android 自定义控件以及自定义view学习（随机验证码生成）

在上一篇的博客中介绍了自定义控件的属性，详情见  android 自定义控件属性（TypedArray以及attrs解释）。那么在这基础上实现随机验证码生成，里面的代码是自定义控件以及涉及到自定义view绘画。

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1、先看实现的效果图

看到这个效果图是不是感觉还可以。那么就看看源码吧。

2、attr文件

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <attr name="titleText" format="string" />
    <attr name="titleTextColor" format="color" />
    <attr name="titleTextSize" format="dimension" />

    <declare-styleable name="AuthCodeView">
        <attr name="titleText" />
        <attr name="titleTextColor" />
        <attr name="titleTextSize" />
    </declare-styleable>

</resources>

3、布局layout

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:authcodeview="http://schemas.android.com/apk/res/com.example.authcodeview"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <com.example.authcodeview.view.AuthCodeView
            android:id="@+id/AuthCodeView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="10dp"
            authcodeview:titleText="3712"
            authcodeview:titleTextColor="#00ffff"
            authcodeview:titleTextSize="40sp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="点击验证码，换一张" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="输入验证码" />

        <EditText
            android:id="@+id/editText1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ems="10"
            android:inputType="number" >

            <requestFocus />
        </EditText>
    </LinearLayout>

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="验证" />

</LinearLayout>

4、自定义AuthCodeView.class

继承View，重写了
onMeasure(int widthMeasureSpec, int heightMeasureSpec)
onDraw(Canvas canvas)方法。
看代码，有详细注释了。

package com.example.authcodeview.view;

import java.util.Random;

import com.example.authcodeview.R;

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;

public class AuthCodeView extends View
{
	// 点数设置
	public static final int POINT_NUM = 100;
	// 线段数设置
	public static final int LINE_NUM = 2;
	//文本
	private String mTitleText;
	// 文本的颜色
	private int mTitleTextColor;
	// 文本的大小
	private int mTitleTextSize;
	
	String[] mCheckNum = new String[4];
	Random random = new Random();
	
	//绘制时控制文本绘制的范围
	private Rect mBound;
	private Paint mPaint;

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

	public AuthCodeView(Context context)
	{
		this(context, null);
	}

	/**
	 * 获得我自定义的样式属性
	 * 
	 * @param context
	 * @param attrs
	 * @param defStyle
	 */
	public AuthCodeView(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);
		/**
		 * 获得我们所定义的自定义样式属性
		 */
		TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.AuthCodeView, defStyle, 0);
		
		//获取在attr文件下，名字为AuthCodeView的declare-styleable属性有几个
		int n = a.getIndexCount();
		for (int i = 0; i < n; i++)
		{
			int attr = a.getIndex(i);
			switch (attr)
			{
			//这个属性可以不要，因为都是随机产生
			case R.styleable.AuthCodeView_titleText:
				mTitleText = a.getString(attr);
				break;
			case R.styleable.AuthCodeView_titleTextColor:
				// 默认颜色设置为黑色
				mTitleTextColor = a.getColor(attr, Color.BLACK);
				break;
			case R.styleable.AuthCodeView_titleTextSize:
				// 默认设置为16sp，TypeValue也可以把sp转化为px
				mTitleTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(
						TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));
				break;

			}

		}
		a.recycle();
		
		mTitleText = randomText();

		/**
		 * 获得绘制文本的宽和高
		 */
		mPaint = new Paint();
		mPaint.setTextSize(mTitleTextSize);
		mBound = new Rect();
		mPaint.getTextBounds(mTitleText, 0, mTitleText.length(), mBound);

		this.setOnClickListener(new OnClickListener()
		{

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

		});

	}
	
	//随机产生验证码
	private String randomText()
	{
		StringBuffer sbReturn = new StringBuffer();
		for (int i = 0; i < 4; i++) {
			StringBuffer sb = new StringBuffer();
			int randomInt = random.nextInt(10);
			mCheckNum[i] = sb.append(randomInt).toString();
			sbReturn.append(randomInt);
		}
		
		return sbReturn.toString();
	}
	
	//获取验证码
	public String getAuthCode() {
		return mTitleText;
	}

	//重写这个方法，设置自定义view控件的大小
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
	{
		// super.onMeasure(widthMeasureSpec, heightMeasureSpec);

		int width = 0;
		int height = 0;

		/**
		 * 设置宽度
		 */
		int specMode = MeasureSpec.getMode(widthMeasureSpec);
		int specSize = MeasureSpec.getSize(widthMeasureSpec);
		switch (specMode)
		{
		case MeasureSpec.EXACTLY:// 明确指定了
			width = getPaddingLeft() + getPaddingRight() + specSize;
			break;
		case MeasureSpec.AT_MOST:// 一般为WARP_CONTENT
			width = getPaddingLeft() + getPaddingRight() + mBound.width();
			break;
		}

		/**
		 * 设置高度
		 */
		specMode = MeasureSpec.getMode(heightMeasureSpec);
		specSize = MeasureSpec.getSize(heightMeasureSpec);
		switch (specMode)
		{
		case MeasureSpec.EXACTLY:// 明确指定了
			height = getPaddingTop() + getPaddingBottom() + specSize;
			break;
		case MeasureSpec.AT_MOST:// 一般为WARP_CONTENT
			height = getPaddingTop() + getPaddingBottom() + mBound.height();
			break;
		}

		setMeasuredDimension(width, height);

	}

	@Override
	protected void onDraw(Canvas canvas)
	{
		//画背景颜色
		mPaint.setColor(Color.BLUE);
		canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint);
		
		//划线 
		mPaint.setColor(mTitleTextColor);
		int [] line;
		for(int i = 0; i < LINE_NUM; i ++)
		{
			//设置线宽
			mPaint.setStrokeWidth(5);
			line = getLine(getMeasuredHeight(), getMeasuredWidth());
            canvas.drawLine(line[0], line[1], line[2], line[3], mPaint);
        } 
		
		// 绘制小圆点
		int [] point; 
		int randomInt;
		for(int i = 0; i < POINT_NUM; i ++)    
		{
			//随机获取点的大小
			randomInt = random.nextInt(5);
			point = getPoint(getMeasuredHeight(), getMeasuredWidth());
            canvas.drawCircle(point[0], point[1], randomInt, mPaint);
        }

		//绘制验证控件上的文本
		int dx = 20; 
		for(int i = 0; i < 4; i ++){
			canvas.drawText("" + mCheckNum[i],dx, getHeight() / 2 + getPositon(mBound.height() / 2), mPaint);
            dx += (getWidth() / 2 - mBound.width() / 2) + i / 5 + 20;
        }
//		canvas.drawText(mTitleText, getWidth() / 2 - mBound.width() / 2, getHeight() / 2 + mBound.height() / 2, mPaint);
	}
	
	//计算验证码的绘制y点位置
	private  int getPositon(int height) {
		int tempPositoin = (int) (Math.random() * height);
		if (tempPositoin < 20) {
			tempPositoin += 20;
		}
		return tempPositoin;
	}
	
	// 随机产生点的圆心点坐标
	public static int[] getPoint(int height, int width) {
		int[] tempCheckNum = { 0, 0, 0, 0 };
		tempCheckNum[0] = (int) (Math.random() * width);
		tempCheckNum[1] = (int) (Math.random() * height);
		return tempCheckNum;
	}
	
	//随机产生划线的起始点坐标和结束点坐标
	public static int[] getLine(int height, int width) {
		int[] tempCheckNum = { 0, 0, 0, 0 };
		for (int i = 0; i < 4; i += 2) {
			tempCheckNum[i] = (int) (Math.random() * width);
			tempCheckNum[i + 1] = (int) (Math.random() * height);
		}
		return tempCheckNum;
	}
}

5、在MainActivity中怎么使用这个自定义AuthCodeView

package com.example.authcodeview;

import com.example.authcodeview.view.AuthCodeView;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener
{

	private AuthCodeView mauthCodeView;
	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		initUI();
	}

	private void initUI() {
		mauthCodeView = (AuthCodeView)findViewById(R.id.AuthCodeView);
		findViewById(R.id.button1).setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.button1:
			EditText editText = (EditText)findViewById(R.id.editText1);
			String codeString = editText.getText().toString().trim();
			if (codeString.equals(mauthCodeView.getAuthCode())) {
				Toast.makeText(this, "验证码验证正确！", Toast.LENGTH_LONG).show();
			}else {
				Toast.makeText(this, "验证码错误！", Toast.LENGTH_LONG).show();
			}
			break;

		default:
			break;
		}
		
	}


}

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