android.text.Layout#getParagraphDirection ( )源码实例Demo

/**
 * If the direction of the URL has changed, update mUrlDirection and notify the
 * UrlDirectionListeners.
 */
private void updateUrlDirection() {
    Layout layout = getLayout();
    if (layout == null) return;

    int urlDirection;
    if (length() == 0) {
        urlDirection = LAYOUT_DIRECTION_LOCALE;
    } else if (layout.getParagraphDirection(0) == Layout.DIR_LEFT_TO_RIGHT) {
        urlDirection = LAYOUT_DIRECTION_LTR;
    } else {
        urlDirection = LAYOUT_DIRECTION_RTL;
    }

    if (urlDirection != mUrlDirection) {
        mUrlDirection = urlDirection;
        if (mUrlDirectionListener != null) {
            mUrlDirectionListener.onUrlDirectionChanged(urlDirection);
        }
    }
}
 

/**
 * If the direction of the URL has changed, update mUrlDirection and notify the
 * UrlDirectionListeners.
 */
private void updateUrlDirection() {
    Layout layout = getLayout();
    if (layout == null) return;

    int urlDirection;
    if (length() == 0) {
        urlDirection = LAYOUT_DIRECTION_LOCALE;
    } else if (layout.getParagraphDirection(0) == Layout.DIR_LEFT_TO_RIGHT) {
        urlDirection = LAYOUT_DIRECTION_LTR;
    } else {
        urlDirection = LAYOUT_DIRECTION_RTL;
    }

    if (urlDirection != mUrlDirection) {
        mUrlDirection = urlDirection;
        if (mUrlDirectionListener != null) {
            mUrlDirectionListener.onUrlDirectionChanged(urlDirection);
        }
    }
}
 

/**
 * If the direction of the URL has changed, update mUrlDirection and notify the
 * UrlDirectionListeners.
 */
private void updateUrlDirection() {
    Layout layout = getLayout();
    if (layout == null) return;

    int urlDirection;
    if (length() == 0) {
        urlDirection = LAYOUT_DIRECTION_LOCALE;
    } else if (layout.getParagraphDirection(0) == Layout.DIR_LEFT_TO_RIGHT) {
        urlDirection = LAYOUT_DIRECTION_LTR;
    } else {
        urlDirection = LAYOUT_DIRECTION_RTL;
    }

    if (urlDirection != mUrlDirection) {
        mUrlDirection = urlDirection;
        if (mUrlDirectionListener != null) {
            mUrlDirectionListener.onUrlDirectionChanged(urlDirection);
        }
    }
}
 

/**
 * Scrolls the specified widget to the specified coordinates, except
 * constrains the X scrolling position to the horizontal regions of
 * the text that will be visible after scrolling to the specified
 * Y position.
 */
public static void scrollTo(TextView widget, Layout layout, int x, int y) {
    final int horizontalPadding = widget.getTotalPaddingLeft() + widget.getTotalPaddingRight();
    final int availableWidth = widget.getWidth() - horizontalPadding;

    final int top = layout.getLineForVertical(y);
    Alignment a = layout.getParagraphAlignment(top);
    boolean ltr = layout.getParagraphDirection(top) > 0;

    int left, right;
    if (widget.getHorizontallyScrolling()) {
        final int verticalPadding = widget.getTotalPaddingTop() + widget.getTotalPaddingBottom();
        final int bottom = layout.getLineForVertical(y + widget.getHeight() - verticalPadding);

        left = Integer.MAX_VALUE;
        right = 0;

        for (int i = top; i <= bottom; i++) {
            left = (int) Math.min(left, layout.getLineLeft(i));
            right = (int) Math.max(right, layout.getLineRight(i));
        }
    } else {
        left = 0;
        right = availableWidth;
    }

    final int actualWidth = right - left;

    if (actualWidth < availableWidth) {
        if (a == Alignment.ALIGN_CENTER) {
            x = left - ((availableWidth - actualWidth) / 2);
        } else if ((ltr && (a == Alignment.ALIGN_OPPOSITE)) ||
                   (!ltr && (a == Alignment.ALIGN_NORMAL)) ||
                   (a == Alignment.ALIGN_RIGHT)) {
            // align_opposite does NOT mean align_right, we need the paragraph
            // direction to resolve it to left or right
            x = left - (availableWidth - actualWidth);
        } else {
            x = left;
        }
    } else {
        x = Math.min(x, right - availableWidth);
        x = Math.max(x, left);
    }

    widget.scrollTo(x, y);
}
 

private void draw(
        @NonNull View view,
        @NonNull Canvas canvas,
        @NonNull Layout layout
) {

    final CharSequence cs = layout.getText();
    if (!(cs instanceof Spanned)) {
        return;
    }
    final Spanned spanned = (Spanned) cs;

    final int save = canvas.save();
    try {
        canvas.translate(view.getPaddingLeft(), view.getPaddingTop());

        // TODO: block?
        // TODO: we must remove _original_ spans
        // TODO: cache (attach a listener?)
        // TODO: editor?

        final CodeSpan[] spans = spanned.getSpans(0, spanned.length(), CodeSpan.class);
        if (spans != null && spans.length > 0) {
            for (CodeSpan span : spans) {

                final int startOffset = spanned.getSpanStart(span);
                final int endOffset = spanned.getSpanEnd(span);

                final int startLine = layout.getLineForOffset(startOffset);
                final int endLine = layout.getLineForOffset(endOffset);

                // do we need to round them?
                final float left = layout.getPrimaryHorizontal(startOffset)
                        + (-1 * layout.getParagraphDirection(startLine) * paddingHorizontal);

                final float right = layout.getPrimaryHorizontal(endOffset)
                        + (layout.getParagraphDirection(endLine) * paddingHorizontal);

                final float top = getLineTop(layout, startLine, paddingVertical);
                final float bottom = getLineBottom(layout, endLine, paddingVertical);

                Debug.i(new RectF(left, top, right, bottom).toShortString());

                if (startLine == endLine) {
                    canvas.drawRect(left, top, right, bottom, paint);
                } else {
                    // draw first line (start until the lineEnd)
                    // draw everything in-between (startLine - endLine)
                    // draw last line (lineStart until the end

                    canvas.drawRect(
                            left,
                            top,
                            layout.getLineRight(startLine),
                            getLineBottom(layout, startLine, paddingVertical),
                            paint
                    );

                    for (int line = startLine + 1; line < endLine; line++) {
                        canvas.drawRect(
                                layout.getLineLeft(line),
                                getLineTop(layout, line, paddingVertical),
                                layout.getLineRight(line),
                                getLineBottom(layout, line, paddingVertical),
                                paint
                        );
                    }

                    canvas.drawRect(
                            layout.getLineLeft(endLine),
                            getLineTop(layout, endLine, paddingVertical),
                            right,
                            getLineBottom(layout, endLine, paddingVertical),
                            paint
                    );
                }
            }
        }
    } finally {
        canvas.restoreToCount(save);
    }
}