獲取textview行數

如果我們想獲取TextView內容的行數，TextView沒有提供現成的api供我們使用，需要我們自己獲取。

這裏提供一個間接的方法，通過StaticLayout來間接獲取行數。

下面是代碼：

public static int getTextViewLines(TextView textView, int textViewWidth) {
    int width = textViewWidth - textView.getCompoundPaddingLeft() - textView.getCompoundPaddingRight();
    StaticLayout staticLayout;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        staticLayout = getStaticLayout23(textView, width);
    } else {
        staticLayout = getStaticLayout(textView, width);
    }
    int lines = staticLayout.getLineCount();
    int maxLines = textView.getMaxLines();
    if (maxLines > lines) {
        return lines;
    }
    return maxLines;
}

/**
 * sdk>=23
 */
@RequiresApi(api = Build.VERSION_CODES.M)
private static StaticLayout getStaticLayout23(TextView textView, int width) {
    StaticLayout.Builder builder = StaticLayout.Builder.obtain(textView.getText(),
            0, textView.getText().length(), textView.getPaint(), width)
            .setAlignment(Layout.Alignment.ALIGN_NORMAL)
            .setTextDirection(TextDirectionHeuristics.FIRSTSTRONG_LTR)
            .setLineSpacing(textView.getLineSpacingExtra(), textView.getLineSpacingMultiplier())
            .setIncludePad(textView.getIncludeFontPadding())
            .setBreakStrategy(textView.getBreakStrategy())
            .setHyphenationFrequency(textView.getHyphenationFrequency())
            .setMaxLines(textView.getMaxLines() == -1 ? Integer.MAX_VALUE : textView.getMaxLines());
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        builder.setJustificationMode(textView.getJustificationMode());
    }
    if (textView.getEllipsize() != null && textView.getKeyListener() == null) {
        builder.setEllipsize(textView.getEllipsize())
                .setEllipsizedWidth(width);
    }
    return builder.build();
}

/**
 * sdk<23
 */
private static StaticLayout getStaticLayout(TextView textView, int width) {
    return new StaticLayout(textView.getText(),
            0, textView.getText().length(),
            textView.getPaint(), width, Layout.Alignment.ALIGN_NORMAL,
            textView.getLineSpacingMultiplier(),
            textView.getLineSpacingExtra(), textView.getIncludeFontPadding(), textView.getEllipsize(),
            width);
}