（五十一）生成图片验证码的代码如下所示

1、程序的结构如下所示：

2、LoginImageViewCode.java的代码如下所示

package com.app.code;
import java.util.Random;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;

public class LoginImageViewCode {

    private static Context context;

    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 LoginImageViewCode bpUtil;

    private LoginImageViewCode(Context context) {
        this.context = context;
    };

    public static LoginImageViewCode getInstance(Context context) {
        if (bpUtil == null)
            bpUtil = new LoginImageViewCode(context);
        return bpUtil;
    }

    // default settings
    private static final int DEFAULT_CODE_LENGTH = 4;// 验证码的长度 这里是4位
    private static final int DEFAULT_FONT_SIZE = 60;// 字体大小
    private static final int DEFAULT_LINE_NUMBER = 4;// 多少条干扰线
    private static final int BASE_PADDING_LEFT = 20; // 左边距
    private static final int RANGE_PADDING_LEFT = 15;// 左边距范围值
    private static final int BASE_PADDING_TOP = 42;// 上边距
    private static final int RANGE_PADDING_TOP = 28;// 上边距范围值
    private static final int DEFAULT_WIDTH = 210;// 默认宽度.图片的总宽
    private static final int DEFAULT_HEIGHT = 92;// 默认高度.图片的总高

    private static final int DEFAULT_POINT_NUMBER = 20;
    private final int DEFAULT_COLOR = 0xff;// 默认背景颜色值

    // settings decided by the layout xml
    // canvas width and height

    private int width = DEFAULT_WIDTH;
    private int height = DEFAULT_HEIGHT;

    // random word space and pading_top
    private int base_padding_left = BASE_PADDING_LEFT;
    private int range_padding_left = RANGE_PADDING_LEFT;
    private int base_padding_top = BASE_PADDING_TOP;
    private int range_padding_top = RANGE_PADDING_TOP;

    // number of chars, lines; font size
    private int codeLength = DEFAULT_CODE_LENGTH;
    private int line_number = DEFAULT_LINE_NUMBER;
    private int point_number = DEFAULT_POINT_NUMBER;
    private int font_size = DEFAULT_FONT_SIZE;

    // variables
    private String code;// 保存生成的验证码
    private int padding_left, padding_top;
    private Random random = new Random();

    private Bitmap createBitmap() {
        padding_left = 0;
        // 产生一个相同大小的画布
        Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888);
        Canvas c = new Canvas(bp);

        code = createCode();

        Paint paint = new Paint();

        for (int i = 0; i < code.length(); i++) {
            paint.setTextSize(font_size);
            randomTextStyle(paint);
            randomPadding();
            c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);// 以（padding_left,padding_top）为原点，使用画笔绘制文本code.charAt(i)
                                                                                // //
                                                                                // +
                                                                                // ""
        }
        int redColor = context.getResources().getColor(
                R.color.login_promt_text_red); // 设置线条的颜色为红色
        for (int i = 0; i < line_number; i++) {
            drawLine(c, paint, redColor);
        }

        for (int i = 0; i < point_number; i++) {
            drawPoint(c, paint);
        }

        c.save(Canvas.ALL_SAVE_FLAG);// 保存
        c.restore();//
        return bp;
    }

    public String getCode() {
        return code.toLowerCase();
    }

    public Bitmap getBitmap() {
        return createBitmap();
    }

    private String createCode() {
        StringBuilder buffer = new StringBuilder();
        for (int i = 0; i < codeLength; i++) {
            buffer.append(CHARS[random.nextInt(CHARS.length)]);
        }
        return buffer.toString();
    }

    private void drawPoint(Canvas canvas, Paint paint) {

        int color = context.getResources().getColor(R.color.login_text_gray); // 设置字体的颜色为红色
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        paint.setStrokeWidth(3);
        paint.setColor(color);
        canvas.drawPoint(x, y, paint);
    }

    private void drawLine(Canvas canvas, Paint paint, int color) {
        // int color = randomColor();

        int startX = random.nextInt(width);
        int startY = random.nextInt(height);
        int stopX = random.nextInt(width);
        int stopY = random.nextInt(height);
//        int startX = (Math.abs(random.nextInt(width)))%(width+1)+width;
//        int startY = (Math.abs(random.nextInt(height)))%(height+1)+height;
//        int startX = 0;
//        int startY = random.nextInt(height);
//        int stopX = (Math.abs(random.nextInt(width)))%(width+1)+width;
//        int stopY = (Math.abs(random.nextInt(height)))%(height+1)+height;
        paint.setStrokeWidth(3);
        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();
        int color = context.getResources().getColor(
                R.color.login_promt_text_red); // 设置字体的颜色为红色
        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);
        padding_top = base_padding_top + random.nextInt(range_padding_top);
    }
}

2、MainActivity.java的代码如下所示

package com.app.code;


import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
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 {
    
    ImageView vc_image;
    Button vc_shuaixi,vc_ok;
    String getCode=null;
    EditText vc_code;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        vc_image=(ImageView)findViewById(R.id.vc_image);
        vc_image.setImageBitmap(LoginImageViewCode.getInstance(MainActivity.this).getBitmap());
        vc_code=(EditText) findViewById(R.id.vc_code);
        
        getCode=LoginImageViewCode.getInstance(MainActivity.this).getCode(); //获取显示的验证码
        Log.e("info", getCode+"----");
        vc_shuaixi=(Button)findViewById(R.id.vc_shuaixi);
        vc_shuaixi.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                vc_image.setImageBitmap(LoginImageViewCode.getInstance(MainActivity.this).getBitmap());
                getCode=LoginImageViewCode.getInstance(MainActivity.this).getCode();
            }
        });
        
        vc_ok=(Button)findViewById(R.id.vc_ok);
        vc_ok.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
            String    v_code=vc_code.getText().toString().trim();
            if(v_code==null||v_code.equals("")){
                Toast.makeText(MainActivity.this, "没有填写验证码", 2).show();
            }else if(!v_code.equals(getCode)){
                Toast.makeText(MainActivity.this, "验证码填写不正确", 2).show();
            }else{
                Toast.makeText(MainActivity.this, "操作成功", 2).show();
            }
            
            }
        });
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

3、activity_main.xml的代码如下所示

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <LinearLayout
        android:id="@+id/yh"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="用户名:" />

        <EditText
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/pwd"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/yh"
        android:orientation="horizontal" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密码:" />

        <EditText
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/code"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/pwd"
        android:layout_marginTop="4dp"
        android:gravity="center_vertical"
        android:orientation="horizontal" >

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="5dp"
            android:orientation="horizontal" >

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="20dp"
                android:layout_marginRight="5dp"
                android:text="验 证 码:"
                android:textColor="#000000" />

            <EditText
                android:id="@+id/vc_code"
                android:layout_width="60dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:background="#0000"
                android:maxLength="4"
                android:paddingBottom="10dp"
                android:paddingLeft="10dp"
                android:paddingTop="10dp"
                android:textColor="#000000"
                android:textSize="14sp" />
        </LinearLayout>

        <ImageView
            android:id="@+id/vc_image"
            android:layout_width="600dp"
            android:layout_height="600dp"
            android:layout_marginBottom="10dp"
            android:layout_marginTop="5dp"
            android:layout_weight="1" />

        <Button
            android:id="@+id/vc_shuaixi"
            android:layout_width="40dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:layout_marginBottom="10dp"
            android:layout_marginLeft="5dp"
            android:layout_marginRight="5dp"
            android:layout_marginTop="5dp"
            android:background="@android:color/transparent"
            android:text="刷新验证码"
            android:textColor="#7f7f7f"
            android:textSize="12sp"
            android:textStyle="italic" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/code"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/vc_ok"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="确定" />
    </LinearLayout>

</RelativeLayout>

4、color.xml的代码如下所示

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <color name="login_promt_text_red">#eb271c</color>
    <color name="login_text_gray">#a8a8a8</color>

</resources>