問題描述

我想知道是否可以在鼠標上移時獲取列表中的項目?我在網上搜索并找到了許多使用 X 和 Y 坐標但沒有使用列表的 SWT 表示例.我基本上在做的是實現一個列表，其中項目的順序可以通過拖放來更改.為此，我需要能夠獲取放置位置下的項目，以便我可以將該項目與拖動的項目交換.

I wanted to know if its possible to get the item in the list on mouse up? I searched online and found many examples for SWT table using the X and the Y coordinate but none using a list. What I am basically doing is implementing a list in which the order of the items can be changed by drag and drop. For this I need to be able to get the item under the drop location so that I can swap that item with the dragged item.

推薦答案

List#getItemHeight() 返回一個item所占區域的高度.有了這些信息和 getTopIndex()，您應該能夠在給定的 x 和 y 坐標處計算項目.

List#getItemHeight() returns the height of the area one item occupies. With that information and getTopIndex()you should be able to compute the item at a given x and y coordinate.

list.addListener( SWT.MouseDown, new Listener() {
  @Override
  public void handleEvent( Event event ) {
    int itemTop = 0;
    for( int i = 0; i < list.getItemCount(); i++ ) {
      if( event.y >= itemTop && event.y <= itemTop + list.getItemHeight() ) {
        System.out.println( "Click on item " + list.getItem( list.getTopIndex()  + i ) );
      }
      itemTop += list.getItemHeight();
    }
  }
} );

或者，您可以使用帶有 setHeaderVisible( false ) 的單列表來模擬列表小部件.該表提供了更好的開箱即用拖放支持.

Alternatively you could use a single-columned table with setHeaderVisible( false ) to emulate a list widget. The table provides better drag and drop support out of the box.

這篇關于在 Mouse Up 上獲取 SWT 列表中的項目的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！