前言
app内字体大小调整应该是一个很常见的功能，绝大部分app里面都有可以设置字体大小的选项，网上实现方案也有很多，我这边给大家分享的是通过操作LayoutInflater.Factory2来实现
效果
设置完之后重启app字体全局生效【webp图有点简陋将就看下】
具体实现代码
主要实现类：
public class AppLayoutFactory implements LayoutInflater.Factory2 {
private static final String[] prefix = {"android.widget.", "com.juejin.widget"};
//系统inflater
private LayoutInflater inflater;
public AppLayoutFactory(Activity activity) {
this(activity.getLayoutInflater());
}
AppLayoutFactory(LayoutInflater inflater) {
this.inflater = inflater;
Log.i("AppLayoutFactory", "AppLayoutFactory: " + inflater);
LayoutInflaterCompat.setFactory2(inflater, this);
}
@Nullable
@Override
public View onCreateView(@Nullable View parent, @NonNull String name, @NonNull Context context, @NonNull AttributeSet attrs) {
return onCreateView(name, context, attrs);
}
@Nullable
@Override
public View onCreateView(@NonNull String name, @NonNull Context context, @NonNull AttributeSet attrs) {
Log.i("AppLayoutFactory", "onCreateView: name=====>" + name);
try {
View view;
if (name.startsWith(prefix[1])) {
view = getClazzView(context, name, attrs);
} else {
view = inflater.createView(name, prefix[0], attrs);
}
if (view instanceof TextView) {
boolean stableTextView = view instanceof StableFontSizeTextView;
Object tag = view.getTag();
Log.i("AppLayoutFactory",
"onCreateView: tag = " + (tag == null ? null : tag.toString()) + ", stableTextView = " + stableTextView);
//通过tag或者自定义TextView的方式不受全局字体大小设置而控制
if (!context.getString(R.string.stable_font_size).equals(tag)
&& !stableTextView) {
Log.i("AppLayoutFactory", "onCreateView: class====>" + view.getClass().getSimpleName());
//设置字体大小
AppFontHelper.getInstance().setAppTextSize((TextView) view);
}
}
return view;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/////////////////////////反射获取View///////////////////////////
//缓存构造方法
private static final HashMap<String, Constructor<? extends View>> sConstructorMap =
new HashMap<String, Constructor<? extends View>>();
private static final Class<?>[] constructorSignature = new Class[]{
Context.class, AttributeSet.class};
/**
* @param context
* @param name
* @param attrs
* @return 返回view
*/
private static View getClazzView(Context context, String name, AttributeSet attrs) {
View view = null;
try {
Constructor<? extends View> constructor = sConstructorMap.get(name);
if (constructor == null) {
Class<? extends View> clazz = Class.forName(name, false,
context.getClassLoader()).asSubclass(View.class);
constructor = clazz.getConstructor(constructorSignature);
constructor.setAccessible(true);
sConstructorMap.put(name, constructor);
}
view = constructor.newInstance(context, attrs);
} catch (Exception e) {
e.printStackTrace();
}
return view;
}
}
处理不受系统大字体控制【放在基类里面】
/**
* 禁止app字体大小跟随系统字体大小调节
*/
@Override
public Resources getResources() {
Resources resources = super.getResources();
if (resources != null) {
android.content.res.Configuration configuration = resources.getConfiguration();
if (configuration != null && configuration.fontScale != 1.0f) {
configuration.fontScale = 1.0f;
resources.updateConfiguration(configuration, resources.getDisplayMetrics());
}
}
return resources;
}
这里有个显示大小的选项还是会影响app内UI的显示，网上搜了一通暂时没找到解决方案，有方案的同学可以分享一下
基类的onCreate方法
这里插一句，网上有说法inflater是一个全局的单例，这个说法是有问题，下面是我两个activity中分别获得的inflater的实例，很明显是两个不一样的实例
2020-02-23 18:43:03.630 25223-25223/? I/AppLayoutFactory1: AppLayoutFactory: com.android.internal.policy.PhoneLayoutInflater@1dcf12f
2020-02-23 18:43:14.130 25223-25223/com.juejin I/AppLayoutFactory1: AppLayoutFactory: com.android.internal.policy.PhoneLayoutInflater@b3d0464
在基类初始化我们的inflater，设置定制的factory
protected void onCreate(@Nullable Bundle savedInstanceState) {
new AppLayoutFactory(this);//绑定每个inflater
super.onCreate(savedInstanceState);
}
new AppLayoutFactory(this);这行代码必须放在super之前否则会抛A factory has already been set on this LayoutInflater的错误；具体请看源码
activity的onCreate代码实现：
protected void onCreate(@Nullable Bundle savedInstanceState) {
final AppCompatDelegate delegate = getDelegate();
delegate.installViewFactory();
delegate.onCreate(savedInstanceState);
super.onCreate(savedInstanceState);
}
delegate.installViewFactory();此处会去初始化LayoutInflater的factory
public void installViewFactory() {
LayoutInflater layoutInflater = LayoutInflater.from(mContext);
if (layoutInflater.getFactory() == null) {
LayoutInflaterCompat.setFactory2(layoutInflater, this);
} else {
if (!(layoutInflater.getFactory2() instanceof AppCompatDelegateImpl)) {
Log.i(TAG, "The Activity's LayoutInflater already has a Factory installed"
+ " so we can not install AppCompat's");
}
}
}
具体这个错误是在LayoutInflater中的setFactory2抛出来的
/**
* Like {@link #setFactory}, but allows you to set a {@link Factory2}
* interface.
*/
public void setFactory2(Factory2 factory) {
if (mFactorySet) {
throw new IllegalStateException("A factory has already been set on this LayoutInflater");
}
if (factory == null) {
throw new NullPointerException("Given factory can not be null");
}
mFactorySet = true;
if (mFactory == null) {
mFactory = mFactory2 = factory;
} else {
mFactory = mFactory2 = new FactoryMerger(factory, factory, mFactory, mFactory2);
}
}
以上是基于compileSdkVersion=29 buildToolsVersion=29.0.2的代码，写的有问题的地方还望同学们指点一下
