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Android TextView 自动换行问题(zz)

2013年11月04日 ⁄ 综合 ⁄ 共 10173字 ⁄ 字号 评论关闭

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。

 

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:

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www.linuxidc.com

        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:

 

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