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://.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，也希望大家多多支持。