Android的登陆界面生成验证码

简单的实现，可以把这个当做一个工具类直接使用

package cn.com.lhy;

import java.util.Random;

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

public class BPUtil {
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 BPUtil bputil;
public static BPUtil getinstance(){
if(bputil==null){
bputil=new BPUtil();
}
return bputil;
}
private static final int DEFAULT_CODE_LENGTH = 4;//默认验证码的长度
private static final int DEFAULT_FONT_SIZE = 30;//默认字体大小
private static final int DEFAULT_LINE_NUMBER = 6;//默认线的数量
private static final int BASE_PADDING_LEFT = 10, //左边距
RANGE_PADDING_LEFT = 20,//左边距范围值
BASE_PADDING_TOP = 15, //上边距
RANGE_PADDING_TOP = 20; //上边距范围值
private static final int DEFAULT_WIDTH = 120,//默认宽度，图片的总宽度
DEFAULT_HEIGHT = 50;//默认宽、高
private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT;
private int base_padding_left = BASE_PADDING_LEFT,
range_padding_left = RANGE_PADDING_LEFT,
base_padding_top = BASE_PADDING_TOP,
range_padding_top = RANGE_PADDING_TOP;
private int codeLength = DEFAULT_CODE_LENGTH,
line_number = DEFAULT_LINE_NUMBER,
font_size = DEFAULT_FONT_SIZE;
private String code;
private int padding_left, padding_top;
private Random random = new Random(); //生成一个可以产生随机变量的对象
public Bitmap createBitmap() { //创建bitmap
padding_left = 0;

Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888);
Canvas c = new Canvas(bp);

code = createCode();

c.drawColor(Color.WHITE);
Paint paint = new Paint();
paint.setTextSize(font_size); //设置字体大小

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() { //从登陆界面是获得生成的验证码的数字，返回的是字符型
return code;
}
//生成随机数
private String createCode() {
StringBuilder buffer = new StringBuilder();
for (int i = 0; i < codeLength; i++) {
buffer.append(CHARS[random.nextInt(CHARS.length)]); //利用数组站对应的位置来随机生成
//StringBuilder将文本或对象的字符串表示形式添加到由当前 StringBuilder 对象表示的字符串的结尾处。
}
return buffer.toString(); //返回时将buffer转换成string类型
}
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); //设置线宽
paint.setColor(color); //给字体附加颜色
canvas.drawLine(startX, startY, stopX, stopY, paint); //画图开始的位置
}
private int randomColor() {
return randomColor(1);
}
//随机生成的颜色
private int randomColor(int rate) { //这里面用到的颜色是根据这个红绿色蓝色
int red = random.nextInt(256) / rate; //通过随机生成的0-255之间的数字，这些数字再通过16进制转化，例如红色#ff0000就是是红色255，蓝色绿色0000
int green = random.nextInt(256) / rate; //刚好rate传的是一个1，就是16进制的
int blue = random.nextInt(256) / rate;
return Color.rgb(red, green, blue);
}
private void randomTextStyle(Paint paint) {
int color = randomColor(); //颜色随机生成 颜色
paint.setColor(color); //对字体设置生成的颜色
paint.setFakeBoldText(random.nextBoolean()); //true为粗体，false为非粗体
float skewX = random.nextInt(11) / 10;
skewX = random.nextBoolean() ? skewX : -skewX; //三目运算符如果random随机生成为true的话就是skeyX，否则-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);
}
}
在主的activity中
imageview.setImageBitmap(BPUtil.getinstance().createBitmap());//这里得先就给它设置一个
imageview.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
imageview.setImageBitmap(BPUtil.getinstance().createBitmap());
et.setText("");
}
});
login.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
String code = et.getText().toString().trim();
Toast.makeText(LoginActivity.this, code, 500).show();
if(code.equals(BPUtil.getinstance().getCode())){
Toast.makeText(LoginActivity.this, "恭喜，验证通过", 500).show();
Intent intent = new Intent(LoginActivity.this,Welcome_Activity.class);
startActivity(intent);
}else{
Toast.makeText(LoginActivity.this, "对不起，验证失败", 500).show();
}

}
});