Android 获取随机验证码功能示例

验证码功能在各大网站都能用到，下面小编通过实例代码给大家分享android 获取随机验证码功能，具体代码如下所示：

 package cn.hk.image; 
import java.awt.basicstroke; 
import java.awt.color; 
import java.awt.font; 
import java.awt.graphics2d; 
import java.awt.image.bufferedimage; 
import java.io.ioexception; 
import java.io.outputstream; 
import java.util.random; 
import javax.imageio.imageio; 
public class verifycode { 
  private int w = 70; 
  private int h = 35; 
  private random r = new random(); 
  // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_gb2312"} 
  private string[] fontnames = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_gb2312"}; 
  // 可选字符 
  private string codes = "23456789abcdefghjkmnopqrstuvwxyzabcdefghjkmnpqrstuvwxyz"; 
  // 背景色 
  private color bgcolor = new color(255, 255, 255); 
  // 验证码上的文本 
  private string text ; 
  // 生成随机的颜色 
  private color randomcolor () { 
    int red = r.nextint(150); 
    int green = r.nextint(150); 
    int blue = r.nextint(150); 
    return new color(red, green, blue); 
  } 
  // 生成随机的字体 
  private font randomfont () { 
    int index = r.nextint(fontnames.length); 
    string fontname = fontnames[index];//生成随机的字体名称 
    int style = r.nextint(4);//生成随机的样式, 0(无样式), 1(粗体), 2(斜体), 3(粗体+斜体) 
    int size = r.nextint(5) + 24; //生成随机字号, 24 ~ 28 
    return new font(fontname, style, size); 
  } 
  // 画干扰线 
  private void drawline (bufferedimage image) { 
    int num = 3;//一共画3条 
    graphics2d g2 = (graphics2d)image.getgraphics(); 
    for(int i = 0; i < num; i++) {//生成两个点的坐标，即4个值 
      int x1 = r.nextint(w); 
      int y1 = r.nextint(h); 
      int x2 = r.nextint(w); 
      int y2 = r.nextint(h);  
      g2.setstroke(new basicstroke(1.5f));  
      g2.setcolor(color.blue); //干扰线是蓝色 
      g2.drawline(x1, y1, x2, y2);//画线 
    } 
  } 
  // 随机生成一个字符 
  private char randomchar () { 
    int index = r.nextint(codes.length()); 
    return codes.charat(index); 
  } 
  // 创建bufferedimage，图片缓存区 
  private bufferedimage createimage () { 
    bufferedimage image = new bufferedimage(w, h, bufferedimage.type_int_rgb);  
    graphics2d g2 = (graphics2d)image.getgraphics();  
    g2.setcolor(this.bgcolor); 
    g2.fillrect(0, 0, w, h); 
    return image; 
  } 
  // 调用这个方法得到验证码 
  public bufferedimage getimage () { 
    bufferedimage image = createimage();//创建图片缓冲区  
    graphics2d g2 = (graphics2d)image.getgraphics();//得到绘制环境 
    stringbuilder sb = new stringbuilder();//用来装载生成的验证码文本 
    // 向图片中画4个字符 
    for(int i = 0; i < 4; i++) {//循环四次，每次生成一个字符 
      string s = randomchar() + "";//随机生成一个字母  
      sb.append(s); //把字母添加到sb中 
      float x = i * 1.0f * w / 4; //设置当前字符的x轴坐标 
      g2.setfont(randomfont()); //设置随机字体 
      g2.setcolor(randomcolor()); //设置随机颜色 
      g2.drawstring(s, x, h-5); //画图 
    } 
    this.text = sb.tostring(); //把生成的字符串赋给了this.text 
    drawline(image); //添加干扰线 
    return image;     
  } 
  // 返回验证码图片上的文本 
  public string gettext () { 
    return text; 
  } 
  // 保存图片到指定的输出流 
  public static void output (bufferedimage image, outputstream out)  
        throws ioexception { 
    imageio.write(image, "jpeg", out); 
  } 
} 

以上所述是小编给大家介绍的android 获取随机验证码功能示例，希望对大家有所帮助