Android中的TextView控件默认是做不到两端对齐的，都是左对齐。可能的原因是安卓默认数字、字母不能为第一行以后每行的开头字符，因为数字、字母为半角字符，还有就是文字中的英文字符占用1个字节，而一个汉字占用两个字节。下面我就介绍下实现两端对齐的原理：

• 1、测量一个中文汉字所占用的宽度
• 2、根据TextView的宽度和一个汉字所占用的宽度以及字符之间的间隔计算出总行数。
• 3、根据padding和margin以及行高计算出TextView的总高度。
• 4、绘制每一行的每一个字符
  

效果如下：

具体代码如下：

package com.wedroid.framework.module.ui;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.text.TextPaint;import android.text.TextUtils;import android.util.AttributeSet;import android.view.ViewGroup.MarginLayoutParams;import android.view.ViewTreeObserver.OnPreDrawListener;import android.widget.TextView;public class WeDroidAlignTextView extends TextView { private boolean first = true; public WeDroidAlignTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); getViewTreeObserver().addOnPreDrawListener(new OnPreDrawListener() { @Override public boolean onPreDraw() { initTextInfo(); return true; } }); } public WeDroidAlignTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public WeDroidAlignTextView(Context context) { this(context, null, 0); } private float textSize; private float textLineHeight; private int top; private int y; private int lines; private int bottom; private int right; private int left; private int lineDrawWords; private char[] textCharArray; private float singleWordWidth; private float lineSpacingExtra; public void initTextInfo() { textSize = getTextSize(); textLineHeight = getLineHeight(); left = 0; right = getRight(); y = getTop(); // 要画的宽度 int drawTotalWidth = right - left; String text = getText().toString(); if (!TextUtils.isEmpty(text) && first) { textCharArray = text.toCharArray(); TextPaint mTextPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG); mTextPaint.density = getResources().getDisplayMetrics().density; mTextPaint.setTextSize(textSize); // 一个单词的的宽度 singleWordWidth = mTextPaint.measureText("一") + lineSpacingExtra; // 一行可以放多少个字符 lineDrawWords = (int) (drawTotalWidth / singleWordWidth); int length = textCharArray.length; lines = length / lineDrawWords; if ((length % lineDrawWords) > 0) { lines = lines + 1; } first = false; MarginLayoutParams layoutParams = (MarginLayoutParams) getLayoutParams(); int totalHeight = (int) (lines*textLineHeight+textLineHeight*2 + getPaddingBottom()+getPaddingTop()+layoutParams.bottomMargin+layoutParams.topMargin); setHeight(totalHeight); } } @Override protected void onDraw(Canvas canvas) { bottom = getBottom(); int drawTotalLine = lines; if(maxLine!=0&&drawTotalLine>maxLine){ drawTotalLine = maxLine; } for (int i = 0; i < drawTotalLine; i++) { try { int length = textCharArray.length; int mLeft = left; // 第i+1行开始的字符index int startIndex = (i * 1) * lineDrawWords; // 第i+1行结束的字符index int endTextIndex = startIndex + lineDrawWords; if (endTextIndex > length) { endTextIndex = length; y += textLineHeight; } else { y += textLineHeight; } for (; startIndex < endTextIndex; startIndex++) { char c = textCharArray[startIndex];// if (c == ' ') {// c = '\u3000';// } else if (c < '\177') {// c = (char) (c + 65248);// } canvas.drawText(String.valueOf(c), mLeft, y, getPaint()); mLeft += singleWordWidth; } } catch (Exception e) { e.printStackTrace(); } } } int maxLine; public void setMaxLines(int max){ this.maxLine = max; } public void setLineSpacingExtra(int lineSpacingExtra){ this.lineSpacingExtra = lineSpacingExtra; } /** * 判断是否为中文 * @return */ public static boolean containChinese(String string){ boolean flag = false; for (int i = 0; i < string.length(); i++) { char c = string.charAt(i); if ((c >= 0x4e00) && (c <= 0x9FA5)) { flag = true; } } return flag; } public static String ToDBC(String input) { // 导致TextView异常换行的原因：安卓默认数字、字母不能为第一行以后每行的开头字符，因为数字、字母为半角字符 // 所以我们只需要将半角字符转换为全角字符即可 char c[] = input.toCharArray(); for (int i = 0; i < c.length; i++) { if (c[i] == ' ') { c[i] = '\u3000'; } else if (c[i] < '\177') { c[i] = (char) (c[i] + 65248); } } return new String(c); }}

希望本文所述对大家学习Android程序设计有所帮助。