效果图：
关键代码：
package com.textcode;
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 TextImage {
private static TextImage bmpCode;
public static TextImage getInstance() {
if (bmpCode == null)
bmpCode = new TextImage();
return bmpCode;
}
private TextImage(){
}
// default settings
private static final int DEFAULT_FONT_SIZE = 25;
private static final int DEFAULT_LINE_NUMBER = 2;
private static final int BASE_PADDING_LEFT = 5, RANGE_PADDING_LEFT = 25, BASE_PADDING_TOP = 15, RANGE_PADDING_TOP = 30;
private static final int DEFAULT_WIDTH = 40, DEFAULT_HEIGHT = 60;
// settings decided by the layout xml
// canvas width and height
private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT;
// random word space and pading_top
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;
// number of chars, lines; font size
private int line_number = DEFAULT_LINE_NUMBER, font_size = DEFAULT_FONT_SIZE;
// variables
private int padding_left, padding_top;
private Random random = new Random();
// 验证码图片
public Bitmap createBitmap(String text) {
padding_left=0;
width=DEFAULT_WIDTH*text.length();
Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888);
Canvas c = new Canvas(bp);
c.drawColor(Color.argb(100,240,248,255));
Paint paint = new Paint();
paint.setTextSize(font_size);
for (int i = 0; i < text.length(); i++) {
randomTextStyle(paint);
randomPadding();
c.drawText(String.valueOf(text.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;
}
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) + 10;
padding_top = base_padding_top + random.nextInt(range_padding_top);
}
}
详细项目代码：