Question

我正在使用GridLayout，这就是我希望网格看起来像：

根据此https://docs.oracle.com/javase/7/docs/api/java/awt/GridLayout.html，这是ComponentOrientation的问题。

ComponentOrientation本身就是一个类，可以传递给setComponentOrientation类的Container方法，但似乎没有构造函数，也没有办法改变它的字段。

Answer 1

实际上，您可以通过扩展内置的GridLayout并覆盖单个方法来轻松实现此目的。我已经评论了实际上与父类实现不同的两行。其余注释是原始课程的一部分。

public class VerticalGridLayout
    extends GridLayout
{

  /**
   * Creates a grid layout with a default of one column per component, in a single row.
   */
  public VerticalGridLayout()
  {
    super();
  }

  /**
   * Creates a grid layout with the specified number of rows and columns. All components in the
   * layout are given equal size.
   * <p>
   * One, but not both, of <code>rows</code> and <code>cols</code> can be zero, which means that any
   * number of objects can be placed in a row or in a column.
   * 
   * @param rows the rows, with the value zero meaning any number of rows.
   * @param cols the columns, with the value zero meaning any number of columns.
   */
  public VerticalGridLayout( int rows, int cols )
  {
    super( rows, cols );
  }

  /**
   * Creates a grid layout with the specified number of rows and columns. All components in the
   * layout are given equal size.
   * <p>
   * In addition, the horizontal and vertical gaps are set to the specified values. Horizontal gaps
   * are placed between each of the columns. Vertical gaps are placed between each of the rows.
   * <p>
   * One, but not both, of <code>rows</code> and <code>cols</code> can be zero, which means that any
   * number of objects can be placed in a row or in a column.
   * <p>
   * All <code>GridLayout</code> constructors defer to this one.
   * 
   * @param rows the rows, with the value zero meaning any number of rows
   * @param cols the columns, with the value zero meaning any number of columns
   * @param hgap the horizontal gap
   * @param vgap the vertical gap
   * @exception IllegalArgumentException if the value of both <code>rows</code> and
   *              <code>cols</code> is set to zero
   */
  public VerticalGridLayout( int rows, int cols, int hgap, int vgap )
  {
    super( rows, cols, hgap, vgap );
  }

  @Override
  public void layoutContainer( Container parent )
  {
    synchronized ( parent.getTreeLock() )
    {
      Insets insets = parent.getInsets();
      int ncomponents = parent.getComponentCount();
      int nrows = getRows();
      int ncols = getColumns();
      boolean ltr = parent.getComponentOrientation().isLeftToRight();

      if ( ncomponents == 0 )
      {
        return;
      }
      if ( nrows > 0 )
      {
        ncols = (ncomponents + nrows - 1) / nrows;
      }
      else
      {
        nrows = (ncomponents + ncols - 1) / ncols;
      }
      // 4370316. To position components in the center we should:
      // 1. get an amount of extra space within Container
      // 2. incorporate half of that value to the left/top position
      // Note that we use trancating division for widthOnComponent
      // The reminder goes to extraWidthAvailable
      int totalGapsWidth = (ncols - 1) * getHgap();
      int widthWOInsets = parent.getWidth() - (insets.left + insets.right);
      int widthOnComponent = (widthWOInsets - totalGapsWidth) / ncols;
      int extraWidthAvailable = (widthWOInsets - (widthOnComponent * ncols + totalGapsWidth)) / 2;

      int totalGapsHeight = (nrows - 1) * getVgap();
      int heightWOInsets = parent.getHeight() - (insets.top + insets.bottom);
      int heightOnComponent = (heightWOInsets - totalGapsHeight) / nrows;
      int extraHeightAvailable = (heightWOInsets - (heightOnComponent * nrows + totalGapsHeight)) / 2;
      if ( ltr )
      {

        for ( int c = 0, x = insets.left + extraWidthAvailable; c < ncols; c++, x += widthOnComponent
            + getHgap() )
        {
          for ( int r = 0, y = insets.top + extraHeightAvailable; r < nrows; r++, y += heightOnComponent
              + getVgap() )
          {

            int i = c * nrows + r; // In the horizontal version, this is: r * ncols + c
            if ( i < ncomponents )
            {
              parent.getComponent( i ).setBounds( x, y, widthOnComponent, heightOnComponent );
            }
          }
        }
      }
      else
      {
        for ( int c = 0, x = (parent.getWidth() - insets.right - widthOnComponent)
            - extraWidthAvailable; c < ncols; c++, x -= widthOnComponent + getHgap() )
        {
          for ( int r = 0, y = insets.top + extraHeightAvailable; r < nrows; r++, y += heightOnComponent
              + getVgap() )
          {

            int i = c * nrows + r; // In the horizontal version, this is: r * ncols + c
            if ( i < ncomponents )
            {
              parent.getComponent( i ).setBounds( x, y, widthOnComponent, heightOnComponent );
            }
          }
        }
      }
    }
  }

}

在Java中使GridLayout成为垂直

1 个答案: