Java JTextComponent.scrollRectToVisible方法代码示例

import javax.swing.text.JTextComponent; //导入方法依赖的package包/类
public void actionPerformed(ActionEvent evt, JTextComponent target) {
    if (target != null) {
        // Scroll the component down due to the extra visual space becomes visible.
        Rectangle bounds = target.getBounds();
        bounds.x = 0;
        bounds.y = bounds.height;
        bounds.width = 1;
        bounds.height = 1;
        target.scrollRectToVisible(bounds);

        Caret caret = target.getCaret();
        int dot = target.getDocument().getLength(); // end of document
        boolean select = selectionEndAction.equals(getValue(Action.NAME));
        if (select) {
            caret.moveDot(dot);
        } else {
            caret.setDot(dot);
        }
    }
}
 

import javax.swing.text.JTextComponent; //导入方法依赖的package包/类
/**
 * Scrolls the specified text component so the text between the starting and ending index are visible.
 */
public static void scrollToText(JTextComponent textComponent, int startingIndex, int endingIndex) {
    try {
        Rectangle startingRectangle = textComponent.modelToView(startingIndex);
        Rectangle endDingRectangle = textComponent.modelToView(endingIndex);

        Rectangle totalBounds = startingRectangle.union(endDingRectangle);

        textComponent.scrollRectToVisible(totalBounds);
        textComponent.repaint();
    } catch (BadLocationException e) {
        e.printStackTrace();
    }
}
 

import javax.swing.text.JTextComponent; //导入方法依赖的package包/类
/**
 * Ensure that the given region will be visible in the view
 * with the appropriate find insets.
 */
private void ensureVisible(JTextComponent c, int startOffset, int endOffset, Insets extraInsets) {
    try {
        Rectangle startBounds = c.modelToView(startOffset);
        Rectangle endBounds = c.modelToView(endOffset);
        if (startBounds != null && endBounds != null) {
            startBounds.add(endBounds);
            if (extraInsets != null) {
                Rectangle visibleBounds = c.getVisibleRect();
                int extraTop = (extraInsets.top < 0)
                    ? -extraInsets.top * visibleBounds.height / 100 // percentage
                    : extraInsets.top * endBounds.height; // line count
                startBounds.y -= extraTop;
                startBounds.height += extraTop;
                startBounds.height += (extraInsets.bottom < 0)
                    ? -extraInsets.bottom * visibleBounds.height / 100 // percentage
                    : extraInsets.bottom * endBounds.height; // line count
                int extraLeft = (extraInsets.left < 0)
                    ? -extraInsets.left * visibleBounds.width / 100 // percentage
                    : extraInsets.left * endBounds.width; // char count
                startBounds.x -= extraLeft;
                startBounds.width += extraLeft;
                startBounds.width += (extraInsets.right < 0)
                    ? -extraInsets.right * visibleBounds.width / 100 // percentage
                    : extraInsets.right * endBounds.width; // char count
            }
            c.scrollRectToVisible(startBounds);
        }
    } catch (BadLocationException e) {
        // do not scroll
    }
}
 

import javax.swing.text.JTextComponent; //导入方法依赖的package包/类
public void actionPerformed(ActionEvent evt, JTextComponent target) {
    if (target != null) {
        Caret caret = target.getCaret();
        BaseDocument doc = (BaseDocument)target.getDocument();
        try {
            int dot = caret.getDot();
            // #232675: if bounds are defined, use them rather than line start/end
            Object o = target.getClientProperty(PROP_NAVIGATE_BOUNDARIES);
            PositionRegion bounds = null;
            int lineStartPos = Utilities.getRowStart(target, dot);
            
            if (o instanceof PositionRegion) {
                bounds = (PositionRegion)o;
                int start = bounds.getStartOffset();
                int end = bounds.getEndOffset();
                int boundLineStart = Utilities.getRowStart(target, start);
                // refinement: only use the boundaries if the caret is at the same line
                // as boundary start; otherwise ignore the boundary and use document lines.
                if (boundLineStart == lineStartPos && dot > start && dot <= end) {
                    // move to the region start
                    dot = start;
                } else {
                    bounds = null;
                }
            }
            
            if (bounds == null) {
                if (homeKeyColumnOne) { // to first column
                    dot = lineStartPos;
                } else { // either to line start or text start
                    int textStartPos = Utilities.getRowFirstNonWhite(doc, lineStartPos);
                    if (textStartPos < 0) { // no text on the line
                        textStartPos = Utilities.getRowEnd(target, lineStartPos);
                    }
                    if (dot == lineStartPos) { // go to the text start pos
                        dot = textStartPos;
                    } else if (dot <= textStartPos) {
                        dot = lineStartPos;
                    } else {
                        dot = textStartPos;
                    }
                }
            }
            // For partial view hierarchy check bounds
            dot = Math.max(dot, target.getUI().getRootView(target).getStartOffset());
            String actionName = (String) getValue(Action.NAME);
            boolean select = selectionBeginLineAction.equals(actionName)
                    || selectionLineFirstColumnAction.equals(actionName);
            
            // If possible scroll the view to its begining horizontally
            // to ease user's orientation in the code.
            Rectangle r = target.modelToView(dot);
            Rectangle visRect = target.getVisibleRect();
            if (r.getMaxX() < visRect.getWidth()) {
                r.x = 0;
                target.scrollRectToVisible(r);
            }
            target.putClientProperty("navigational.action", SwingConstants.WEST);
            if (select) {
                caret.moveDot(dot);
            } else {
                caret.setDot(dot);
            }
        } catch (BadLocationException e) {
            target.getToolkit().beep();
        }
    }
}