Question

我在RelativeLayout 中创建了一个可拖动视图。但它似乎超越了RelativeLayout。

我只想在ViewGroup中创建一个View draggable

根据Screen，这个观点是draggable。它可以超越RelativeLayout的界限。我如何限制它在RelativeLayout中保持可拖动。

CustomImageButton

public class ImageButtonCustom extends ImageButton implements View.OnTouchListener{ float dX, dY; private RelativeLayout rootView; private ImageButtonCustom imageButtonCustom; private OnMoveListener onMoveListener; public ImageButtonCustom(Context context,RelativeLayout rootView){ super(context); this.rootView = rootView; init(); } public ImageButtonCustom(Context context) { super(context); init(); } public ImageButtonCustom(Context context, AttributeSet attrs) { super(context, attrs); init(); } public ImageButtonCustom(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } private void init(){ imageButtonCustom = this; setImageResource(R.drawable.upper_left); setBackgroundColor(Color.TRANSPARENT); setOnTouchListener(this); /*RelativeLayout.LayoutParams rl = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT); rl.addRule(RelativeLayout.ALIGN_BOTTOM);*/ rootView.addView(this); } @Override public boolean onTouch(View v, MotionEvent event) { switch (event.getAction() & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: dX = v.getX() - event.getRawX(); dY = v.getY() - event.getRawY(); break; case MotionEvent.ACTION_UP: break; case MotionEvent.ACTION_POINTER_DOWN: break; case MotionEvent.ACTION_POINTER_UP: break; case MotionEvent.ACTION_MOVE: v.animate() .x(event.getRawX() + dX) .y(event.getRawY() + dY) .setDuration(0) .start(); //no use of ViewPositionUtil onMoveListener.onMove(new Position());//positionXY); break; } rootView.invalidate(); return true; } public void setOnMoveListener(OnMoveListener onMoveListener){ this.onMoveListener = onMoveListener; } public float getCenterX(){ return getX() + getWidth() / 2; } public float getCenterY(){ return getY() + getHeight() / 2; } public interface OnMoveListener{ void onMove(Position positionXY); } }

修改

ImageButton是可拖动的，但它会outside of parent。限制它会在它的父布局中拖动。

Answer 1

这是我旧日记的摘录。希望它适合你。

public class OnDragTouchListener implements View.OnTouchListener {

    /**
     * Callback used to indicate when the drag is finished
     */
    public interface OnDragActionListener {
        /**
         * Called when drag event is started
         *
         * @param view The view dragged
         */
        void onDragStart(View view);

        /**
         * Called when drag event is completed
         *
         * @param view The view dragged
         */
        void onDragEnd(View view);
    }

    private View mView;
    private View mParent;
    private boolean isDragging;
    private boolean isInitialized = false;

    private int width;
    private float xWhenAttached;
    private float maxLeft;
    private float maxRight;
    private float dX;

    private int height;
    private float yWhenAttached;
    private float maxTop;
    private float maxBottom;
    private float dY;

    private OnDragActionListener mOnDragActionListener;

    public OnDragTouchListener(View view) {
        this(view, (View) view.getParent(), null);
    }

    public OnDragTouchListener(View view, View parent) {
        this(view, parent, null);
    }

    public OnDragTouchListener(View view, OnDragActionListener onDragActionListener) {
        this(view, (View) view.getParent(), onDragActionListener);
    }

    public OnDragTouchListener(View view, View parent, OnDragActionListener onDragActionListener) {
        initListener(view, parent);
        setOnDragActionListener(onDragActionListener);
    }

    public void setOnDragActionListener(OnDragActionListener onDragActionListener) {
        mOnDragActionListener = onDragActionListener;
    }

    public void initListener(View view, View parent) {
        mView = view;
        mParent = parent;
        isDragging = false;
        isInitialized = false;
    }

    public void updateBounds() {
        updateViewBounds();
        updateParentBounds();
        isInitialized = true;
    }

    public void updateViewBounds() {
        width = mView.getWidth();
        xWhenAttached = mView.getX();
        dX = 0;

        height = mView.getHeight();
        yWhenAttached = mView.getY();
        dY = 0;
    }

    public void updateParentBounds() {
        maxLeft = 0;
        maxRight = maxLeft + mParent.getWidth();

        maxTop = 0;
        maxBottom = maxTop + mParent.getHeight();
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (isDragging) {
            float[] bounds = new float[4];
            // LEFT
            bounds[0] = event.getRawX() + dX;
            if (bounds[0] < maxLeft) {
                bounds[0] = maxLeft;
            }
            // RIGHT
            bounds[2] = bounds[0] + width;
            if (bounds[2] > maxRight) {
                bounds[2] = maxRight;
                bounds[0] = bounds[2] - width;
            }
            // TOP
            bounds[1] = event.getRawY() + dY;
            if (bounds[1] < maxTop) {
                bounds[1] = maxTop;
            }
            // BOTTOM
            bounds[3] = bounds[1] + height;
            if (bounds[3] > maxBottom) {
                bounds[3] = maxBottom;
                bounds[1] = bounds[3] - height;
            }

            switch (event.getAction()) {
                case MotionEvent.ACTION_CANCEL:
                case MotionEvent.ACTION_UP:
                    onDragFinish();
                    break;
                case MotionEvent.ACTION_MOVE:
                    mView.animate().x(bounds[0]).y(bounds[1]).setDuration(0).start();
                    break;
            }
            return true;
        } else {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    isDragging = true;
                    if (!isInitialized) {
                        updateBounds();
                    }
                    dX = v.getX() - event.getRawX();
                    dY = v.getY() - event.getRawY();
                    if (mOnDragActionListener != null) {
                        mOnDragActionListener.onDragStart(mView);
                    }
                    return true;
            }
        }
        return false;
    }

    private void onDragFinish() {
        if (mOnDragActionListener != null) {
            mOnDragActionListener.onDragEnd(mView);
        }

        dX = 0;
        dY = 0;
        isDragging = false;
    }
}

您可以使用以下方式进行设置：

myView.setOnTouchListener(new OnDragTouchListener(myView));

或者直接在自定义视图的init方法中添加：

setOnTouchListener(new OnDragTouchListener(this));

Answer 2

您应该使用wrapper<decltype(&add), &add>::reg(L, "add");和rootView.getX()作为左侧和顶部bounderies ...而rootView.getY()作为右侧，(rootView.getX() + rootView.getWidth())作为底部边界。

您必须在ACTION_MOVE案例中的onTouch（）中编写边界逻辑。

希望这有帮助。

Answer 3

在OnTouch中，您可以计算移动视图的位置

case MotionEvent.ACTION_MOVE:
            v.animate()
                    .x(event.getRawX() + dX)
                    .y(event.getRawY() + dY)
                    .setDuration(0)
                    .start();

在移动之前，你应该检查x和y的边界。

case MotionEvent.ACTION_MOVE:
        float x = event.getRawX() + dX; float y = event.getRawY() + dY;
        if (x > boundaryRight) x = boundaryRight;
        else if (x < boundaryLeft) x = boundaryLeft;
        if (y < boundaryTop) y = boundaryTop;
        else if (y > boundaryBottom) y = boundaryBottom;
        v.animate()
                .x(x)
                .y(y)
                .setDuration(0)
                .start();

要在运行时计算RelativeLayout的边界，您应该使用Runnable或Listener或类似的Determining the size of an Android view at runtime

绑定视图以在RelativeLayout

3 个答案: