Question

我想创建一个只能在Y轴上拖动的可拖动视图。通常情况下，我会使用DragShadow并执行以下操作：

@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
    switch (motionEvent.getAction()) {
    case MotionEvent.ACTION_DOWN: {
        View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);

        view.startDrag(null, shadowBuilder, view, 0);
        view.setVisibility(View.INVISIBLE);
    } break;

    return true;
}

@Override
public boolean onDrag(View view, DragEvent dragEvent) {
    View sourceView = (View) dragEvent.getLocalState();

    float sourceX = sourceView.getX();
    float sourceY = sourceView.getY();
    float dropX = dragEvent.getX() - (sourceView.getWidth() / 2);
    float dropY = dragEvent.getY() - (sourceView.getHeight() / 2);

    switch(dragEvent.getAction()) {
    case DragEvent.ACTION_DRAG_EXITED : {
        TranslateAnimation animation = new TranslateAnimation(dropX - sourceX, 0, dropY - sourceY, 0);
        animation.setDuration(300);

        sourceView.startAnimation(animation);
        sourceView.setX(sourceX);
        sourceView.setY(sourceY);
        sourceView.setVisibility(View.VISIBLE);
    } break;
    case DragEvent.ACTION_DROP : {
        sourceView.setX(dropX);
        sourceView.setY(dropY);
        sourceView.setVisibility(View.VISIBLE);

        // TranslateAnimation animation = new TranslateAnimation(dropX - sourceX, 0, dropY - sourceY, 0);
        // animation.setDuration(300);

        // sourceView.startAnimation(animation);
        // sourceView.setX(sourceX);
        // sourceView.setY(sourceY);
    } break;
    }
}

问题在于我不希望{X轴上的View或DragShadow可以拖动。 X位置应始终保持不变，只允许更改Y轴。

我该怎么做？

Answer 1

简单的伎俩！用户VerticalSeekBar：

public class VerticalSeekBar extends SeekBar {
    /**
     * 
     */
    private OnSeekBarChangeListener onChangeListener = null;
    /**
     * 
     */
    private int lastProgress = 0;

    /**
     * 
     * @param context
     */
    public VerticalSeekBar(Context context) {
        super(context);
    }

    /**
     * 
     * @param context
     * @param attrs
     * @param defStyle
     */
    public VerticalSeekBar(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    /**
     * 
     * @param context
     * @param attrs
     */
    public VerticalSeekBar(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    /**
     * 
     */
    @Override
    protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) {
        super.onSizeChanged(height, width, oldHeight, oldWidth);
    }

    /**
     * 
     */
    @Override
    protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(heightMeasureSpec, widthMeasureSpec);

        this.setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth());
    }

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

        super.onDraw(c);
    }

    /**
     * 
     */
    @Override
    public void setOnSeekBarChangeListener(OnSeekBarChangeListener onChangeListener){
        this.onChangeListener = onChangeListener;
    }

    /**
     * 
     */
    @SuppressLint("ClickableViewAccessibility")
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (!isEnabled()) {
            return false;
        }

        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            this.onChangeListener.onStartTrackingTouch(this);

            this.setPressed(true);
            this.setSelected(true);

            break;
        case MotionEvent.ACTION_MOVE:
            super.onTouchEvent(event);

            int progress = getMax() - (int) (getMax() * event.getY() / getHeight());
            if(progress < 0) { progress = 0; }
            if(progress > getMax()) { progress = getMax(); }

            this.setProgress(progress);

            if(progress != this.lastProgress) {
                this.lastProgress = progress;
                this.onChangeListener.onProgressChanged(this, progress, true);
            }

            this.onSizeChanged(getWidth(), getHeight() , 0, 0);
            this.setPressed(true);
            this.setSelected(true);

            break;
        case MotionEvent.ACTION_UP:
            this.onChangeListener.onStopTrackingTouch(this);

            this.setPressed(false);
            this.setSelected(false);

            break;
        case MotionEvent.ACTION_CANCEL:
            super.onTouchEvent(event);

            this.setPressed(false);
            this.setSelected(false);

            break;
        }

        return true;
    }

    /**
     * 
     * @param progress
     */
    public synchronized void setProgressAndThumb(int progress) {
        this.setProgress(progress);
        this.onSizeChanged(getWidth(), getHeight() , 0, 0);

        if(progress != this.lastProgress) {
            this.lastProgress = progress;
            this.onChangeListener.onProgressChanged(this, progress, true);
        }
    }

    /**
     * 
     * @return
     */
    public synchronized int getMaximum() {
        return this.getMax();
    }

    /**
     * 
     * @param maximum
     */
    public synchronized void setMaximum(int maximum) {
        this.setMax(maximum);
    }
}

如何仅在y轴上拖动视图？

1 个答案: