Question

我创建了JTextpane并在textpane中插入了组件（像Jtextarea这样的组件）。（垂直滚动条）当我在JTextpane中插入新组件时，JTextpane的Jscrollpane会自动设置为底部。我想让它保持在最高位置。我怎么能这样做

由于 Sunil Kumar Sahoo

Answer 1

这是我使用的实用程序类。它可用于滚动到JScrollPane的顶部，底部，左侧，右侧或水平/垂直中心。

public final class ScrollUtil {
    public static final int NONE = 0, TOP = 1, VCENTER = 2, BOTTOM = 4, LEFT = 8, HCENTER = 16, RIGHT = 32;
    private static final int OFFSET = 100; // Required for hack (see below).

    private ScrollUtil() {
    }

    /**
     * Scroll to specified location.  e.g. <tt>scroll(component, BOTTOM);</tt>.
     *
     * @param c JComponent to scroll.
     * @param part Location to scroll to.  Should be a bit-wise OR of one or moe of the values:
     * NONE, TOP, VCENTER, BOTTOM, LEFT, HCENTER, RIGHT.
     */
    public static void scroll(JComponent c, int part) {
        scroll(c, part & (LEFT|HCENTER|RIGHT), part & (TOP|VCENTER|BOTTOM));
    }

    /**
     * Scroll to specified location.  e.g. <tt>scroll(component, LEFT, BOTTOM);</tt>.
     *
     * @param c JComponent to scroll.
     * @param horizontal Horizontal location.  Should take the value: LEFT, HCENTER or RIGHT.
     * @param vertical Vertical location.  Should take the value: TOP, VCENTER or BOTTOM.
     */
    public static void scroll(JComponent c, int horizontal, int vertical) {
        Rectangle visible = c.getVisibleRect();
        Rectangle bounds = c.getBounds();

        switch (vertical) {
            case TOP:     visible.y = 0; break;
            case VCENTER: visible.y = (bounds.height - visible.height) / 2; break;
            case BOTTOM:  visible.y = bounds.height - visible.height + OFFSET; break;
        }

        switch (horizontal) {
            case LEFT:    visible.x = 0; break;
            case HCENTER: visible.x = (bounds.width - visible.width) / 2; break;
            case RIGHT:   visible.x = bounds.width - visible.width + OFFSET; break;
        }

        // When scrolling to bottom or right of viewport, add an OFFSET value.
        // This is because without this certain components (e.g. JTable) would
        // not scroll right to the bottom (presumably the bounds calculation
        // doesn't take the table header into account.  It doesn't matter if
        // OFFSET is a huge value (e.g. 10000) - the scrollRectToVisible method
        // still works correctly.

        c.scrollRectToVisible(visible);
    }
}

Answer 2

我发现最简单的方法如下：

public void scroll(int vertical) {        
    switch (vertical) {
        case SwingConstants.TOP:
            getVerticalScrollBar().setValue(0);
            break;
        case SwingConstants.CENTER:
            getVerticalScrollBar().setValue(getVerticalScrollBar().getMaximum());
            getVerticalScrollBar().setValue(getVerticalScrollBar().getValue() / 2);
            break;
        case SwingConstants.BOTTOM:  
            getVerticalScrollBar().setValue(getVerticalScrollBar().getMaximum());
            break;
    }
}

我将它放在扩展JScrollPane的对象中，但您也可以在所有getVertivalScrollBar()之前添加JScrollPane的名称。 CENTER有两个setValue()，因为getMaximum()返回JScrollBar的底部，而不是它的最低值。这也可以使用getHorizontalScrollBar()代替getverticalScrollBar()进行水平滚动。

Answer 3

应该可以将DefaultCaret更新政策设置为NEVER_UPDATE。有关其他用途，请参阅文章Text Area Scrolling。

Answer 4

您可以使用各种方法，具体取决于滚动窗格内的内容。请参阅the tutorial，最后一节。

Answer 5

jScrollPane.getVerticalScrollBar（）的setValue（1）;

Answer 6

ScrollPane的滚动值始终在（0.0-1）之间
例如

0.0 = 0％
0.1 = 10％
0.2 = 20％
0.25 = 25％
....如此

然后您可以使用这些值调整滚动位置。例如，在JavaFX

// suppose this is the scrollpane
ScrollPane pane = new ScrollPane();

// to scroll the scrollpane horizontally 10% from its current position
pane.setHvalue(pane.getHvalue() + 0.1);

// to scroll 100%
pane.setHvalue(1);

and so on...

根据需要应用逻辑

Answer 7

这也可行：

JTextArea. myTextArea;

// ...

myTextArea.select(0, 0);   // force the scroll value to the top

如何调整滚动窗格中滚动的位置

7 个答案: