Jface：自定义 FieldEditor 布局错误

Question

我想为首选项页面创建一个自定义 FieldEditor。目的是重写 ScaleFieldEditor 以提供一个带有两个标签的 Scale（一个显示最小值，另一个显示最大值）。

它做了一个。它正在工作，但当我将 FileFieldeditor 添加到首选项页面时，布局不好。

如果我在自定义 ScaleFieldEditor 之后立即添加 FileFieldEditor，情况会更糟： http://imageshack.us/g/844/customscalelayoutok.png/ （抱歉，我无法在这篇文章中添加图像）。

我制作了一个包含 2 个标签和比例的组合。我使用了 GridLayout：

public class ScaleWithLabelFieldEditor extends ScaleFieldEditor {

/**
 * The maximum value label
 */
private Label maxLabel;
/**
 * The minimum value label
 */
private Label minLabel;
/**
 * A composite that contains the scale and the min & max values label
 */
private Composite controls;

public ScaleWithLabelFieldEditor(String name, String labelText,
        Composite parent) {
    super(name, labelText, parent);
}

public ScaleWithLabelFieldEditor(String name, String labelText,
        Composite parent, int min, int max, int increment, int pageIncrement) {
    super(name, labelText, parent, min, max, increment, pageIncrement);
}

@Override
protected void doFillIntoGrid(Composite parent, int numColumns) {
    Control labelControl = getLabelControl(parent);
    GridData gd = new GridData();
    labelControl.setLayoutData(gd);

    controls = getControls(parent, 2);
    gd = new GridData(GridData.FILL_HORIZONTAL);
    gd.horizontalSpan = numColumns -1;
    gd.grabExcessHorizontalSpace = true;
    controls.setLayoutData(gd);
    updateControls();
    parent.layout();
}

/**
 * Initialize (if not done yet) the controls composite
 * 
 * @param parent
 *            the parent composite
 * @return the controls composite that contains the scaler and the min/max
 *         labels
 */
protected Composite getControls(Composite parent, int numColumns) {
    if (controls == null) {
        controls = new Composite(parent, SWT.NONE);
        GridLayout layout = new GridLayout(numColumns, false);
        layout.numColumns = numColumns;
        controls.setLayout(layout);

        // Initialize the min value label
        minLabel = getMinLabel(controls);
        minLabel.setLayoutData(new GridData(SWT.LEFT, SWT.TOP, false, false));
        // Initialize the max value label
        maxLabel = getMaxLabel(controls);
        maxLabel.setLayoutData(new GridData(SWT.RIGHT, SWT.TOP, false, false));
        // Initialize the scale
        scale = getScale(controls);
        scale.setLayoutData(new GridData(SWT.FILL, SWT.BOTTOM, true, false, numColumns, 1));

    }
    return controls;
}

/**
 * Nothing to do, already handle with controls composite
 */
@Override
protected void adjustForNumColumns(int numColumns) {
    // Nothing to do, already handle with controls composite
}

/**
 * Update the scale and the labels above
 */
protected void updateControls() {
    if (controls != null && !controls.isDisposed()) {
        // Update scale
        scale.setMinimum(getMinimum());
        scale.setMaximum(getMaximum());
        scale.setIncrement(getIncrement());
        scale.setPageIncrement(getPageIncrement());
        // Update labels
        maxLabel.setText(Integer.toString(getMaximum()));
        minLabel.setText(Integer.toString(getMinimum()));
    }
}

我应该怎么做才能使这个字段布局起作用？我是否错过了 GridLayout/GridData 使用中的某些内容？

Answer 1

问题似乎是您没有实现 adjustmentForNumColumns(int numColumns) 方法。添加 FileFieldEditor 后，列数从 2 更改为 3。并且您的字段编辑器必须适应当前的情况。

Answer 2

看起来horizo​​ntalSpan直到最后才跨越？因此，您可能应该尝试删除 gd.horizo​​ntalSpan = numColumns -1; 中的 -1;