【Android自定义View】随机数按钮

参考了多个大神的博客，自己也就做了个。

自定义一个控件，一般需要准备以下内容

1.设置对应属性

2.继承View（一般情况下，需求不一样也可以是别的）

3.重写几个函数

做完以上三点，基本一个个性化的控件就完成了

先来第一步

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent" android:layout_height="match_parent">
    <com.tools.CT
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        custom:Ctext="你好"
        android:padding="10dp"
        android:layout_centerInParent="true"
        custom:Ccolor="#555555"
        custom:Csize="20dp"
        />
</LinearLayout>

其中

com.tools.CT 部分就是自定义控件的布局部分

注意：

xmlns:custom="http://schemas.android.com/apk/res-auto"

是必不可少的部分，这也是前提

而com.tools.CT 就是指向  继承View的CT类

package com.tools;

//import android.app.Activity;
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 android.view.View;
//import android.widget.TextView;

import com.example.administrator.myapplication.R;

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

/**
 * Created by Administrator on 2015/9/12.
 */
public class CT extends View{

    private String ctext;
    private int ccolor;
    private int csize;

    private Rect mbound;
    private Paint mpaint;

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

    public CT(Context context){
        this(context,null);
    }
    public CT(Context context,AttributeSet attrs,int style){
        super(context,attrs,style);
        TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CT, style, 0);
        int n = a.getIndexCount();
        for (int i = 0; i < n; i++)
        {
            int attr = a.getIndex(i);
            switch (attr)
            {
                case R.styleable.CT_Ctext:
                    ctext = a.getString(attr);
                    break;
                case R.styleable.CT_Ccolor:
                    // 默认颜色设置为黑色
                    ccolor = a.getColor(attr, Color.BLACK);
                    break;
                case R.styleable.CT_Csize:
                    // 默认设置为16sp，TypeValue也可以把sp转化为px
                    csize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(
                            TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));
                    break;

            }

        }
        a.recycle();

        /**
         * 获得绘制文本的宽和高
         */
        mpaint = new Paint();
        mpaint.setTextSize(csize);
        // mPaint.setColor(mTitleTextColor);
        mbound = new Rect();
        mpaint.getTextBounds(ctext, 0, ctext.length(), mbound);

        this.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v)
            {
                ctext = randomText();
                postInvalidate();
            }

        });
    }

    private String  randomText(){
        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) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int width;
        int height ;
        if (widthMode == MeasureSpec.EXACTLY)
        {
            width = widthSize;
        } else
        {
            mpaint.setTextSize(csize);
            mpaint.getTextBounds(ctext, 0, ctext.length(), mbound);
            float textWidth = mbound.width();
            int desired = (int) (getPaddingLeft() + textWidth + getPaddingRight());
            width = desired;
        }

        if (heightMode == MeasureSpec.EXACTLY)
        {
            height = heightSize;
        } else
        {
            mpaint.setTextSize(csize);
            mpaint.getTextBounds(ctext, 0, ctext.length(), mbound);
            float textHeight = mbound.height();
            int desired = (int) (getPaddingTop() + textHeight + getPaddingBottom());
            height = desired;
        }



        setMeasuredDimension(width, height);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        mpaint.setColor(Color.BLUE);
        canvas.drawRect(0,0,getMeasuredWidth(),getMeasuredHeight(),mpaint);
        mpaint.setColor(ccolor);
        canvas.drawText(ctext,getWidth()/2-mbound.width()/2,getHeight()/2+mbound.height()/2,mpaint);
    }
}

其中

重写

onMeasure 和 onDraw 是重写的主要内容,包含着属性的设置

</pre><pre name="code" class="java">

<pre style="background-color:#2b2b2b;color:#a9b7c6;font-family:'宋体';font-size:9.0pt;"><span style="color:#cc7832;">this</span>.setOnClickListener(<span style="color:#cc7832;">new </span>OnClickListener()
{

    <span style="color:#bbb529;">@Override
</span><span style="color:#bbb529;">    </span><span style="color:#cc7832;">public void </span><span style="color:#ffc66d;">onClick</span>(View v)
    {
        <span style="color:#9876aa;">ctext </span>= randomText()<span style="color:#cc7832;">;
</span><span style="color:#cc7832;">        </span>postInvalidate()<span style="color:#cc7832;">;
</span><span style="color:#cc7832;">    </span>}

})<span style="color:#cc7832;">;</span>

其中加入点击监听，以此响应随机函数

进而随机显示内容

从而完成随机按钮