Android菜鳥練習第十五課 隨機生成驗證碼及驗證碼圖片

第一部分 生成隨機驗證碼及圖片的工具類

public class CreateRandomCode {
    //    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'
//    };
    //設計隨機數的隨機範圍
    private static final char[] CHARS = {
            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

    private static CreateRandomCode bmpCode;

    public static CreateRandomCode getInstance() {
        if (bmpCode == null)
            bmpCode = new CreateRandomCode();
        return bmpCode;
    }

    //default settings
    private static final int DEFAULT_CODE_LENGTH = 4;
    private static final int DEFAULT_FONT_SIZE = 25;
    private static final int DEFAULT_LINE_NUMBER = 2;
    private static final int BASE_PADDING_LEFT = 10, RANGE_PADDING_LEFT = 15, BASE_PADDING_TOP = 15, RANGE_PADDING_TOP = 20;
    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();

    //驗證碼圖片
    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.setTextSize(font_size);

        for (int i = 0; i < code.length(); i++) {
            randomTextStyle(paint);
            randomPadding();
            c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);
        }

        for (int i = 0; i < line_number; i++) {
            drawLine(c, paint);
        }

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

    //不同樣式的驗證碼圖片
    public Bitmap createNeatBitmap() {
        padding_left = 0;

        Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888);
        Canvas c = new Canvas(bp);

        code = createCode();

        c.drawColor(Color.LTGRAY);//淺灰色畫布
        Paint paint = new Paint();
        paint.setTextSize(font_size);

        for (int i = 0; i < code.length(); i++) {
            paint.setColor(Color.BLACK);
            paint.setFakeBoldText(true);  //true爲粗體，false爲非粗體
            padding_left += base_padding_left + 8;
            padding_top = base_padding_top + 12;
            c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);
        }

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

    public String getCode() {
        return code;
    }

    //驗證碼
    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 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);
    }

    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();
        paint.setColor(color);
        paint.setFakeBoldText(random.nextBoolean());  //true爲粗體，false爲非粗體
        float skewX = random.nextInt(11) / 10;
        skewX = random.nextBoolean() ? skewX : -skewX;
        paint.setTextSkewX(skewX); //float類型參數，負數表示右斜，整數左斜
//      paint.setUnderlineText(true); //true爲下劃線，false爲非下劃線
//      paint.setStrikeThruText(true); //true爲刪除線，false爲非刪除線
    }

    private void randomPadding() {
        padding_left += base_padding_left + random.nextInt(range_padding_left);
        padding_top = base_padding_top + random.nextInt(range_padding_top);
    }
}  

第二部分 Activity部分

public class MainActivity extends AppCompatActivity {
    public ImageView mIvCode;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mIvCode = (ImageView) findViewById(R.id.iv_code);
        mIvCode.setImageBitmap(CreateRandomCode.getInstance().createNeatBitmap());
        Toast.makeText(MainActivity.this,CreateRandomCode.getInstance().getCode(),Toast.LENGTH_SHORT).show();
        mIvCode.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mIvCode.setImageBitmap(CreateRandomCode.getInstance().createNeatBitmap());
                Toast.makeText(MainActivity.this,CreateRandomCode.getInstance().getCode(),Toast.LENGTH_SHORT).show();
            }
        });
    }
}

第三部分 佈局部分

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/iv_code"
        android:layout_width="100dp"
        android:layout_height="45dp"
        android:background="#f3f3f3" />
</RelativeLayout>