如何在Android TextView中调整文字字距？

Question

有没有办法调整Android TextView中的字符间距？我相信这通常被称为“kerning”。

我知道android:textScaleX属性，但会压缩字符以及间距。

Answer 1

AFAIK，您无法调整TextView中的字距。如果您使用2D图形API自行绘制Canvas上的文本，则可以调整字距调整。

Answer 2

您也可以尝试使用SpannedString但你需要分析它，并改变每个词语

Answer 3

我发现调整字距的唯一途径字符间距，是创建一个自定义的字体中字形提前被改变。

Answer 4

我构建了一个扩展TextView的自定义类，并添加了一个方法“setSpacing”。解决方法与@Noah所说的类似。该方法在字符串的每个字母之间添加一个空格，并用SpannedString更改空格的TextScaleX，从而允许正负间距。

希望帮助别人^^

/** 
* Text view that allows changing the letter spacing of the text. 
* 
* @author Pedro Barros (pedrobarros.dev at gmail.com) 
* @since May 7, 2013 
*/ 

import android.content.Context; 
import android.text.Spannable; 
import android.text.SpannableString; 
import android.text.style.ScaleXSpan; 
import android.util.AttributeSet; 
import android.widget.TextView; 

public class LetterSpacingTextView extends TextView { 

    private float spacing = Spacing.NORMAL; 
    private CharSequence originalText = ""; 


    public LetterSpacingTextView(Context context) { 
     super(context); 
    } 

    public LetterSpacingTextView(Context context, AttributeSet attrs){ 
     super(context, attrs); 
    } 

    public LetterSpacingTextView(Context context, AttributeSet attrs, int defStyle){ 
     super(context, attrs, defStyle); 
    } 

    public float getSpacing() { 
     return this.spacing; 
    } 

    public void setSpacing(float spacing) { 
     this.spacing = spacing; 
     applySpacing(); 
    } 

    @Override 
    public void setText(CharSequence text, BufferType type) { 
     originalText = text; 
     applySpacing(); 
    } 

    @Override 
    public CharSequence getText() { 
     return originalText; 
    } 

    private void applySpacing() { 
     if (this == null || this.originalText == null) return; 
     StringBuilder builder = new StringBuilder(); 
     for(int i = 0; i < originalText.length(); i++) { 
      builder.append(originalText.charAt(i)); 
      if(i+1 < originalText.length()) { 
       builder.append("\u00A0"); 
      } 
     } 
     SpannableString finalText = new SpannableString(builder.toString()); 
     if(builder.toString().length() > 1) { 
      for(int i = 1; i < builder.toString().length(); i+=2) { 
       finalText.setSpan(new ScaleXSpan((spacing+1)/10), i, i+1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 
      } 
     } 
     super.setText(finalText, BufferType.SPANNABLE); 
    } 

    public class Spacing { 
     public final static float NORMAL = 0; 
    } 
} 

使用它：

LetterSpacingTextView textView = new LetterSpacingTextView(context); 
textView.setSpacing(10); //Or any float. To reset to normal, use 0 or LetterSpacingTextView.Spacing.NORMAL 
textView.setText("My text"); 
//Add the textView in a layout, for instance: 
((LinearLayout) findViewById(R.id.myLinearLayout)).addView(textView); 

Answer 5

如果有人正在寻找一种简单的方式，而不使用字距适用于任何字符串（技术上，CharSequence） TextView：

public static Spannable applyKerning(CharSequence src, float kerning) 
{ 
    if (src == null) return null; 
    final int srcLength = src.length(); 
    if (srcLength < 2) return src instanceof Spannable 
           ? (Spannable)src 
           : new SpannableString(src); 

    final String nonBreakingSpace = "\u00A0"; 
    final SpannableStringBuilder builder = src instanceof SpannableStringBuilder 
              ? (SpannableStringBuilder)src 
              : new SpannableStringBuilder(src); 
    for (int i = src.length() - 1; i >= 1; i--) 
    { 
     builder.insert(i, nonBreakingSpace); 
     builder.setSpan(new ScaleXSpan(kerning), i, i + 1, 
         Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 
    } 

    return builder; 
} 

Answer 6

这是我的解决方案，在每个字符之间添加均匀的间距（以像素为单位）。该跨度假定所有文本都在一行中。这基本上实现了@commonsWare的建议。

SpannableStringBuilder builder = new SpannableStringBuilder("WIDE normal"); 
builder.setSpan(new TrackingSpan(20), 0, 4, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 
... 

private static class TrackingSpan extends ReplacementSpan { 
    private float mTrackingPx; 

    public TrackingSpan(float tracking) { 
     mTrackingPx = tracking; 
    } 

    @Override 
    public int getSize(Paint paint, CharSequence text, 
     int start, int end, Paint.FontMetricsInt fm) { 
     return (int) (paint.measureText(text, start, end) 
      + mTrackingPx * (end - start - 1)); 
    } 

    @Override 
    public void draw(Canvas canvas, CharSequence text, 
     int start, int end, float x, int top, int y, 
     int bottom, Paint paint) { 
     float dx = x; 
     for (int i = start; i < end; i++) { 
      canvas.drawText(text, i, i + 1, dx, y, paint); 
      dx += paint.measureText(text, i, i + 1) + mTrackingPx; 
     } 
    } 
} 

Answer 7

还有@Pedro Barros的小编辑回答。如果使用SpannableString来设置它，则很有用。如果你想使某些字符不同的颜色：

private void applySpacing() { 
    SpannableString finalText; 

    if (!(originalText instanceof SpannableString)) { 
     if (this.originalText == null) return; 
     StringBuilder builder = new StringBuilder(); 
     for (int i = 0; i < originalText.length(); i++) { 
      builder.append(originalText.charAt(i)); 
      if (i + 1 < originalText.length()) { 
       builder.append("\u00A0"); 
      } 
     } 
     finalText = new SpannableString(builder.toString()); 
    } else { 
     finalText = (SpannableString) originalText; 
    } 

    for (int i = 1; i < finalText.length(); i += 2) { 
     finalText.setSpan(new ScaleXSpan((spacing + 1)/10), i, i + 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 
    } 
    super.setText(finalText, TextView.BufferType.SPANNABLE); 
} 

Answer 8

我想用@PedroBarros答案，但通过定义的间距应该在什么像素。

这里是我的编辑到applySpacing方法：

private void applySpacing() { 
    if (this == null || this.originalText == null) return; 

    Paint testPaint = new Paint(); 
    testPaint.set(this.getPaint()); 
    float spaceOriginalSize = testPaint.measureText("\u00A0"); 
    float spaceScaleXFactor = (spaceOriginalSize > 0 ? spacing/spaceOriginalSize : 1); 

    StringBuilder builder = new StringBuilder(); 
    for(int i = 0; i < originalText.length(); i++) { 
     builder.append(originalText.charAt(i)); 
     if(i+1 < originalText.length()) { 
      builder.append("\u00A0"); 
     } 
    } 
    SpannableString finalText = new SpannableString(builder.toString()); 
    if(builder.toString().length() > 1) { 
     for(int i = 1; i < builder.toString().length(); i+=2) { 
      finalText.setSpan(new ScaleXSpan(spaceScaleXFactor), i, i+1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 
     } 
    } 
    super.setText(finalText, BufferType.SPANNABLE); 
} 

我是一个初学者的Android开发人员，请随时让我知道这是不好的！

Answer 9

此答案对于想要在Canvas上绘制文本并使用drawText（这不是TextView中的文本）的人有帮助。

由于棒棒糖，Paint的方法setLetterSpacing可用。如果SDK是LOLLIPOP，则使用setLetterSpacing。否则，会调用类似于上面的@ dgmltn建议的方法：

if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) { 
     paint.setLetterSpacing(-0.04f); // setLetterSpacing is only available from LOLLIPOP and on 
     canvas.drawText(text, xOffset, yOffset, paint); 
    } else { 
     float spacePercentage = 0.05f; 
     drawKernedText(canvas, text, xOffset, yOffset, paint, spacePercentage); 
    } 


/** 
* Programatically drawn kerned text by drawing the text string character by character with a space in between. 
* Return the width of the text. 
* If canvas is null, the text won't be drawn, but the width will still be returned 
* kernPercentage determines the space between each letter. If it's 0, there will be no space between letters. 
* Otherwise, there will be space between each letter. The value is a fraction of the width of a blank space. 
*/ 
private int drawKernedText(Canvas canvas, String text, float xOffset, float yOffset, Paint paint, float kernPercentage) { 
    Rect textRect = new Rect(); 
    int width = 0; 
    int space = Math.round(paint.measureText(" ") * kernPercentage); 
    for (int i = 0; i < text.length(); i++) { 
     if (canvas != null) { 
      canvas.drawText(String.valueOf(text.charAt(i)), xOffset, yOffset, paint); 
     } 
     int charWidth; 
     if (text.charAt(i) == ' ') { 
      charWidth = Math.round(paint.measureText(String.valueOf(text.charAt(i)))) + space; 
     } else { 
      paint.getTextBounds(text, i, i + 1, textRect); 
      charWidth = textRect.width() + space; 
     } 
     xOffset += charWidth; 
     width += charWidth; 
    } 
    return width; 
} 

Answer 10

还有一个解决方案。

public static SpannableStringBuilder getSpacedSpannable(Context context, String text, int dp) { 
     if (text == null) return null; 
     if (dp < 0) throw new RuntimeException("WRONG SPACING " + dp); 
     Canvas canvas = new Canvas(); 
     Drawable drawable = ContextCompat.getDrawable(context, R.drawable.pixel_1dp); 
     Bitmap main = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888); 
     canvas.setBitmap(main); 
     drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight()); 
     drawable.draw(canvas); 
     SpannableStringBuilder builder = new SpannableStringBuilder(); 
     char[] array = text.toCharArray(); 
     Bitmap bitmap = Bitmap.createScaledBitmap(main, dp * main.getWidth(), main.getHeight(), false); 
     for (char ch : array) { 
      builder.append(ch); 
      builder.append(" "); 
      ImageSpan imageSpan = new ImageSpan(context, bitmap); 
      builder.setSpan(imageSpan, builder.length() - 1, builder.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 
     } 
     return builder; 
    } 

哪里pixel_1dp是XML：

<?xml version="1.0" encoding="utf-8"?> 
<shape xmlns:android="http://schemas.android.com/apk/res/android"> 

    <solid android:color="@android:color/transparent"/> 
    <size android:height="1dp" android:width="1dp"/> 

</shape> 

要设置这样的间隔使用代码：

textView.setText(getSpacedSpannable(context, textView.getText().toString(), <Your spacing DP>), TextView.BufferType.SPANNABLE);