自定义view实现数字点击变换功能

package com.bwie.chentong.rikao0928;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;

import java.util.HashSet;
import java.util.Random;
import java.util.Set;

public class MyTextView extends View{
private String mTitleText;
private int mTitleTextColor;
private int mTitleTextSize;

/**
* 画笔
*/
private Paint mPaint;
/**
* view的矩形背景
*/
private Rect mBound;
public MyTextView(Context context) {
this(context,null);
}

public MyTextView(Context context, AttributeSet attrs) {
this(context, attrs,0);
}

public MyTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.MyTextView, defStyleAttr, 0);
mTitleText = randomText(); //初始化显示的数字

for (int i = 0; i < a.getIndexCount(); i++) {
int attr = a.getIndex(i);
switch (attr) {
case R.styleable.MyTextView_titleText:
mTitleText = a.getString(attr);
break;
case R.styleable.MyTextView_titleTextColor:
mTitleTextColor = a.getColor(attr, Color.BLACK);
break;
case R.styleable.MyTextView_titleTextSize:
//设置默认大小为16
mTitleTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));
break;
}
}
//将TypedArray对象回收
a.recycle();

/**
* 初始化画笔
*/
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setTextSize(mTitleTextSize);
mPaint.setColor(mTitleTextColor);
mBound = new Rect();
mPaint.getTextBounds(mTitleText, 0, mTitleText.length(), mBound);

/**
* 模仿点击换验证码
*/
this.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
mTitleText = randomText();
postInvalidate();
}
});
}

/**
* 获取四位随机数验证码
*
* @return
*/
private String random
4000
Text() {
Random random = new Random();
Set<Integer> set = new HashSet<Integer>();
while (set.size() < 4) {
int randomInt = random.nextInt(10);
set.add(randomInt);
}
StringBuffer sb = new StringBuffer();
for (Integer i : set) {
sb.append("" + i);
}

return sb.toString();
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

/**
* 处理当宽高都是wrap_content的情况
*/
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);

int width = 0;
int height = 0;

if (widthMode == MeasureSpec.EXACTLY) {
width = widthSize;
} else {
mPaint.setTextSize(mTitleTextSize);
mPaint.getTextBounds(mTitleText, 0, mTitleText.length(), mBound);
float textWidth = mBound.width();
int desired = (int) (getPaddingLeft() + textWidth + getPaddingRight());
width = desired;
}
if (heightMode == MeasureSpec.EXACTLY) {
height = heightSize;
} else {
mPaint.setTextSize(mTitleTextSize);
mPaint.getTextBounds(mTitleText, 0, mTitleText.length(), mBound);
float textWidth = mBound.height();
int desired = (int) (getPaddingTop() + textWidth + getPaddingBottom());
height = desired;
}
setMeasuredDimension(width, height);
}

@Override
protected void onDraw(Canvas canvas) {
/**
* 绘制文字和矩形
*/
mPaint.setColor(Color.YELLOW);
canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint);

mPaint.setColor(mTitleTextColor);
canvas.drawText(mTitleText, getWidth() / 2 - mBound.width() / 2, getHeight() / 2 + mBound.height() / 2, mPaint);
}

}