验证码颜色、字母、数字、线条、圆点、位置都随机，点击切换验证码

才刚刚开始写这种自定义控件，但是发现验证码完全可以不用自定义控件，自定义控件好像麻烦点，下面就来介绍了使用bitmap的形式显示验证码

这个起初我也不会，都是看大神们弄的， 我也就添了点东西，让验证码更多样，哈哈，废话不多说，上交代码了

第一步 ，创建一个类

public class CodeBitmap {


    //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'
    };
    //padding值
    private static final int BASE_PADDING_LEFT = 10, RANGE_PADDING_LEFT = 15, BASE_PADDING_TOP = 30, RANGE_PADDING_TOP = 20;
    //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;
    private Random random = new Random();
    private String returncode;
    private int painsize=40;
//线条数
    int line_number=5;
    private int padding_left, padding_top;
    private static CodeBitmap bmpCode;
    public static CodeBitmap getInstance() {
        if(bmpCode == null)
            bmpCode = new CodeBitmap();
        return bmpCode;
    }
    //验证码图片
    public Bitmap cratebitmap(int width,int height) {
        padding_left = 0;
        Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        //创建验证码
        returncode = crateCode();
        canvas.drawColor(Color.WHITE);

        Paint paint=new Paint();
        paint.setAntiAlias(true);
        paint.setTextSize(painsize);

        //画验证码
        for (int i=0;i<returncode.length();i++) {
            randomTextStyle(paint);
            randomPadding();
            canvas.drawText(returncode.charAt(i) + "", padding_left, padding_top, paint);
        }
        //画线条
        for (int i = 0; i < line_number; i++) {
            drawLine(canvas, paint,width,height);
        }

        //画小圆点
        for (int i=0;i<20;i++){
           drawpoint(canvas,paint,width,height);
        }
        canvas.save( Canvas.ALL_SAVE_FLAG );//保存
        canvas.restore();//
        return bitmap;
    }

    //画干扰线
    private void drawLine(Canvas canvas, Paint paint,int width,int height) {
        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);
    }
    //画圆dian
    private void drawpoint(Canvas canvas, Paint paint,int width,int height){
        int color = randomColor();
        paint.setStrokeWidth(1);
        paint.setColor(color);
        int[] rang=getPoint(height,width);
        canvas.drawCircle(rang[0], rang[1],random.nextInt(5),paint);
    }
    // 随机产生点的圆心点坐标
    public static int[] getPoint(int height, int width) {
        int[] tempCheckNum = { 0, 0, 0, 0 };
        tempCheckNum[0] = (int) (Math.random() * width);
        tempCheckNum[1] = (int) (Math.random() * height);
        return tempCheckNum;
    }
    //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);
    }
    //生成验证码
    private String crateCode() {
        StringBuffer returnbf = new StringBuffer();
        for (int i = 0; i < 4; i++) {
            returnbf.append(CHARS[random.nextInt(CHARS.length)]);
        }
        return returnbf.toString();
    }

    //获取验证码的值
    public String getcode(){
        return returncode;
    }
}

第二步，调取类中cratebitmap的方法，显示图片就可以啦

先看mainactivity布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <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:background="@null"
                android:hint="请输入右侧验证码" />
        </LinearLayout>

        <ImageView
            android:id="@+id/iv_showCode"
            android:layout_width="120dp"
            android:layout_marginLeft="10dp"
            android:layout_height="60dp" />

    </LinearLayout>

    <Button
        android:id="@+id/but_forgetpass_toSetCodes"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:text="验        证"
      />

</LinearLayout>

再看看mainActivity

public class MainActivity extends AppCompatActivity {

    private Button button;
    private EditText dode;
    private ImageView iv_showCode;
    private String realcode;
    //设置图片大小
    private static final int DEFAULT_WIDTH = 120, DEFAULT_HEIGHT = 60;
    private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initview();
    }
    private void initview(){
        button = (Button) findViewById(R.id.but_forgetpass_toSetCodes);
        dode = (EditText)findViewById(R.id.et_phoneCodes);
        iv_showCode = (ImageView)findViewById(R.id.iv_showCode);
        iv_showCode.setImageBitmap(CodeBitmap.getInstance().cratebitmap(width,height));
        realcode = CodeBitmap.getInstance().getcode().toLowerCase();
        iv_showCode.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                iv_showCode.setImageBitmap(CodeBitmap.getInstance().cratebitmap(width,height));
                realcode = CodeBitmap.getInstance().getcode().toLowerCase();
            }
        });
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String editcode=dode.getText().toString().trim();
                if (editcode.equals(realcode)){
                    Toast.makeText(MainActivity.this,"验证码输入正确！",Toast.LENGTH_SHORT).show();
                }else {
                    Toast.makeText(MainActivity.this,"验证码错误，请重新输入！",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}