androdi 数字验证码

本来是在写着自定义view,写着写着又向其中添加了点击刷新内容，所以就觉得这很像是一个数字验证码的功能。点击可以随机变换view上的数字，其中，我又增加了干扰线，与干扰点。
效果如下：

流程如下：
一，在资源目录values下新建attrs.xml文档

    <!--随机4位验证码-->
    <attr name="txtContent" format="string" />
    <attr name="txtColor" format="color" />
    <attr name="txtBackgroundColor" format="color" />
    <attr name="txtSize" format="dimension" />
    <declare-styleable name="txtView">
        <attr name="txtContent" />
        <attr name="txtColor" />
        <attr name="txtBackgroundColor" />
        <attr name="txtSize" />
    </declare-styleable>

二，接下来就是在view的构造方法中获得我们自定义的属性，重写onDraw就ok了，在这例子，涉及到view在布局文件中设置WRAP_CONTENT或 MATCH_PARENT，系统帮我们测量的结果就是MATCH_PARENT的长度。所以，当设置了WRAP_CONTENT时，我们需要自己进行测量，即重写onMesure方法”。

  public TxtView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray array = context.getTheme().obtainStyledAttributes(attrs,
                R.styleable.txtView, defStyleAttr, 0);
        int num = array.length();
        for (int i = 0; i < num; i++) {
            int attr = array.getIndex(i);
            switch (attr) {
                case R.styleable.txtView_txtContent:
                    mTxtText = array.getString(attr);
                    break;
                case R.styleable.txtView_txtColor:
                    mTxtColor = array.getColor(attr, Color.BLACK);
                    break;
                case R.styleable.txtView_txtBackgroundColor:
                    mTxtBackgroundColor = array.getColor(attr, Color.YELLOW);
                    break;
                case R.styleable.txtView_txtSize:
                    mTxtSize = array.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(
                            TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()
                    ));
                    break;
            }
        }
        array.recycle();

        mPaint = new Paint();
        mPaint.setTextSize(mTxtSize);
        mBound = new Rect();
        mPaint.getTextBounds(mTxtText, 0, mTxtText.length(), mBound);

        this.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                mTxtText = randomText();
                postInvalidate();
            }
        });
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int width, height;
        if (widthMode == MeasureSpec.EXACTLY) {
            width = widthSize;
        } else {
            mPaint.setTextSize(mTxtSize);
            mPaint.getTextBounds(mTxtText, 0, mTxtText.length(), mBound);
            float textWidth = mBound.width();
            int desired = (int) (getPaddingLeft() + textWidth + getPaddingRight());
            width = desired;
        }

        if (heightMode == MeasureSpec.EXACTLY) {
            height = heightSize;
        } else {
            mPaint.setTextSize(mTxtSize);
            mPaint.getTextBounds(mTxtText, 0, mTxtText.length(), mBound);
            float textHeight = mBound.height();
            int desired = (int) (getPaddingTop() + textHeight + getPaddingBottom());
            height = desired;
        }

        setMeasuredDimension(width, height);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        mPaint.setColor(mTxtBackgroundColor);
        canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint);


        mPaint.setAntiAlias(true);
        mPaint.setTextSize(mTxtSize);
        randomTextStyle(mPaint);
        canvas.drawText(mTxtText, getWidth() / 2 - mBound.width() / 2, getHeight() / 2 + mBound.height() / 2,
                mPaint);

        for (int i = 0; i<4;i++){
            drawLine(canvas,mPaint);
        }

        mPaint.setColor(randomColor());
        for (int i = 0; i < 50; i++) {
            drawPoint(canvas, mPaint);
        }
    }

至此，我们的一个获取4位随机验证就完成了。如果想要获取验证码的可以，通过getCode() 这个方法获取得到。

详细代码下载
http://download.csdn.net/detail/u013318697/9850127