安卓开发之自定义SeekBar竖立类（顺时针逆时针旋转90度）

最新推荐文章于 2025-04-28 11:29:15 发布

原创最新推荐文章于 2025-04-28 11:29:15 发布 · 2.2k 阅读

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本文介绍了一种自定义垂直SeekBar控件的方法，该控件通过旋转画布并调整触摸事件来实现垂直滚动效果。文中提供了详细的代码实现及如何在XML布局文件与Activity中使用的示例。

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类名：VerticalSeekBar

public class VerticalSeekBar extends SeekBar
{
	private boolean mIsDragging;
    private float mTouchDownY;
    private int mScaledTouchSlop;
    private boolean isInScrollingContainer = false;

    public boolean isInScrollingContainer()
    {
        return isInScrollingContainer;
    }

    public void setInScrollingContainer(boolean isInScrollingContainer)
    {
        this.isInScrollingContainer = isInScrollingContainer;
    }

  
    float mTouchProgressOffset;

    public VerticalSeekBar(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        mScaledTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    }

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

    public VerticalSeekBar(Context context)
    {
        super(context);
    }

    @Override
    protected 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());
    }

    @Override
    protected synchronized void onDraw(Canvas canvas)
    {
    	//顺针旋转90度，
        canvas.rotate(90);
        canvas.translate(0, -getWidth());
        //逆时针旋转90度
        //canvas.rotate(-90);
        //canvas.translate(-getHeight(), 0);//以原点纵坐标设置为负(滑块高度)
        super.onDraw(canvas);
    }

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

        switch (event.getAction())
        {
            case MotionEvent.ACTION_DOWN://按下
                if (isInScrollingContainer())
                {
                    mTouchDownY = event.getY();
                }
                else
                {
                    setPressed(true);
                    invalidate();
                    onStartTrackingTouch();
                    trackTouchEvent(event);
                    attemptClaimDrag();
                    onSizeChanged(getWidth(), getHeight(), 0, 0);
                }
                break;

            case MotionEvent.ACTION_MOVE://移动
                if (mIsDragging)
                {
                    trackTouchEvent(event);
                }
                else
                {
                    final float y = event.getY();
                    if (Math.abs(y - mTouchDownY) > mScaledTouchSlop)
                    {
                        setPressed(true);
                        invalidate();
                        onStartTrackingTouch();
                        trackTouchEvent(event);
                        attemptClaimDrag();
                    }
                }
                onSizeChanged(getWidth(), getHeight(), 0, 0);
                break;

            case MotionEvent.ACTION_UP://抬起
                if (mIsDragging)
                {
                    trackTouchEvent(event);
                    onStopTrackingTouch();
                    setPressed(false);
                }
                else
                {
                    onStartTrackingTouch();
                    trackTouchEvent(event);
                    onStopTrackingTouch();
                }
                onSizeChanged(getWidth(), getHeight(), 0, 0);
                invalidate();
                break;
        }
        return true;
    }

    private void trackTouchEvent(MotionEvent event)
    {
        final int height = getHeight();
        final int top = getPaddingTop();
        final int bottom = getPaddingBottom();
        final int available = height - top - bottom;

        int y = (int) event.getY();
        
        

        float scale;
        float progress = 0;

       
        if (y > height - bottom)
        {
            scale = 0.0f;
        }
        else if (y < top)
        {
            scale = 1.0f;
        }
        else
        {
            scale = (float) (available - y + top) / (float) available;
            progress = mTouchProgressOffset;
        }

        final int max = getMax();
        progress = progress + scale * max;
        progress = max - progress;//顺时针旋转90度使用，逆时针旋转90度屏蔽此段
        setProgress((int) progress);
    }

    /**
     * 按下
     */
    void onStartTrackingTouch()
    {
        mIsDragging = true;
    }

    /**
     * 松开
     */
    void onStopTrackingTouch()
    {
        mIsDragging = false;
    }

    private void attemptClaimDrag()
    {
        ViewParent p = getParent();
        if (p != null)
        {
            p.requestDisallowInterceptTouchEvent(true);
        }
    }

    @Override
    public synchronized void setProgress(int progress)
    {
        super.setProgress(progress);
        onSizeChanged(getWidth(), getHeight(), 0, 0);
    }
}

XML中：

在Activity中使用：

private VerticalSeekBar verticalSeekBar = null;

verticalSeekBar = (VerticalSeekBar)findViewById(R.id.verticalSeekBar);
verticalSeekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener()
{
@Override
public void onStopTrackingTouch(SeekBar seekBar){}

@Override
public void onStartTrackingTouch(SeekBar seekBar){}

@Override
public void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser)
{
TextView tv= (TextView)findViewById(R.id.textview1);
tv.setText(Integer.toString(progress));
}
});