:id="@+id/control_textView"        android:text="字体可缩放哦"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerInParent="true"/></RelativeLayout>

activity

package com.lxf;import android.app.Activity;import android.os.Bundle;import android.util.FloatMath;import android.view.MotionEvent;import android.widget.TextView;/** * @address BeiJing * @author LiXufei * @function  TextViwe缩放 */public class cControlTextView extends Activity{    private TextView view;    private int textSize = 0;       private float oldDist = 0;    private int mode = 0;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.android_control_textview);        view = (TextView) findViewById(R.id.control_textView);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        if (textSize == 0) {            textSize = (int) view.getTextSize();        }        switch (event.getAction()&MotionEvent.ACTION_MASK) {        case MotionEvent.ACTION_DOWN:            mode = 1;            break;        case MotionEvent.ACTION_UP:            mode = 0;            break;        case MotionEvent.ACTION_POINTER_DOWN:            mode += 1;            oldDist = spacing(event);            break;        case MotionEvent.ACTION_POINTER_UP:            mode -= 1;            break;        case MotionEvent.ACTION_MOVE:            if (mode == 2) {                float newDist = spacing(event);                if (newDist > oldDist+1) {  //放大                    draw(newDist/oldDist);                    oldDist = newDist;                }                if (newDist < oldDist-1) {      //缩小                    draw(newDist/oldDist);                    oldDist = newDist;                }            }            break;        }        return true;    }    //绘制TextView    private void draw(float f){        view.setTextSize(textSize*=f);    }    //获取两指间的距离    @SuppressWarnings("unused")    private float spacing(MotionEvent event){        float x=event.getX(0) - event.getX(1);        float y=event.getY(0) - event.getY(1);        return FloatMath.sqrt(x * x + y * y);    }}

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