Android随机生成验证码,Android利用随机数绘制不规则的验证码，加强用户登录或者注册的安全性。
具体思路如下：
在一块固定宽高的画布上，画上固定个数的随机数字和字母，再画上固定条数的干扰线
随机数和干扰线的颜色随机生成，随机数的样式随机生成。
界面效果如下：
1、生成随机数代码，Code.java:
public class Code {
//随机数数组
private static final char[] CHARS = {
'2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm',
'n', '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', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
};
private static Code bmpCode;
public static Code getInstance() {
if(bmpCode == null)
bmpCode = new Code();
return bmpCode;
}
//default settings
//验证码默认随机数的个数
private static final int DEFAULT_CODE_LENGTH = 4;
//默认字体大小
private static final int DEFAULT_FONT_SIZE = 25;
//默认线条的条数
private static final int DEFAULT_LINE_NUMBER = 5;
//padding值
private static final int base_PADDING_LEFT = 10, RANGE_PADDING_LEFT = 15, base_PADDING_TOP = 15, RANGE_PADDING_TOP = 20;
//验证码的默认宽高
private static final int DEFAULT_WIDTH = 100, DEFAULT_HEIGHT = 40;
//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 codeLength = DEFAULT_CODE_LENGTH, line_number = DEFAULT_LINE_NUMBER, font_size = DEFAULT_FONT_SIZE;
//variables
private String code;
private int padding_left, padding_top;
private Random random = new Random();
//验证码图片
public Bitmap createBitmap() {
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.setAntiAlias(true);
paint.setTextSize(font_size);
//画验证码
for (int i = 0; i < code.length(); i++) {
randomTextStyle(paint);
randomPadding();
c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);
}
//画线条
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;
}
//生成验证码
private String createCode() {
StringBuilder buffer = new StringBuilder();
for (int i = 0; i < codeLength; i++) {
buffer.append(CHARS[random.nextInt(CHARS.length)]);
}
return buffer.toString();
}
//画干扰线
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);
}
//生成随机颜色
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);
}
//随机生成文字样式，颜色，粗细，倾斜度
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
}
//随机生成padding值
private void randomPadding() {
padding_left += base_padding_left + random.nextInt(range_padding_left);
padding_top = base_padding_top + random.nextInt(range_padding_top);
}
}
2、编写布局文件，activity_main.xml:
3、在主界面生成随机数，校验验证码MainActivity.java:
public class MainActivity extends Activity implements onClickListener {
public static final String TAG = MainActivity.class.getName();
private ImageView iv_showCode;
private EditText et_phoneCode;
private EditText et_phoneNum;
//产生的验证码
private String realCode;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_phoneCode = (EditText) findViewById(R.id.et_phoneCodes);
Button but_toSetCode = (Button) findViewById(R.id.but_forgetpass_toSetCodes);
but_toSetCode.setonClickListener(this);
iv_showCode = (ImageView) findViewById(R.id.iv_showCode);
//将验证码用图片的形式显示出来
iv_showCode.setImageBitmap(Code.getInstance().createBitmap());
realCode = Code.getInstance().getCode().toLowerCase();
iv_showCode.setonClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.iv_showCode:
iv_showCode.setImageBitmap(Code.getInstance().createBitmap());
realCode = Code.getInstance().getCode().toLowerCase();
Log.v(TAG,"realCode"+realCode);
break;
case R.id.but_forgetpass_toSetCodes:
String phoneCode = et_phoneCode.getText().toString().toLowerCase();
String msg = "生成的验证码："+realCode+"输入的验证码:"+phoneCode;
Toast.makeText(MainActivity.this,msg,Toast.LENGTH_LONG).show();
if (phoneCode.equals(realCode)) {
Toast.makeText(MainActivity.this, phoneCode + "验证码正确", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(MainActivity.this, phoneCode + "验证码错误", Toast.LENGTH_SHORT).show();
}
break;
}
}
}
至此，基本功能已实现，源码下载：http://xiazai.jb51.net/201611/yuanma/AndroidSecurityCode(jb51.net).rar
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。
