Example usage for android.text Layout getLineTop

Introduction

In this page you can find the example usage for android.text Layout getLineTop.

Prototype

public abstract int getLineTop(int line);

Source Link

Document

Return the vertical position of the top of the specified line (0…getLineCount()).

Usage

From source file:com.amazon.android.ui.widget.ReadTextView.java

/**
 * Which line in the layout is the top visible line.
 *
 * @param layout Calculated text layout.
 * @param bounds Visible bounds in the coordinates of the TextView and layout.
 * @return The top visible line./*from   w  ww  .j  a v  a  2  s.  c  o m*/
 */
private int topVisibleLineOfText(final Layout layout, final Rect bounds) {

    final int lineCount = layout.getLineCount();
    for (int lineNum = 0; lineNum < lineCount; lineNum++) {
        final int top = layout.getLineTop(lineNum);
        if (top >= bounds.top && top <= bounds.bottom) {
            return lineNum;
        }
    }
    return lineCount;
}

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From source file:com.amazon.android.ui.widget.ReadTextView.java

/**
 * Draw a gradient on the text so that the bottom and top line have a faded effect if the user
 * can scroll in that direction.//from w  w  w .  ja  v a2s.c o  m
 */
private void updateGradient() {

    if (mText == null || mScrollView == null) {
        return;
    }

    final Layout layout = mText.getLayout();
    assert layout != null;

    final Rect bounds = new Rect();
    getTextBounds(bounds);
    final int topLine = topVisibleLineOfText(layout, bounds);
    final int bottomLine = bottomVisibleLineOfText(layout, bounds);
    final int fullHeight = layout.getHeight();

    if (fullHeight > 0) {

        final float bottomLineHeight = layout.getLineBottom(bottomLine) - layout.getLineTop(bottomLine);
        final float topLineHeight = layout.getLineBottom(topLine) - layout.getLineTop(topLine);
        this.setFadingEdgeLength((int) Math.max(topLineHeight, bottomLineHeight));
    }
}

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