android - 如何在 Android 中实现验证码

Question

我想在我的应用程序中做验证码。经过初步分析，我发现他们中的大多数人都推荐使用“Simplcaptcha”。我试了一下。但我的努力是徒劳的。'simplecapcha' 的输出是一个 AWT 组件。所以它不能在Android中使用。有没有办法通过任何转换在 Android 中使用相同的方法，或者那里有任何其他好的库可用。如果是这样，任何人都可以指导我找到一个好的文档或示例。这对我会有很大的帮助。

Answer 1

您可以使用下面的自定义视图来显示captcha（根据您的需要进行调整，例如您想要 aalphanumeric captcha还是想要 a skewed captcha）

public class CaptchaView extends ImageView {

private Paint mPaint;
private static String mCaptchaAsText;

public CaptchaView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init();
}

public CaptchaView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
}

public CaptchaView(Context context) {
    super(context);
    init();
}

private void init() {
    mPaint = new Paint();
    mPaint.setColor(Color.BLACK);

    initCaptcha();
}

private static void initCaptcha() {
    mCaptchaAsText = "";
    for (int i = 0; i < 4; i++) {
        int number = (int) (Math.random() * 10);
        mCaptchaAsText += number;
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    int desiredWidth = 300;
    int desiredHeight = 80;

    int widthMode = MeasureSpec.getMode(widthMeasureSpec);
    int widthSize = MeasureSpec.getSize(widthMeasureSpec);
    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);

    int width;
    int height;

    // Measure Width
    if (widthMode == MeasureSpec.EXACTLY) {
        // Must be this size
        width = widthSize;
    } else if (widthMode == MeasureSpec.AT_MOST) {
        // Can't be bigger than...
        width = Math.min(desiredWidth, widthSize);
    } else {
        // Be whatever you want
        width = desiredWidth;
    }

    // Measure Height
    if (heightMode == MeasureSpec.EXACTLY) {
        // Must be this size
        height = heightSize;
    } else if (heightMode == MeasureSpec.AT_MOST) {
        // Can't be bigger than...
        height = Math.min(desiredHeight, heightSize);
    } else {
        // Be whatever you want
        height = desiredHeight;
    }

    // MUST CALL THIS
    setMeasuredDimension(width, height);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    mPaint.setTextSize(getMeasuredHeight());
    canvas.drawText(mCaptchaAsText,
            ((canvas.getWidth() - mPaint.measureText(mCaptchaAsText)) / 2),
            getMeasuredHeight(), mPaint);
}

public static boolean match(String value) {
    if (value.equals(mCaptchaAsText)) {
        return true;
    } else {
        if (value != null && value.length() > 0)
            initCaptcha();

        return false;
    }
}
}

Answer 2

一个非常易于使用、选项最少、适用于 Android 应用程序的设备上验证码系统REFER