Justify text in textview

前端 未结 7 2157
有刺的猬
有刺的猬 2020-12-08 12:40

In my app first I have textview to show text. Then I want to justify text but in android its not possible to justify text in textview. To justify text I am taking help from

7条回答
  •  南笙
    南笙 (楼主)
    2020-12-08 12:56

    import android.content.Context;
    import android.graphics.Canvas;
    import android.text.Layout;
    import android.text.StaticLayout;
    import android.text.TextPaint;
    import android.util.AttributeSet;
    import android.widget.TextView;
    
    
    public class JustifyTextView extends TextView {
    
    private int mLineY;
    private int mViewWidth;
    
    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();
        for (int i = 0; i < layout.getLineCount(); i++) {
            int lineStart = layout.getLineStart(i);
            int lineEnd = layout.getLineEnd(i);
            String line = text.substring(lineStart, lineEnd);
    
            float width = StaticLayout.getDesiredWidth(text, lineStart, lineEnd, getPaint());
            if (needScale(line,i)) {
                drawScaledText(canvas, lineStart, line, width);
            } else {
                canvas.drawText(line, 0, mLineY, paint);
            }
    
            mLineY += getLineHeight();
        }
    }
    
    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);
        }
    
        float d = (mViewWidth - lineWidth) / line.length() - 1;
        for (int i = 0; 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,int lineNumber) {
        Layout layout = getLayout();
        if (line.length() == 0 || layout.getLineCount() == 1 || lineNumber == (layout.getLineCount() - 1)) {
            return false;
        } else {
            return line.charAt(line.length() - 1) != '\n';
        }
    }
    
    }
    

    I modified code given by Sasikumar to correct followings.

    1. If lineCount() is 1, do not justify. (It was doing so)
    2. if lastLine, do not justify it. (it was going beyond justification)

    This is pure text only solution. Html does not work. no linebreak (\n) or any other character works. All spaces are removed. So its just for limited , pure text use.

提交回复
热议问题