android 随机生成4位的二维码

步骤一：

activity_main:

<?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"  
            android:background="@android:color/white" >  
            <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:textColor="@android:color/darker_gray"  
                android:textSize="20sp" />  
        </RelativeLayout>  
      
        <LinearLayout  
            android:layout_width="match_parent"  
            android:layout_height="40dp"  
            android:layout_marginTop="30dp"  
            android:orientation="vertical"   
            android:layout_marginLeft="15dp"  
            android:layout_marginRight="15dp"  
            android:background="@color/color_blue">  
      
              
      
            <LinearLayout  
                android:layout_width="match_parent"  
                android:layout_height="match_parent"  
                android:gravity="center_vertical"  
                android:orientation="horizontal" >  
      
                <TextView  
                    android:layout_width="wrap_content"  
                    android:layout_height="wrap_content"  
                    android:layout_marginLeft="20dp"  
                    android:layout_marginRight="20dp"  
                    android:text="中国+86"  
                    android:textColor="#A2CD5A"  
                    android:textSize="16sp" />  
      
                <View  
                    android:layout_width="0.1dp"  
                    android:layout_height="match_parent"  
                    android:background="@android:color/darker_gray" />  
      
                <EditText  
                    android:id="@+id/et_forgetPass_PhoneNum"  
                    android:layout_width="match_parent"  
                    android:layout_height="wrap_content"  
                    android:layout_marginLeft="20dp"  
                    android:background="@null"  
                    android:digits="0123456789"  
                    android:hint="请填入您的手机号"  
                    android:inputType="number"  
                    android:maxLength="11"  
                    android:textSize="16sp" />  
            </LinearLayout>  
        </LinearLayout>  
      
         
      
        <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"  
                android:background="@color/white" >  
      
                <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:background="@null"  
                    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:background="@color/textcolor_select"  
            android:text="提交验证码"  
            android:textColor="@android:color/darker_gray" />  
      
    </LinearLayout> 

步骤二：

创建一个code类

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 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);  
    }  
}

步骤三：

在MainActivity中引用：

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

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;  
        }  
    }  
}