关于TextView中换行后对齐问题

貌似现在写的文章都是从业务方面或者是实现某些功能方面来写的。呃。。。
慢慢来吧，主要还是为了方便记录自己碰到问题。如果以后有机会了也开始写一些有深度的文章吧！
现在的道行还是不够深，源码虽然看过一些，但是深入的研究的还是有点少。算了还是先记录今天的问题吧！

今天记录的问题应该是大多数的开发经常碰得到的问题，在大多数的情况下是不需要考虑对齐问题的。

中文不对齐.png

英文不对齐.png

中英文状态下因为标点符号造成最后右侧不对齐，尤其是英文状态下单词在一行盛不下，造成空的更大。为了解决这一个问题，我们就需要自定义TextView了。当时代码已经有写久远了，代码出处已经无法考证。还是上代码吧！

public class TextAlignTextView extends TextView {

    private int mLineY;
    private int mViewWidth;
    public static final String TWO_CHINESE_BLANK = "  ";

    public TextAlignTextView (Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right,
                            int bottom) {
        super.onLayout(changed, left, top, right, bottom);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        TextPaint paint = getPaint();
        paint.setColor(getCurrentTextColor());
        paint.drawableState = getDrawableState();
        mViewWidth = getMeasuredWidth();
        String text = getText().toString();
        mLineY = 0;
        mLineY += getTextSize();
        Layout layout = getLayout();

        // layout.getLayout()在4.4.3出现NullPointerException
        if (layout == null) {
            return;
        }

        Paint.FontMetrics fm = paint.getFontMetrics();

        int textHeight = (int) (Math.ceil(fm.descent - fm.ascent));
        textHeight = (int) (textHeight * layout.getSpacingMultiplier() + layout
                .getSpacingAdd());
        //解决了最后一行文字间距过大的问题
        for (int i = 0; i < layout.getLineCount(); i++) {
            int lineStart = layout.getLineStart(i);
            int lineEnd = layout.getLineEnd(i);
            float width = StaticLayout.getDesiredWidth(text, lineStart,
                    lineEnd, getPaint());
            String line = text.substring(lineStart, lineEnd);

            if(i < layout.getLineCount() - 1) {
                if (needScale(line)) {
                    drawScaledText(canvas, lineStart, line, width);
                } else {
                    canvas.drawText(line, 0, mLineY, paint);
                }
            } else {
                canvas.drawText(line, 0, mLineY, paint);
            }
            mLineY += textHeight;
        }
    }

    private void drawScaledText(Canvas canvas, int lineStart, String line,
                                float lineWidth) {
        float x = 0;
        if (isFirstLineOfParagraph(lineStart, line)) {
            String blanks = "  ";
            canvas.drawText(blanks, x, mLineY, getPaint());
            float bw = StaticLayout.getDesiredWidth(blanks, getPaint());
            x += bw;

            line = line.substring(3);
        }

        int gapCount = line.length() - 1;
        int i = 0;
        if (line.length() > 2 && line.charAt(0) == 12288
                && line.charAt(1) == 12288) {
            String substring = line.substring(0, 2);
            float cw = StaticLayout.getDesiredWidth(substring, getPaint());
            canvas.drawText(substring, x, mLineY, getPaint());
            x += cw;
            i += 2;
        }

        float d = (mViewWidth - lineWidth) / gapCount;
        for (; i < line.length(); i++) {
            String c = String.valueOf(line.charAt(i));
            float cw = StaticLayout.getDesiredWidth(c, getPaint());
            canvas.drawText(c, x, mLineY, getPaint());
            x += cw + d;
        }
    }

    private boolean isFirstLineOfParagraph(int lineStart, String line) {
        return line.length() > 3 && line.charAt(0) == ' '
                && line.charAt(1) == ' ';
    }

    private boolean needScale(String line) {
        if (line == null || line.length() == 0) {
            return false;
        } else {
            return line.charAt(line.length() - 1) != '\n';
        }
    }

}

实际上就是通过动态改变每一行文字的宽度来达到我们想要的效果。
实际效果图

中文对齐.png

英文对齐.png

最终的效果就是看到两端对齐，而不是原来的参差不齐。
好了，这一块的记录就到这了，希望对您有所帮助！！！