Android自定义控件深入学习 Android生成随机验证码

在上一篇的文章中介绍了自定义控件的属性，详情见《详解Android自定义控件属性TypedArray以及attrs》。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。
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;
}
}
}

源码下载：Android生成随机验证码Demo

以上就是本文的全部内容，希望对大家的学习有所帮助。

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