在Android的影子建设者 [英] Shadow builder in android

问题描述

我的工作为dragDrop比赛，但我有个小问题，当我在一个视图中单击阴影建设者第一次出现在正确的顶角，然后将其与触摸的地方移动。

另外的阴影助洗剂比初始视图小。我怎样才能使它作为初始看法？

 私人final类MyTouchListener实现OnTouchListener {
    公共布尔onTouch（查看视图，MotionEvent motionEvent）{        如果（motionEvent.getAction（）== MotionEvent.ACTION_DOWN）{
            ClipData数据= ClipData.newPlainText（，）;
            DragShadowBuilder shadowBuilder =新View.DragShadowBuilder（视图）;
            view.startDrag（数据，shadowBuilder，查看，0）;
            view.setVisibility（View.INVISIBLE）;
            返回true;
        }其他{
            返回false;
        }
    }
}
 

解决方案

我可能会迟到，但...
你必须计算触摸的点，你的拖动左上角之间的偏移，和与自定义DragShadowBuilder使用它。

下面是code的失调：

  @覆盖
公共布尔onTouch（查看视图，MotionEvent事件）{    开关（event.getAction（））{        案例MotionEvent.ACTION_DOWN：{            点偏移=新点（（int）的event.getX（），（INT）event.getY（））;            ClipData数据= ClipData.newPlainText（，）;
            DragShadowBuilder shadowBuilder =新CustomDragShadowBuilder（容器，偏移量）;
            view.startDrag（数据，shadowBuilder，容器，0）;
            view.setVisibility（View.INVISIBLE）;
        }
    }    返回true;
}
 

这里是code为自定义生成器：

 进口android.graphics.Point;
进口android.view.View;公共类CustomDragShadowBuilder扩展View.DragShadowBuilder {// ------------------------------------------------ ------------------------------------------
//私有属性：
私人点_offset;
// ------------------------------------------------ ------------------------------------------// ------------------------------------------------ ------------------------------------------
//构造函数：
公共CustomDragShadowBuilder（查看视图，点偏移）{    //商店传递给myDragShadowBuilder View参数。
    超（视图）;    //保存偏移：
    _offset =偏移;
}
// ------------------------------------------------ ------------------------------------------// ------------------------------------------------ ------------------------------------------
//定义发送拖影的尺寸和触摸点回到系统的回调。
@覆盖
公共无效onProvideShadowMetrics（点大小，点触控）{    //设置阴影大小：
    size.set（getView（）的getWidth（），getView（）的getHeight（））;    //设置触摸点的是在拖影的中间位置
    touch.set（_offset.x，_offset.y）;
}
// ------------------------------------------------ ------------------------------------------
}
 

I am working on a dragdrop game, but I have small problem, that when I click in a view the shadow builder appears first at the right-top-corner and then it moves with the touch place.

Also the shadow builder is smaller than the initial view. How can I make it as the initial view?

private final class MyTouchListener implements OnTouchListener {
    public boolean onTouch(View view, MotionEvent motionEvent) {

        if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
            ClipData data = ClipData.newPlainText("", "");
            DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
            view.startDrag(data, shadowBuilder, view, 0);
            view.setVisibility(View.INVISIBLE);
            return true;
        } else {
            return false;
        }
    }
}

解决方案

I may be late, but… You have to compute the offset between the touched point and your draggable top left corner, and use it with a custom DragShadowBuilder.

Here is the code for the offset :

@Override
public boolean onTouch(View view, MotionEvent event) {

    switch(event.getAction()) {

        case MotionEvent.ACTION_DOWN : {

            Point offset = new Point((int) event.getX(), (int) event.getY());

            ClipData data = ClipData.newPlainText("", "");
            DragShadowBuilder shadowBuilder = new CustomDragShadowBuilder(container, offset);
            view.startDrag(data, shadowBuilder, container, 0);
            view.setVisibility(View.INVISIBLE);
        }
    }

    return true;
}

And here is the code for the custom builder :

import android.graphics.Point;
import android.view.View;

public class CustomDragShadowBuilder extends View.DragShadowBuilder {

// ------------------------------------------------------------------------------------------
// Private attributes :
private Point _offset;
// ------------------------------------------------------------------------------------------



// ------------------------------------------------------------------------------------------
// Constructor :
public CustomDragShadowBuilder(View view, Point offset) {

    // Stores the View parameter passed to myDragShadowBuilder.
    super(view);

    // Save the offset :
    _offset = offset;
}
// ------------------------------------------------------------------------------------------



// ------------------------------------------------------------------------------------------
// Defines a callback that sends the drag shadow dimensions and touch point back to the system.
@Override
public void onProvideShadowMetrics (Point size, Point touch) {

    // Set the shadow size :
    size.set(getView().getWidth(), getView().getHeight());

    // Sets the touch point's position to be in the middle of the drag shadow
    touch.set(_offset.x, _offset.y);
}
// ------------------------------------------------------------------------------------------
}

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