Android修改字体样式的示例代码

在Android实际开发中根据UI的设计图，经常要去改变系统默认的字体样式

这样做会使apk变大很多啊

而且为什么android要使用ios的字体-_-#

单独设置字体样式

（1）Android系统提供了几种字体样式可供选择

通过设置typeface属性或者fontFamily属性设置

typeface属性：

normal
serif
sans
monospace

fontFamily属性：

casual
cursive
serif
monospace
sans-serif
sans-serif-condensed
serif-monospace
sans-serif-smallcaps

※typeface和fontFamily区别

android:typeface属性是增加API1

android:fontFamily在API16（4.1）中添加了属性

※当同时设置typeface和fontFamily时，只有fontFamily生效

查看一波TextView的源码

  private void setTypefaceFromAttrs(String familyName, int typefaceIndex, int styleIndex) {
    Typeface tf = null;
    if (familyName != null) {
      tf = Typeface.create(familyName, styleIndex);
      if (tf != null) {
        setTypeface(tf);
        return;
      }
    }
    switch (typefaceIndex) {
      case SANS:
        tf = Typeface.SANS_SERIF;
        break;

      case SERIF:
        tf = Typeface.SERIF;
        break;

      case MONOSPACE:
        tf = Typeface.MONOSPACE;
        break;
    }

    setTypeface(tf, styleIndex);
  }

从方法setTypefaceFromAttrs()看，如果你有set fontFamily属性，那么typefaceattribute将被忽略。

这边会发现这样设置typeface和fontFamily属性对中文不生效，这时候就需要引用外部的字体样式（这里谷歌设计规范推荐使用NOTO字体https://www.google.com/get/noto/）

（2）使用字体样式文件设置(otf，ttf文件都可以)

在assets下新建一个fonts文件，把字体样式文件放进去

在代码中设置

AssetManager mgr = getAssets();
Typeface tf = Typeface.createFromAsset(mgr, "fonts/NotoSansCJKsc-Black.otf");
tv_1.setTypeface(tf);

批量设置字体样式

（1）自定义TextView

public class CustomTextView extends TextView
{

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

  //重写设置字体方法
  @Override
  public void setTypeface(Typeface tf)
  {
    tf = Typeface.createFromAsset(getContext().getAssets(), "fonts/NotoSansCJKsc-Light.otf");
    super.setTypeface(tf);
  }
}

之后在XML布局文件中使用CustomTextView代替TextView

  <com.test.fontfamily.CustomTextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="6dp"
    android:text="自定义字体"
    android:textSize="24dp"
    /

（2）更换整个App的字体

思路：遍历找到所有的TextView然后替换字体

百度了一下找到下面工具类

package com.test.fontfamily;
import android.app.Application;
import android.content.Context;
import android.graphics.Typeface;
import android.support.annotation.NonNull;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.lang.ref.SoftReference;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
/**
* Created by Administrator on 2017/10/24.
*/
public class FontUtils
{
private static final String TAG = FontUtils.class.getSimpleName();
private Map<String, SoftReference<Typeface   mCache = new HashMap< ();
private static FontUtils sSingleton = null;
public static Typeface DEFAULT = Typeface.DEFAULT;
// disable instantiate
private FontUtils()
{
}
public static FontUtils getInstance()
{
// double check
if (sSingleton == null)
{
synchronized (FontUtils.class)
{
if (sSingleton == null)
{
sSingleton = new FontUtils();
}
}
}
return sSingleton;
}
/**
* <p Replace the font of specified view and it's children</p 
*
* @param root   The root view.
* @param fontPath font file path relative to 'assets' directory.
*/
public void replaceFontFromAsset(@NonNull View root, @NonNull String fontPath)
{
replaceFont(root, createTypefaceFromAsset(root.getContext(), fontPath));
}
/**
* <p Replace the font of specified view and it's children</p 
*
* @param root   The root view.
* @param fontPath font file path relative to 'assets' directory.
* @param style  One of {@link Typeface#NORMAL}, {@link Typeface#BOLD}, {@link Typeface#ITALIC}, {@link Typeface#BOLD_ITALIC}
*/
public void replaceFontFromAsset(@NonNull View root, @NonNull String fontPath, int style)
{
replaceFont(root, createTypefaceFromAsset(root.getContext(), fontPath), style);
}
/**
* <p Replace the font of specified view and it's children</p 
*
* @param root   The root view.
* @param fontPath The full path to the font data.
*/
public void replaceFontFromFile(@NonNull View root, @NonNull String fontPath)
{
replaceFont(root, createTypefaceFromFile(fontPath));
}
/**
* <p Replace the font of specified view and it's children</p 
*
* @param root   The root view.
* @param fontPath The full path to the font data.
* @param style  One of {@link Typeface#NORMAL}, {@link Typeface#BOLD}, {@link Typeface#ITALIC}, {@link Typeface#BOLD_ITALIC}
*/
public void replaceFontFromFile(@NonNull View root, @NonNull String fontPath, int style)
{
replaceFont(root, createTypefaceFromFile(fontPath), style);
}
/**
* <p Replace the font of specified view and it's children with specified typeface</p 
*/
private void replaceFont(@NonNull View root, @NonNull Typeface typeface)
{
if (root == null || typeface == null)
{
return;
}
if (root instanceof TextView)
{ // If view is TextView or it's subclass, replace it's font
TextView textView = (TextView) root;
// Extract previous style of TextView
int style = Typeface.NORMAL;
if (textView.getTypeface() != null)
{
style = textView.getTypeface().getStyle();
}
textView.setTypeface(typeface, style);
} else if (root instanceof ViewGroup)
{ // If view is ViewGroup, apply this method on it's child views
ViewGroup viewGroup = (ViewGroup) root;
for (int i = 0; i < viewGroup.getChildCount(); ++i)
{
replaceFont(viewGroup.getChildAt(i), typeface);
}
} // else return
}
/**
* <p Replace the font of specified view and it's children with specified typeface and text style</p 
*
* @param style One of {@link Typeface#NORMAL}, {@link Typeface#BOLD}, {@link Typeface#ITALIC}, {@link Typeface#BOLD_ITALIC}
*/
private void replaceFont(@NonNull View root, @NonNull Typeface typeface, int style)
{
if (root == null || typeface == null)
{
return;
}
if (style < 0 || style   3)
{
style = Typeface.NORMAL;
}
if (root instanceof TextView)
{ // If view is TextView or it's subclass, replace it's font
TextView textView = (TextView) root;
textView.setTypeface(typeface, style);
} else if (root instanceof ViewGroup)
{ // If view is ViewGroup, apply this method on it's child views
ViewGroup viewGroup = (ViewGroup) root;
for (int i = 0; i < viewGroup.getChildCount(); ++i)
{
replaceFont(viewGroup.getChildAt(i), typeface, style);
}
} // else return
}
/**
* <p Create a Typeface instance with specified font file</p 
*
* @param fontPath font file path relative to 'assets' directory.
* @return Return created typeface instance.
*/
private Typeface createTypefaceFromAsset(Context context, String fontPath)
{
SoftReference<Typeface  typefaceRef = mCache.get(fontPath);
Typeface typeface = null;
if (typefaceRef == null || (typeface = typefaceRef.get()) == null)
{
typeface = Typeface.createFromAsset(context.getAssets(), fontPath);
typefaceRef = new SoftReference< (typeface);
mCache.put(fontPath, typefaceRef);
}
return typeface;
}
private Typeface createTypefaceFromFile(String fontPath)
{
SoftReference<Typeface  typefaceRef = mCache.get(fontPath);
Typeface typeface = null;
if (typefaceRef == null || (typeface = typefaceRef.get()) == null)
{
typeface = Typeface.createFromFile(fontPath);
typefaceRef = new SoftReference< (typeface);
mCache.put(fontPath, typefaceRef);
}
return typeface;
}
/**
* <p Replace system default font. <b Note:</b you should also add code below to your app theme in styles.xml. </p 
* {@code <item name="android:typeface" monospace</item }
* <p The best place to call this method is {@link Application#onCreate()}, it will affect
* whole app font.If you call this method after view is visible, you need to invalid the view to make it effective.</p 
*
* @param context {@link Context Context}
* @param fontPath font file path relative to 'assets' directory.
*/
public void replaceSystemDefaultFontFromAsset(@NonNull Context context, @NonNull String fontPath)
{
replaceSystemDefaultFont(createTypefaceFromAsset(context, fontPath));
}
/**
* <p Replace system default font. <b Note:</b you should also add code below to your app theme in styles.xml. </p 
* {@code <item name="android:typeface" monospace</item }
* <p The best place to call this method is {@link Application#onCreate()}, it will affect
* whole app font.If you call this method after view is visible, you need to invalid the view to make it effective.</p 
*
* @param context {@link Context Context}
* @param fontPath The full path to the font data.
*/
public void replaceSystemDefaultFontFromFile(@NonNull Context context, @NonNull String fontPath)
{
replaceSystemDefaultFont(createTypefaceFromFile(fontPath));
}
/**
* <p Replace system default font. <b Note:</b you should also add code below to your app theme in styles.xml. </p 
* {@code <item name="android:typeface" monospace</item }
* <p The best place to call this method is {@link Application#onCreate()}, it will affect
* whole app font.If you call this method after view is visible, you need to invalid the view to make it effective.</p 
*/
private void replaceSystemDefaultFont(@NonNull Typeface typeface)
{
modifyObjectField(null, "MONOSPACE", typeface);
}
private void modifyObjectField(Object obj, String fieldName, Object value)
{
try
{
Field defaultField = Typeface.class.getDeclaredField(fieldName);
defaultField.setAccessible(true);
defaultField.set(obj, value);
} catch (NoSuchFieldException e)
{
e.printStackTrace();
} catch (IllegalAccessException e)
{
e.printStackTrace();
}
}
}

阅读源码发现这里面主要方法有

replaceFont()

替换一个页面中的所有字体。用递归的方式去查找view是否是TextView或者TextView的子类，然后进行替换。不过这种方法效率不高

用法：在页面中

FontUtils.getInstance().replaceFontFromAsset(View root, String fontPath)

modifyObjectField()

替换App所有字体。利用反射替换系统默认字体

用法：

a.新建一个BaseApplication继承Application在onCreate方法中

FontUtils.getInstance().replaceSystemDefaultFontFromAsset(this,"fonts/NotoSansCJKsc-Thin.otf");

b.在AppTheme中添加

<item name="android:typeface" monospace</item

c.清单文件中使用BaseApplication

以上就是本文的全部内容，希望对大家的学习有所帮助。