Android open source TextView中的文本自动对齐

最新推荐文章于 2021-01-26 14:50:52 发布

原创最新推荐文章于 2021-01-26 14:50:52 发布 · 618 阅读

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#Android open source

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本文介绍了一个Android开源项目，该项目提供了一种方法来实现TextView中的文本自动对齐功能。通过使用JustifyTextView组件，开发者可以轻松地使文本在不同宽度的视图中均匀分布，提高阅读体验。

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Android open source TextView中的文本自动对齐

Android open source:justifytext

https://github.com/ufo22940268/android-justifiedtextview

引用

compile 'me.biubiubiu.justifytext:library:1.1'

布局

<me.biubiubiu.justifytext.library.JustifyTextView
	android:id="@+id/text"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:text="@string/user_lisence_information" />

相关修改

package com.fate.opensource_justifytext;

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;

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';
        }
    }

}