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的FieldEditor。其目的是覆盖ScaleFieldEditor以提供一个带有两个标签的比例(一个用于显示最小值，另一个用于显示最大值)。

它制造了一个。它可以工作，但布局不是很好，当我添加一个FileFieldeditor到首选项页面。

如果我在自定义的ScaleFieldEditor：http://imageshack.us/g/844/customscalelayoutok.png/后面立即添加FileFieldEditor，那就更糟了(对不起，我不能在这篇文章中添加图片)。

我做了一个包含2个标签和刻度的合成图。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()));
    }
}

我应该怎么做才能让这个字段布局正常工作？我是不是在GridLayout/GridData的使用中遗漏了什么？

Answer 1

问题似乎是，您没有实现adjustForNumColumns(int numColumns)方法。添加FileFieldEditor时，列数将从2更改为3。字段编辑器必须适应当前不能适应的列数。

Answer 2

看起来horizontalSpan是不是直到最后才会跨越？因此，您可能应该尝试删除gd.horizontalSpan = numColumns -1中的-1；