安卓开发生成图片验证码
还是以前的惯例,先入为主发上效果图:
可以看到,验证码错误的时候,验证码也会随着刷新一次,缺点是有的时候生成的验证码会连人都辨别不出来,思路如下:
1.画干扰线 drawLine(float startX,float startY,float stopX,float stopY,Paint paint);
2.画字 drawText(String text,int start,int end,Paint paint);
3.画图 drawBitmap(Bitmap bitmap,float left,float top,Paint paint);
4.setTextSkewX(flaot) //负数代表右斜,整数左斜
5.Color.rgb(red,green,blue);根据三原色生成颜色
6.验证码都是又若干个干扰线,四个固定长度的随机字符,随机的颜色,随机的倾斜度,随机的padding组成,这样一来是不是就思路就清晰很多了。
因为代码比较多,所以单独写了一个Code工具类,工具类代码如下:
package com.example.administrator.image;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import java.util.Random;
public class Code {
//随机数数组
private static final char[] CHARS = {
'1','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
//padding值
private static final int DEFAULT_LINE_NUMBER = 10;
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;
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();
//验证码图片
public Bitmap createBitmap() {
padding_left = 0;
Bitmap bp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bp);
code = createCode();
c.drawColor(Color.WHITE);
Paint paint = new Paint();
paint.setAntiAlias(true);//是否抗锯齿
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
}
//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);
}
}
MainActivity代码如下:
package com.example.administrator.image;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
public class MainActivity extends Activity implements View.OnClickListener {
public static final String TAG = MainActivity.class.getName();
private ImageView iv_showCode;
private EditText et_phoneCode;
//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();
if (phoneCode.equals(realCode)) {
Toast.makeText(MainActivity.this, "验证码正确", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(MainActivity.this, "验证码错误", Toast.LENGTH_SHORT).show();
iv_showCode.setImageBitmap(Code.getInstance().createBitmap());
realCode = Code.getInstance().getCode().toLowerCase();
Log.v(TAG,"realCode"+realCode);
}
break;
}
}
}
xml布局文件代码如下:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp"
>
<TextView
android:id="@+id/tv_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="找回密码"
android:textSize="20sp" />
</RelativeLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:layout_marginTop="20dp"
android:orientation="horizontal" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="40dp"
>
<EditText
android:id="@+id/et_phoneCodes"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:hint="请输入右侧验证码" />
</LinearLayout>
<ImageView
android:id="@+id/iv_showCode"
android:layout_width="100dp"
android:layout_marginLeft="10dp"
android:layout_height="match_parent" />
</LinearLayout>
<Button
android:id="@+id/but_forgetpass_toSetCodes"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:text="提交验证码"
/>
</LinearLayout>