Android TextView标点符号换行问题（顺便学习Android自定义View）

Android的TextView在显示文字的时候有个问题就是一行还没显示满就跳到下一行，原因是：

1）
TextView在显示中文的时候
标点符号不能显示在一行的行首和行尾，如果一个标点符号刚好在一行的行尾，该标点符号就会连同前一个字符跳到下一行显示；

2）一个英文单词不能被显示在两行中（
TextView在显示英文时，标点符号是可以放在行尾的，但英文单词也不能分开
）；

如果只是想让标点符号可以显示在行尾，有一个简单的方法就是在标点符号后加一个空格，则该标点符号就可以显示在行尾了；

如果想要两端对齐的显示效果，有两种方法：

1）修改Android源代码；将frameworks/base/core/java/android/text下的StaticLayout.java文件中的如下代码：

if (c == ' ' || c == '/t' ||

((c == '.' || c == ',' || c == ':' || c == ';') &&

(j - 1 < here || !Character.isDigit(chs[j - 1 - start])) &&

(j + 1 >= next || !Character.isDigit(chs[j + 1 - start]))) ||

((c == '/' || c == '-') &&

(j + 1 >= next || !Character.isDigit(chs[j + 1 - start]))) ||

(c >= FIRST_CJK && isIdeographic(c, true) &&

j + 1 < next && isIdeographic(chs[j + 1 - start], false))) {

okwidth = w;

ok = j + 1;

if (fittop < oktop)

oktop = fittop;

if (fitascent < okascent)

okascent = fitascent;

if (fitdescent > okdescent)

okdescent = fitdescent;

if (fitbottom > okbottom)

okbottom = fitbottom;

}

去掉就可以了。去掉后标点符号可以显示在行首和行尾，英文单词也可以被分开在两行中显示。

但是我师傅说修改框架不美气，会影响其它应用程序，最好是能在应用层面解决问题。

所以就有了方法2；

2）自定义View显示文本

网上就有达人采用自定义View来解决这个问题，我做了实验并总结了一下：

原文地址：http://www.eoeandroid.com/thread-64055-1-1.html

自定义View的步骤：

1）继承View类或其子类，例子继承了TextView类；

2）写构造函数，通过XML获取属性（这一步中可以自定义属性，见例程）；

3）重写父类的某些函数，一般都是以on开头的函数，例子中重写了onDraw()和onMeasure()函数；

=========================CYTextView.java=============================

public class CYTextView extends TextView {

public static int m_iTextHeight; //文本的高度

public static int m_iTextWidth;//文本的宽度

private Paint mPaint = null;

private String string="";

private float LineSpace = 0;//行间距

public CYTextView(Context context, AttributeSet set)

{

super(context,set);

TypedArray typedArray = context.obtainStyledAttributes(set, R.styleable.CYTextView);

int width = typedArray.getInt(R.styleable.

CY

TextView_textwidth, 320);

float textsize = typedArray.getDimension(R.styleable.

CY

TextView_textSize, 24);

int textcolor = typedArray.getColor(R.styleable.

CY

TextView_textColor, -1442840576);

float linespace = typedArray.getDimension(R.styleable.

CY

TextView_lineSpacingExtra, 15);

int typeface = typedArray.getColor(R.styleable.

CY

TextView_typeface, 0);

typedArray.recycle();

//设置

CY

TextView的宽度和行间距

m_iTextWidth=width;

LineSpace=linespace;

// 构建paint对象

mPaint = new Paint();

mPaint.setAntiAlias(true);

mPaint.setColor(textcolor);

mPaint.setTextSize(textsize);

switch(typeface){

case 0:

mPaint.setTypeface(Typeface.DEFAULT);

break;

case 1:

mPaint.setTypeface(Typeface.SANS_SERIF);

break;

case 2:

mPaint.setTypeface(Typeface.SERIF);

break;

case 3:

mPaint.setTypeface(Typeface.MONOSPACE);

break;

default:

mPaint.setTypeface(Typeface.DEFAULT);

break;

}

}

@Override

protected void onDraw(Canvas canvas)

{

super.onDraw(canvas);

char ch;

int w = 0;

int istart = 0;

int m_iFontHeight;

int m_iRealLine=0;

int x=2;

int y=30;

Vector m_String=new Vector();

FontMetrics fm = mPaint.getFontMetrics();

m_iFontHeight = (int) Math.ceil(fm.descent - fm.top) + (int)LineSpace;//计算字体高度（字体高度＋行间距）

for (int i = 0; i < string.length(); i++)

{

ch = string.charAt(i);

float[] widths = new float[1];

String srt = String.valueOf(ch);

mPaint.getTextWidths(srt, widths);

if (ch == '/n'){

m_iRealLine++;

m_String.addElement(string.substring(istart, i));

istart = i + 1;

w = 0;

}else{

w += (int) (Math.ceil(widths[0]));

if (w > m_iTextWidth){

m_iRealLine++;

m_String.addElement(string.substring(istart, i));

istart = i;

i--;

w = 0;

}else{

if (i == (string.length() - 1)){

m_iRealLine++;

m_String.addElement(string.substring(istart, string.length()));

}

}

}

}

m_iTextHeight=m_iRealLine*m_iFontHeight+2;

canvas.setViewport(m_iTextWidth, m_iTextWidth);

for (int i = 0, j = 0; i < m_iRealLine; i++, j++)

{

canvas.drawText((String)(m_String.elementAt(i)), x, y+m_iFontHeight * j, mPaint);

}

}

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)

{

int measuredHeight = measureHeight(heightMeasureSpec);

int measuredWidth = measureWidth(widthMeasureSpec);

this.setMeasuredDimension(measuredWidth, measuredHeight);

this.setLayoutParams(new LinearLayout.LayoutParams(measuredWidth,measuredHeight));

super.onMeasure(widthMeasureSpec, heightMeasureSpec);

}

private int measureHeight(int measureSpec)

{

int specMode = MeasureSpec.getMode(measureSpec);

int specSize = MeasureSpec.getSize(measureSpec);

// Default size if no limits are specified.

initHeight();

int result = m_iTextHeight;

if (specMode == MeasureSpec.AT_MOST){

// Calculate the ideal size of your

// control within this maximum size.

// If your control fills the available

// space return the outer bound.

result = specSize;

}else if (specMode == MeasureSpec.EXACTLY){

// If your control can fit within these bounds return that value.

result = specSize;

}

return result;

}

private void initHeight()

{

//设置

CY

TextView的初始高度为0

m_iTextHeight=0;

//大概计算

CY

TextView所需高度

FontMetrics fm = mPaint.getFontMetrics();

int m_iFontHeight = (int) Math.ceil(fm.descent - fm.top) + (int)LineSpace;

int line=0;

int istart=0;

int w=0;

for (int i = 0; i < string.length(); i++)

{

char ch = string.charAt(i);

float[] widths = new float[1];

String srt = String.valueOf(ch);

mPaint.getTextWidths(srt, widths);

if (ch == '/n'){

line++;

istart = i + 1;

w = 0;

}else{

w += (int) (Math.ceil(widths[0]));

if (w > m_iTextWidth){

line++;

istart = i;

i--;

w = 0;

}else{

if (i == (string.length() - 1)){

line++;

}

}

}

}

m_iTextHeight=(line)*m_iFontHeight+2;

}

private int measureWidth(int measureSpec)

{

int specMode = MeasureSpec.getMode(measureSpec);

int specSize = MeasureSpec.getSize(measureSpec);

// Default size if no limits are specified.

int result = 500;

if (specMode == MeasureSpec.AT_MOST){

// Calculate the ideal size of your control

// within this maximum size.

// If your control fills the available space

// return the outer bound.

result = specSize;

}else if (specMode == MeasureSpec.EXACTLY){

// If your control can fit within these bounds return that value.

result = specSize;

}

return result;

}

public void SetText(String text)(注：此函数目前只有在UI线程中调用才可以把文本画出来，在其它线程中

无法画文本，找了好久找不到原因，求高手解答)

{

string = text;

// requestLayout();

// invalidate();

}

}

=======================attrs.xml===============================

该文件是自定义的属性，放在工程的res/values下

<resources>

<attr name="textwidth" format="integer"/>

<attr name="typeface">

<enum name="normal" value="0"/>

<enum name="sans" value="1"/>

<enum name="serif" value="2"/>

<enum name="monospace" value="3"/>

</attr>

<declare-styleable name="CYTextView">

<attr name="textwidth" />

<attr name="textSize" format="dimension"/>

<attr name="textColor" format="reference|color"/>

<attr name="lineSpacingExtra" format="dimension"/>

<attr name="typeface" />

</declare-styleable>

</resources>

=======================main.xml==========================

<?xml version="1.0" encoding="utf-8"?>

<ScrollView

xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="320px"

android:layout_height="320px"

android:background="#ffffffff"

>

<LinearLayout

xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<com.cy.CYTextView.CYTextView

xmlns:cy="http://schemas.android.com/apk/res/

com.cy.CYTextView

"

android:id="@+id/mv"

android:layout_height="wrap_content"

android:layout_width="wrap_content"

cy

:textwidth="320"

cy

:textSize="24sp"

cy

:textColor="#aa000000"

cy

:lineSpacingExtra="15sp"

cy

:typeface="serif">

</com.

cy

.CYTextView.CYTextView>

</LinearLayout>

</ScrollView>

蓝色代码即为自定义View，其中以cy命名空间开头的属性是自定义属性；

=======================Main.java=============================

public class Main extends Activity {

CYTextView mCYTextView;

String text = "android提供了精巧和有力的组件化模型构建用户的UI部分。主要是基于布局类：View和 ViewGroup。在此基础上，android平台提供了大量的预制的View和xxxViewGroup子 类，即布局（layout）和窗口小部件（widget）。可以用它们构建自己的UI。";

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

this.setContentView(R.layout.main);

mCYTextView = (CYTextView)findViewById(R.id.mv);

mCYTextView.SetText(text);

}

}

运行结果如下：