android – 自定义ProgressBar

class ProgressDrawable extends Drawable {
    private static final int nUM_RECTS = 10;
    Paint mPaint = new Paint();

    @Override
    protected Boolean onLevelChange(int level) {
        invalidateSelf();
        return true;
    }

    @Override
    public void draw(Canvas canvas) {
        int level = getLevel();
        Rect b = getBounds();
        float width = b.width();
        for (int i = 0; i < NUM_RECTS; i++) {
            float left = width * i / NUM_RECTS;
            float right = left + 0.9f * width / NUM_RECTS;
            mPaint.setColor((i + 1) * 10000 / NUM_RECTS <= level? 0xff888888 : 0xffbbbbbb);
            canvas.drawRect(left,b.top,right,b.bottom,mPaint);
        }
    }

    @Override
    public void setAlpha(int alpha) {
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSLUCENT;
    }
}

并在onCreate中使用以下内容进行测试：

LinearLayout ll = new LinearLayout(this);
ll.setOrientation(LinearLayout.VERTICAL);

final ProgressBar pb = new ProgressBar(this,null,android.R.attr.progressBarStyleHorizontal);
Drawable d = new ProgressDrawable();
pb.setProgressDrawable(d);
pb.setPadding(20,20,0);
ll.addView(pb);

OnSeekBarchangelistener l = new OnSeekBarchangelistener() {
    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
    }

    @Override
    public void onProgressChanged(SeekBar seekBar,int progress,Boolean fromUser) {
        int newProgress = pb.getMax() * progress / seekBar.getMax();
        Log.d(tag,"onProgressChanged " + newProgress);
        pb.setProgress(newProgress);
    }
};

int[] maxs = {4,10,60,110};
for (int i = 0; i < maxs.length; i++) {
    SeekBar sb = new SeekBar(this);
    sb.setMax(maxs[i]);
    sb.setOnSeekBarchangelistener(l);
    sb.setPadding(20,0);
    ll.addView(sb);
}

setContentView(ll);