Android自定义控件深入学习 Android生成随机验证码

概述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。

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,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,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,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 };   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,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AuthCodeVIEwpackage 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

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