android 客户端生成随机验证码的实现

首先当然是写XML咯，贴上代码

<LinearLayout 
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:orientation="horizontal"
     android:id="@+id/yh"
     >
     
     <TextView 
       android:text="用户名:"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       />
     
     <EditText 
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       />
     
   </LinearLayout>
   
   
   
   <LinearLayout 
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:orientation="horizontal"
     android:layout_below="@id/yh"
     android:id="@+id/pwd"
     >
     
     <TextView 
       android:text="密码:"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       />
     
     <EditText 
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       />
     
   </LinearLayout>

   
   <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:layout_marginTop="4dp"
        android:orientation="horizontal"
        android:layout_below="@id/pwd"
        android:id="@+id/code"
         >

        <LinearLayout
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginBottom="10dp"
          android:layout_marginLeft="10dp"
          android:layout_marginRight="10dp"
          android:layout_marginTop="5dp"
          android:orientation="horizontal" >

          <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:layout_marginRight="5dp"
            android:text="验 证 码:"
            android:textColor="#000000" />

          <EditText
            android:id="@+id/vc_code"
            android:layout_width="60dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="#0000"
            android:maxLength="4"
            android:paddingBottom="10dp"
            android:paddingLeft="10dp"
            android:paddingTop="10dp"
            android:textColor="#000000"
            android:textSize="14sp" />
        </LinearLayout>

        <ImageView
          android:id="@+id/vc_image"
          android:layout_width="wrap_content"
          android:layout_height="match_parent"
          android:layout_marginBottom="10dp"
          android:layout_marginTop="5dp"
          android:layout_weight="1" />

        <Button
          android:id="@+id/vc_shuaixi"
          android:layout_width="40dp"
          android:layout_height="wrap_content"
          android:background="@android:color/transparent"
          android:layout_gravity="center_vertical"
          android:text="刷新验证码"
          android:textStyle="italic"
          android:layout_marginTop="5dp"
          android:layout_marginBottom="10dp"
          android:layout_marginLeft="5dp"
          android:layout_marginRight="5dp"
          android:textColor="#7f7f7f"
          android:textSize="12sp" />
      </LinearLayout>
   
   <LinearLayout 
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:layout_below="@id/code"
     android:orientation="horizontal"
     >
     <Button 
       android:id="@+id/vc_ok"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:text="确定"
       />
     
   </LinearLayout>

下面贴一下MainActivity的代码:

里面的注释很详细，就不多说了！

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity {
  
  ImageView vc_image; //图标
  Button vc_shuaixi,vc_ok; //确定和刷新验证码
  String getCode=null; //获取验证码的值
  EditText vc_code; //文本框的值
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    vc_image=(ImageView)findViewById(R.id.vc_image);
    vc_image.setImageBitmap(Code.getInstance().getBitmap());
    vc_code=(EditText) findViewById(R.id.vc_code);
    
    getCode=Code.getInstance().getCode(); //获取显示的验证码
    Log.e("info", getCode+"----");
    vc_shuaixi=(Button)findViewById(R.id.vc_shuaixi);
    vc_shuaixi.setOnClickListener(new OnClickListener() {
      
      @Override
      public void onClick(View v) {
        // TODO Auto-generated method stub
        vc_image.setImageBitmap(Code.getInstance().getBitmap());
        getCode=Code.getInstance().getCode();
      }
    });
    
    vc_ok=(Button)findViewById(R.id.vc_ok);
    vc_ok.setOnClickListener(new OnClickListener() {
      
      @Override
      public void onClick(View v) {
        // TODO Auto-generated method stub
      String	v_code=vc_code.getText().toString().trim();
      if(v_code==null||v_code.equals("")){
        Toast.makeText(MainActivity.this, "没有填写验证码", 2).show();
      }else if(!v_code.equals(getCode)){
        Toast.makeText(MainActivity.this, "验证码填写不正确", 2).show();
      }else{
        Toast.makeText(MainActivity.this, "操作成功", 2).show();
      }
      
      }
    });
    
  }

最后贴一下做验证码必须的一个类Code:

import java.util.Random;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Bitmap.Config;


public class Code {

  private static final char[] CHARS = {
    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 
    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
  };
  
  private static Code bpUtil;
  private Code(){};
  public static Code getInstance() {
    if(bpUtil == null)
      bpUtil = new Code();
    return bpUtil;
  }
  //default settings
  private static final int DEFAULT_CODE_LENGTH = 4;//验证码的长度  这里是4位
  private static final int DEFAULT_FONT_SIZE = 60;//字体大小
  private static final int DEFAULT_LINE_NUMBER = 3;//多少条干扰线
  private static final int BASE_PADDING_LEFT = 20; //左边距
  private static final int RANGE_PADDING_LEFT = 35;//左边距范围值  
  private static final int BASE_PADDING_TOP = 42;//上边距
  private static final int RANGE_PADDING_TOP = 15;//上边距范围值
  private static final int DEFAULT_WIDTH = 200;//默认宽度.图片的总宽
  private static final int DEFAULT_HEIGHT = 70;//默认高度.图片的总高
  private  final int DEFAULT_COLOR=0xdf;//默认背景颜色值
  
  //settings decided by the layout xml
  //canvas width and height
  private int width = DEFAULT_WIDTH;
  private int height = DEFAULT_HEIGHT; 
  
  //random word space and pading_top
  private int base_padding_left = BASE_PADDING_LEFT;
  private int range_padding_left = RANGE_PADDING_LEFT;
  private int base_padding_top = BASE_PADDING_TOP;
  private int range_padding_top = RANGE_PADDING_TOP;
  
  //number of chars, lines; font size
  private int codeLength = DEFAULT_CODE_LENGTH;
  private int line_number = DEFAULT_LINE_NUMBER;
  private int font_size = DEFAULT_FONT_SIZE;
  
  //variables
  private String code;//保存生成的验证码
  private int padding_left, padding_top;
  private Random random = new Random();
  
  private Bitmap createBitmap() {
    padding_left = 0;
    
    Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888); 
    Canvas c = new Canvas(bp);

    code = createCode();
    
    c.drawColor(Color.rgb(DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_COLOR));
    Paint paint = new Paint();
    paint.setTextSize(font_size);
    
    for (int i = 0; i < code.length(); i++) {
      randomTextStyle(paint);
      randomPadding();
      c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);
    }

    for (int i = 0; i < line_number; i++) {
      drawLine(c, paint);
    }
    
    c.save( Canvas.ALL_SAVE_FLAG );//保存  
    c.restore();//
    return bp;
  }
  
  public String getCode() {
    return code.toLowerCase();
  }
  
  public Bitmap getBitmap(){
    return createBitmap();
  }
  private String createCode() {
    StringBuilder buffer = new StringBuilder();
    for (int i = 0; i < codeLength; i++) {
      buffer.append(CHARS[random.nextInt(CHARS.length)]);
    }
    return buffer.toString();
  }
  
  private void drawLine(Canvas canvas, Paint paint) {
    int color = randomColor();
    int startX = random.nextInt(width);
    int startY = random.nextInt(height);
    int stopX = random.nextInt(width);
    int stopY = random.nextInt(height);
    paint.setStrokeWidth(1);
    paint.setColor(color);
    canvas.drawLine(startX, startY, stopX, stopY, paint);
  }
  
  private int randomColor() {
    return randomColor(1);
  }

  private int randomColor(int rate) {
    int red = random.nextInt(256) / rate;
    int green = random.nextInt(256) / rate;
    int blue = random.nextInt(256) / rate;
    return Color.rgb(red, green, blue);
  }
  
  private void randomTextStyle(Paint paint) {
    int color = randomColor();
    paint.setColor(color);
    paint.setFakeBoldText(random.nextBoolean());  //true为粗体，false为非粗体
    float skewX = random.nextInt(11) / 10;
    skewX = random.nextBoolean() ? skewX : -skewX;
    paint.setTextSkewX(skewX); //float类型参数，负数表示右斜，整数左斜
//		paint.setUnderlineText(true); //true为下划线，false为非下划线
//		paint.setStrikeThruText(true); //true为删除线，false为非删除线
  }
  
  private void randomPadding() {
    padding_left += base_padding_left + random.nextInt(range_padding_left);
    padding_top = base_padding_top + random.nextInt(range_padding_top);
  }
}