Android 重写系统控件UI，自定义进度条

public class HorizontalProgressBarWithNumber extends ProgressBar
{

    private static final int DEFAULT_TEXT_SIZE = 10;
    private static final int DEFAULT_TEXT_COLOR = 0XFFFC00D1;
    private static final int DEFAULT_COLOR_UNREACHED_COLOR = 0xFFd3d6da;
    private static final int DEFAULT_HEIGHT_REACHED_PROGRESS_BAR = 2;
    private static final int DEFAULT_HEIGHT_UNREACHED_PROGRESS_BAR = 2;
    private static final int DEFAULT_SIZE_TEXT_OFFSET = 10;

    /**
     * painter of all drawing things
     */
    protected Paint mPaint = new Paint();
    /**
     * color of progress number
     */
    protected int mTextColor = DEFAULT_TEXT_COLOR;
    /**
     * size of text (sp)
     */
    protected int mTextSize = sp2px(DEFAULT_TEXT_SIZE);

    /**
     * offset of draw progress
     */
    protected int mTextOffset = dp2px(DEFAULT_SIZE_TEXT_OFFSET);

    /**
     * height of reached progress bar
     */
    protected int mReachedProgressBarHeight = dp2px(DEFAULT_HEIGHT_REACHED_PROGRESS_BAR);

    /**
     * color of reached bar
     */
    protected int mReachedBarColor = DEFAULT_TEXT_COLOR;
    /**
     * color of unreached bar
     */
    protected int mUnReachedBarColor = DEFAULT_COLOR_UNREACHED_COLOR;
    /**
     * height of unreached progress bar
     */
    protected int mUnReachedProgressBarHeight = dp2px(DEFAULT_HEIGHT_UNREACHED_PROGRESS_BAR);
    /**
     * view width except padding
     */
    protected int mRealWidth;

    protected boolean mIfDrawText = true;

    protected static final int VISIBLE = 0;

    public HorizontalProgressBarWithNumber(Context context, AttributeSet attrs)
    {
        this(context, attrs, 0);
    }

    public HorizontalProgressBarWithNumber(Context context, AttributeSet attrs,
            int defStyle)
    {
        super(context, attrs, defStyle);
        obtainStyledAttributes(attrs);
        mPaint.setTextSize(mTextSize);
        mPaint.setColor(mTextColor);
    }

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

        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = measureHeight(heightMeasureSpec);
        setMeasuredDimension(width, height);

        mRealWidth = getMeasuredWidth() - getPaddingRight() - getPaddingLeft();
    }

    private int measureHeight(int measureSpec)
    {
        int result = 0;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);
        if (specMode == MeasureSpec.EXACTLY)
        {
            result = specSize;
        } else
        {
            float textHeight = (mPaint.descent() - mPaint.ascent());
            result = (int) (getPaddingTop() + getPaddingBottom() + Math.max(
                    Math.max(mReachedProgressBarHeight,
                            mUnReachedProgressBarHeight), Math.abs(textHeight)));
            if (specMode == MeasureSpec.AT_MOST)
            {
                result = Math.min(result, specSize);
            }
        }
        return result;
    }

    /**
     * get the styled attributes
     * 
     * @param attrs
     */
    private void obtainStyledAttributes(AttributeSet attrs)
    {
        // init values from custom attributes
        final TypedArray attributes = getContext().obtainStyledAttributes(
                attrs, R.styleable.HorizontalProgressBarWithNumber);

        mTextColor = attributes
                .getColor(
                        R.styleable.HorizontalProgressBarWithNumber_progress_text_color,
                        DEFAULT_TEXT_COLOR);
        mTextSize = (int) attributes.getDimension(
                R.styleable.HorizontalProgressBarWithNumber_progress_text_size,
                mTextSize);

        mReachedBarColor = attributes
                .getColor(
                        R.styleable.HorizontalProgressBarWithNumber_progress_reached_color,
                        mTextColor);
        mUnReachedBarColor = attributes
                .getColor(
                        R.styleable.HorizontalProgressBarWithNumber_progress_unreached_color,
                        DEFAULT_COLOR_UNREACHED_COLOR);
        mReachedProgressBarHeight = (int) attributes
                .getDimension(
                        R.styleable.HorizontalProgressBarWithNumber_progress_reached_bar_height,
                        mReachedProgressBarHeight);
        mUnReachedProgressBarHeight = (int) attributes
                .getDimension(
                        R.styleable.HorizontalProgressBarWithNumber_progress_unreached_bar_height,
                        mUnReachedProgressBarHeight);
        mTextOffset = (int) attributes
                .getDimension(
                        R.styleable.HorizontalProgressBarWithNumber_progress_text_offset,
                        mTextOffset);

        int textVisible = attributes
                .getInt(R.styleable.HorizontalProgressBarWithNumber_progress_text_visibility,
                        VISIBLE);
        if (textVisible != VISIBLE)
        {
            mIfDrawText = false;
        }
        attributes.recycle();
    }

    @Override
    protected synchronized void onDraw(Canvas canvas)
    {

        canvas.save();
        canvas.translate(getPaddingLeft(), getHeight() / 2);

        boolean noNeedBg = false;
        float radio = getProgress() * 1.0f / getMax();
        float progressPosX = (int) (mRealWidth * radio);
        String text = getProgress() + "%";
        // mPaint.getTextBounds(text, 0, text.length(), mTextBound);

        float textWidth = mPaint.measureText(text);
        float textHeight = (mPaint.descent() + mPaint.ascent()) / 2;

        if (progressPosX + textWidth > mRealWidth)
        {
            progressPosX = mRealWidth - textWidth;
            noNeedBg = true;
        }

        // draw reached bar
        float endX = progressPosX - mTextOffset / 2;
        if (endX > 0)
        {
            mPaint.setColor(mReachedBarColor);
            mPaint.setStrokeWidth(mReachedProgressBarHeight);
            canvas.drawLine(0, 0, endX, 0, mPaint);
        }
        // draw progress bar
        // measure text bound
        if (mIfDrawText)
        {
            mPaint.setColor(mTextColor);
            canvas.drawText(text, progressPosX, -textHeight, mPaint);
        }

        // draw unreached bar
        if (!noNeedBg)
        {
            float start = progressPosX + mTextOffset / 2 + textWidth;
            mPaint.setColor(mUnReachedBarColor);
            mPaint.setStrokeWidth(mUnReachedProgressBarHeight);
            canvas.drawLine(start, 0, mRealWidth, 0, mPaint);
        }

        canvas.restore();

    }

    /**
     * dp 2 px
     * 
     * @param dpVal
     */
    protected int dp2px(int dpVal)
    {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
                dpVal, getResources().getDisplayMetrics());
    }

    /**
     * sp 2 px
     * 
     * @param spVal
     * @return
     */
    protected int sp2px(int spVal)
    {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,
                spVal, getResources().getDisplayMetrics());

    }

}

public class RoundProgressBarWidthNumber extends
        HorizontalProgressBarWithNumber
{
    /**
     * mRadius of view
     */
    private int mRadius = dp2px(30);
    private int mMaxPaintWidth;

    public RoundProgressBarWidthNumber(Context context)
    {
        this(context, null);
    }

    public RoundProgressBarWidthNumber(Context context, AttributeSet attrs)
    {
        super(context, attrs);

        mReachedProgressBarHeight = (int) (mUnReachedProgressBarHeight * 2.5f);
        TypedArray ta = context.obtainStyledAttributes(attrs,
                R.styleable.RoundProgressBarWidthNumber);
        mRadius = (int) ta.getDimension(
                R.styleable.RoundProgressBarWidthNumber_radius, mRadius);
        ta.recycle();

        mPaint.setStyle(Style.STROKE);
        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setStrokeCap(Cap.ROUND);

    }

    /**
     * 这里默认在布局中padding值要么不设置，要么全部设置
     */
    @Override
    protected synchronized void onMeasure(int widthMeasureSpec,
            int heightMeasureSpec)
    {

        mMaxPaintWidth = Math.max(mReachedProgressBarHeight,
                mUnReachedProgressBarHeight);
        int expect = mRadius * 2 + mMaxPaintWidth + getPaddingLeft()
                + getPaddingRight();
        int width = resolveSize(expect, widthMeasureSpec);
        int height = resolveSize(expect, heightMeasureSpec);
        int realWidth = Math.min(width, height);

        mRadius = (realWidth - getPaddingLeft() - getPaddingRight() - mMaxPaintWidth) / 2;

        setMeasuredDimension(realWidth, realWidth);

    }

    @Override
    protected synchronized void onDraw(Canvas canvas)
    {

        String text = getProgress() + "%";
        float textWidth = mPaint.measureText(text);
        float textHeight = (mPaint.descent() + mPaint.ascent()) / 2;

        canvas.save();
        canvas.translate(getPaddingLeft() + mMaxPaintWidth / 2, getPaddingTop()
                + mMaxPaintWidth / 2);
        mPaint.setStyle(Style.STROKE);
        // draw unreaded bar
        mPaint.setColor(mUnReachedBarColor);
        mPaint.setStrokeWidth(mUnReachedProgressBarHeight);
        canvas.drawCircle(mRadius, mRadius, mRadius, mPaint);
        // draw reached bar
        mPaint.setColor(mReachedBarColor);
        mPaint.setStrokeWidth(mReachedProgressBarHeight);
        float sweepAngle = getProgress() * 1.0f / getMax() * 360;
        canvas.drawArc(new RectF(0, 0, mRadius * 2, mRadius * 2), 0,
                sweepAngle, false, mPaint);
        // draw text
        mPaint.setStyle(Style.FILL);
        canvas.drawText(text, mRadius - textWidth / 2, mRadius - textHeight,
                mPaint);

        canvas.restore();

    }

}