textView排版文字对齐

偏执的太偏执、 2022-05-20 08:23 270阅读 0赞

具有特殊字符半角全角字符时排版文字对齐

import android.content.Context;
    import android.graphics.Canvas;
    import android.graphics.Paint;
    import android.text.Layout;
    import android.text.StaticLayout;
    import android.text.TextPaint;
    import android.util.AttributeSet;
    import android.widget.TextView;
    
    /** * 解决文字排版混乱参差不齐的问题 */
    public class JustifyTextView extends TextView { 
    
     private int mLineY;
     private int mViewWidth;
     public static final String TWO_CHINESE_BLANK = " ";
    
     public JustifyTextView(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';
      }
     }
    }