android - VerticalSeekBar 和事件

Question

这是我的 VerticalSeeker 类:

public class VerticalSeekBar extends SeekBar implements SeekBar.OnSeekBarChangeListener{

    public VerticalSeekBar(Context context) {
        super(context);
        this.setOnSeekBarChangeListener(this);
    }

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

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

    public void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(h, w, oldh, oldw);
    }

    @Override
    protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(heightMeasureSpec, widthMeasureSpec);
        setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth());
    }

    protected void onDraw(Canvas c) {
        c.rotate(-90);
        c.translate(-getHeight(), 0);

        super.onDraw(c);
    }
@Override
public boolean onTouchEvent(MotionEvent event) {
    if (!isEnabled()) {
        return false;
    }

    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
        case MotionEvent.ACTION_MOVE:
        case MotionEvent.ACTION_UP:
            setProgress((int) (getMax() * event.getY() / getHeight()) - 0);
            onSizeChanged(getWidth(), getHeight(), 0, 0);
            break;

        case MotionEvent.ACTION_CANCEL:
            break;
    }
    return true;
}

@Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
}

@Override
public void onStartTrackingTouch(SeekBar seekBar)
{
    Toast.makeText(this.getContext(), "Start", Toast.LENGTH_SHORT).show();
}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
    Toast.makeText(this.getContext(), "Stop", Toast.LENGTH_SHORT).show();
}

有人能解释一下，为什么只有“onProgressChanged”事件在触发吗？如何让“onStartTrackingTouch”和“onStopTrackingTouch”起作用？

Answer 1

至少将您的 Motion 事件 switch case 代码更改为

case MotionEvent.ACTION_UP:
  setProgress(getMax()- (int) (getMax() * event.getY() / getHeight()));
  onSizeChanged(getWidth(), getHeight(), 0, 0); 
  onChangeListener.onStopTrackingTouch(this);

在 http://hackskrieg.wordpress.com/2012/04/20/working-vertical-seekbar-for-android/ 找到了完整的实现