FileDocCategorySizeDatePackage
Selection.javaAPI DocAndroid 1.5 API12958Wed May 06 22:41:56 BST 2009android.text

Selection

public class Selection extends Object
Utility class for manipulating cursors and selections in CharSequences. A cursor is a selection where the start and end are at the same offset.

Fields Summary
public static final Object
SELECTION_START
public static final Object
SELECTION_END
Constructors Summary
private Selection()

 /* cannot be instantiated */
Methods Summary
private static intchooseHorizontal(Layout layout, int direction, int off1, int off2)

        int line1 = layout.getLineForOffset(off1);
        int line2 = layout.getLineForOffset(off2);

        if (line1 == line2) {
            // same line, so it goes by pure physical direction

            float h1 = layout.getPrimaryHorizontal(off1);
            float h2 = layout.getPrimaryHorizontal(off2);

            if (direction < 0) {
                // to left

                if (h1 < h2)
                    return off1;
                else
                    return off2;
            } else {
                // to right

                if (h1 > h2)
                    return off1;
                else
                    return off2;
            }
        } else {
            // different line, so which line is "left" and which is "right"
            // depends upon the directionality of the text

            // This only checks at one end, but it's not clear what the
            // right thing to do is if the ends don't agree.  Even if it
            // is wrong it should still not be too bad.
            int line = layout.getLineForOffset(off1);
            int textdir = layout.getParagraphDirection(line);

            if (textdir == direction)
                return Math.max(off1, off2);
            else
                return Math.min(off1, off2);
        }
public static booleanextendDown(Spannable text, Layout layout)
Move the selection end to the buffer offset physically below the current selection end.

        int end = getSelectionEnd(text);
        int line = layout.getLineForOffset(end);

        if (line < layout.getLineCount() - 1) {
            int move;

            if (layout.getParagraphDirection(line) ==
                layout.getParagraphDirection(line + 1)) {
                float h = layout.getPrimaryHorizontal(end);
                move = layout.getOffsetForHorizontal(line + 1, h);
            } else {
                move = layout.getLineStart(line + 1);
            }

            extendSelection(text, move);
            return true;
        } else if (end != text.length()) {
            extendSelection(text, text.length());
            return true;
        }

        return true;
public static booleanextendLeft(Spannable text, Layout layout)
Move the selection end to the buffer offset physically to the left of the current selection end.

        int end = getSelectionEnd(text);
        int to = layout.getOffsetToLeftOf(end);

        if (to != end) {
            extendSelection(text, to);
            return true;
        }

        return true;
public static booleanextendRight(Spannable text, Layout layout)
Move the selection end to the buffer offset physically to the right of the current selection end.

        int end = getSelectionEnd(text);
        int to = layout.getOffsetToRightOf(end);

        if (to != end) {
            extendSelection(text, to);
            return true;
        }

        return true;
public static final voidextendSelection(Spannable text, int index)
Move the selection edge to offset index.

        if (text.getSpanStart(SELECTION_END) != index)
            text.setSpan(SELECTION_END, index, index, Spanned.SPAN_POINT_POINT);
public static booleanextendToLeftEdge(Spannable text, Layout layout)

        int where = findEdge(text, layout, -1);
        extendSelection(text, where);
        return true;
public static booleanextendToRightEdge(Spannable text, Layout layout)

        int where = findEdge(text, layout, 1);
        extendSelection(text, where);
        return true;
public static booleanextendUp(Spannable text, Layout layout)
Move the selection end to the buffer offset physically above the current selection end.

        int end = getSelectionEnd(text);
        int line = layout.getLineForOffset(end);

        if (line > 0) {
            int move;

            if (layout.getParagraphDirection(line) ==
                layout.getParagraphDirection(line - 1)) {
                float h = layout.getPrimaryHorizontal(end);
                move = layout.getOffsetForHorizontal(line - 1, h);
            } else {
                move = layout.getLineStart(line - 1);
            }

            extendSelection(text, move);
            return true;
        } else if (end != 0) {
            extendSelection(text, 0);
            return true;
        }

        return true;
private static intfindEdge(Spannable text, Layout layout, int dir)

        int pt = getSelectionEnd(text);
        int line = layout.getLineForOffset(pt);
        int pdir = layout.getParagraphDirection(line);

        if (dir * pdir < 0) {
            return layout.getLineStart(line);
        } else {
            int end = layout.getLineEnd(line);

            if (line == layout.getLineCount() - 1)
                return end;
            else
                return end - 1;
        }
public static final intgetSelectionEnd(java.lang.CharSequence text)
Return the offset of the selection edge or cursor, or -1 if there is no selection or cursor.

        if (text instanceof Spanned)
            return ((Spanned) text).getSpanStart(SELECTION_END);
        else
            return -1;
public static final intgetSelectionStart(java.lang.CharSequence text)
Return the offset of the selection anchor or cursor, or -1 if there is no selection or cursor.

        if (text instanceof Spanned)
            return ((Spanned) text).getSpanStart(SELECTION_START);
        else
            return -1;
public static booleanmoveDown(Spannable text, Layout layout)
Move the cursor to the buffer offset physically below the current offset, or return false if the cursor is already on the bottom line.

        int start = getSelectionStart(text);
        int end = getSelectionEnd(text);

        if (start != end) {
            int min = Math.min(start, end);
            int max = Math.max(start, end);

            setSelection(text, max);

            if (min == 0 && max == text.length()) {
                return false;
            }

            return true;
        } else {
            int line = layout.getLineForOffset(end);

            if (line < layout.getLineCount() - 1) {
                int move;

                if (layout.getParagraphDirection(line) ==
                    layout.getParagraphDirection(line + 1)) {
                    float h = layout.getPrimaryHorizontal(end);
                    move = layout.getOffsetForHorizontal(line + 1, h);
                } else {
                    move = layout.getLineStart(line + 1);
                }

                setSelection(text, move);
                return true;
            }
        }

        return false;
public static booleanmoveLeft(Spannable text, Layout layout)
Move the cursor to the buffer offset physically to the left of the current offset, or return false if the cursor is already at the left edge of the line and there is not another line to move it to.

        int start = getSelectionStart(text);
        int end = getSelectionEnd(text);

        if (start != end) {
            setSelection(text, chooseHorizontal(layout, -1, start, end));
            return true;
        } else {
            int to = layout.getOffsetToLeftOf(end);

            if (to != end) {
                setSelection(text, to);
                return true;
            }
        }

        return false;
public static booleanmoveRight(Spannable text, Layout layout)
Move the cursor to the buffer offset physically to the right of the current offset, or return false if the cursor is already at at the right edge of the line and there is not another line to move it to.

        int start = getSelectionStart(text);
        int end = getSelectionEnd(text);

        if (start != end) {
            setSelection(text, chooseHorizontal(layout, 1, start, end));
            return true;
        } else {
            int to = layout.getOffsetToRightOf(end);

            if (to != end) {
                setSelection(text, to);
                return true;
            }
        }

        return false;
public static booleanmoveToLeftEdge(Spannable text, Layout layout)

        int where = findEdge(text, layout, -1);
        setSelection(text, where);
        return true;
public static booleanmoveToRightEdge(Spannable text, Layout layout)

        int where = findEdge(text, layout, 1);
        setSelection(text, where);
        return true;
public static booleanmoveUp(Spannable text, Layout layout)
Move the cursor to the buffer offset physically above the current offset, or return false if the cursor is already on the top line.

        int start = getSelectionStart(text);
        int end = getSelectionEnd(text);

        if (start != end) {
            int min = Math.min(start, end);
            int max = Math.max(start, end);

            setSelection(text, min);

            if (min == 0 && max == text.length()) {
                return false;
            }

            return true;
        } else {
            int line = layout.getLineForOffset(end);

            if (line > 0) {
                int move;

                if (layout.getParagraphDirection(line) ==
                    layout.getParagraphDirection(line - 1)) {
                    float h = layout.getPrimaryHorizontal(end);
                    move = layout.getOffsetForHorizontal(line - 1, h);
                } else {
                    move = layout.getLineStart(line - 1);
                }

                setSelection(text, move);
                return true;
            }
        }

        return false;
public static final voidremoveSelection(Spannable text)
Remove the selection or cursor, if any, from the text.

        text.removeSpan(SELECTION_START);
        text.removeSpan(SELECTION_END);
public static final voidselectAll(Spannable text)
Select the entire text.

        setSelection(text, 0, text.length());
public static voidsetSelection(Spannable text, int start, int stop)
Set the selection anchor to start and the selection edge to stop.

        // int len = text.length();
        // start = pin(start, 0, len);  XXX remove unless we really need it
        // stop = pin(stop, 0, len);

        int ostart = getSelectionStart(text);
        int oend = getSelectionEnd(text);
    
        if (ostart != start || oend != stop) {
            text.setSpan(SELECTION_START, start, start,
                         Spanned.SPAN_POINT_POINT|Spanned.SPAN_INTERMEDIATE);
            text.setSpan(SELECTION_END, stop, stop,
                         Spanned.SPAN_POINT_POINT);
        }
public static final voidsetSelection(Spannable text, int index)
Move the cursor to offset index.

        setSelection(text, index, index);