快速定位与修复
修改记录 | 修改时间 |
---|---|
新建 | 2021.01.09 |
出现问题时的调用方式:
public class I18nBaseActivity extends AppCompatActivity {
@Override
protected void attachBaseContext(Context newBase) {
//切换多语言,然后将新生成的 context 覆盖给 attachBaseContext()
Context context = MultiLanguageUtils.changeContextLocale(newBase);
super.attachBaseContext(context);
}
}
解决方法:
Androidx(appcompat:1.2.0) 中对attachBaseContext()
包装了一层ContextThemeWrapper
,但就是因为他给包的这一层逻辑有问题,导致了多语言切换时效。所以咱们手动给包一层
public class I18nBaseActivity extends AppCompatActivity {
@Override
protected void attachBaseContext(Context newBase) {
//切换多语言,然后将新生成的 context 覆盖给 attachBaseContext()
Context context = MultiLanguageUtils.changeContextLocale(newBase);
//兼容appcompat 1.2.0后切换语言失效问题
final Configuration configuration = context.getResources().getConfiguration();
final ContextThemeWrapper wrappedContext = new ContextThemeWrapper(context,
R.style.Base_Theme_AppCompat_Empty) {
@Override
public void applyOverrideConfiguration(Configuration overrideConfiguration) {
if (overrideConfiguration != null) {
overrideConfiguration.setTo(configuration);
}
super.applyOverrideConfiguration(overrideConfiguration);
}
};
super.attachBaseContext(wrappedContext);
}
}
封装
上面仅说明了怎么解决问题,没有体现多语言切换的实现。所以我封装了一个库(实质就是一个工具类),该库已经适配了该问题,大家可以直接copy出来使用
Github : github.com/StefanShan/…
详细排查过程与原理
最近项目升级为 Androidx,发现之前的多语言切换失效了。经过一点点排除方式排查,发现是由于升到 Androidx 后项目引入了 androidx.appcompat:appcompat:1.2.0
来替代之前的v7
包。那么根据多语言切换原理来看看是什么原因。
多语言切换原理:修改 context 的 Locale 配置,将新生成的 context 设置给 attachBaseContext 实现配置的替换。
先来看下 androidx 下的 AppCompatActivity# attachBaseContext() 源码
@Override
protected void attachBaseContext(Context newBase) {
super.attachBaseContext(getDelegate().attachBaseContext2(newBase));
}
哦~ 有个代理类处理了传入的 context,看下这个代理类 getDelegate()
的attachBaseContext2()
@NonNull
public AppCompatDelegate getDelegate() {
if (mDelegate == null) {
mDelegate = AppCompatDelegate.create(this, this); //代理对象是通过 AppCompatDelegate create出来的,那继续往下看
}
return mDelegate;
}
// 这里直接看 AppCompatDelegateImpl 类,该类是 AppCompatDelegate 类的实现类
@NonNull
@Override
@CallSuper
public Context attachBaseContext2(@NonNull final Context baseContext) {
//......
// If the base context is a ContextThemeWrapper (thus not an Application context)
// and nobody's touched its Resources yet, we can shortcut and directly apply our
// override configuration.
if (sCanApplyOverrideConfiguration
&& baseContext instanceof android.view.ContextThemeWrapper) {
final Configuration config = createOverrideConfigurationForDayNight(
baseContext, modeToApply, null);
if (DEBUG) {
Log.d(TAG, String.format("Attempting to apply config to base context: %s",
config.toString()));
}
try {
ContextThemeWrapperCompatApi17Impl.applyOverrideConfiguration(
(android.view.ContextThemeWrapper) baseContext, config);
return baseContext;
} catch (IllegalStateException e) {
if (DEBUG) {
Log.d(TAG, "Failed to apply configuration to base context", e);
}
}
}
// ......
// We can't trust the application resources returned from the base context, since they
// may have been altered by the caller, so instead we'll obtain them directly from the
// Package Manager.
final Configuration appConfig;
try {
appConfig = baseContext.getPackageManager().getResourcesForApplication(
baseContext.getApplicationInfo()).getConfiguration();
} catch (PackageManager.NameNotFoundException e) {
throw new RuntimeException("Application failed to obtain resources from itself", e);
}
// The caller may have directly modified the base configuration, so we'll defensively
// re-structure their changes as a configuration overlay and merge them with our own
// night mode changes. Diffing against the application configuration reveals any changes.
final Configuration baseConfig = baseContext.getResources().getConfiguration();
final Configuration configOverlay;
if (!appConfig.equals(baseConfig)) {
configOverlay = generateConfigDelta(appConfig, baseConfig); //这里是关键
if (DEBUG) {
Log.d(TAG,
"Application config (" + appConfig + ") does not match base config ("
+ baseConfig + "), using base overlay: " + configOverlay);
}
} else {
configOverlay = null;
if (DEBUG) {
Log.d(TAG, "Application config (" + appConfig + ") matches base context "
+ "config, using empty base overlay");
}
}
final Configuration config = createOverrideConfigurationForDayNight(
baseContext, modeToApply, configOverlay);
if (DEBUG) {
Log.d(TAG, String.format("Applying night mode using ContextThemeWrapper and "
+ "applyOverrideConfiguration(). Config: %s", config.toString()));
}
// Next, we'll wrap the base context to ensure any method overrides or themes are left
// intact. Since ThemeOverlay.AppCompat theme is empty, we'll get the base context's theme.
final ContextThemeWrapper wrappedContext = new ContextThemeWrapper(baseContext,
R.style.Theme_AppCompat_Empty);
wrappedContext.applyOverrideConfiguration(config);
// ......
return super.attachBaseContext2(wrappedContext);
}
@NonNull
private static Configuration generateConfigDelta(@NonNull Configuration base,
@Nullable Configuration change) {
final Configuration delta = new Configuration();
delta.fontScale = 0;
//......
//这里可以看到,如果两个配置相等,则直接跳过了,并没有给新创建的 delta 的 locale 赋值。
if (Build.VERSION.SDK_INT >= 24) {
ConfigurationImplApi24.generateConfigDelta_locale(base, change, delta);
} else {
if (!ObjectsCompat.equals(base.locale, change.locale)) {
delta.locale = change.locale;
}
}
//......
}
Ok,上面注释已经非常清晰了。这里简单总结下:
AppCompatActivity# attachBaseContext()
方法在 Androidx 进行了包装,具体实现在 AppCompatDelegateImpl# attachBaseContext2()
。
该包装方法实现了两套逻辑:
传入的 context 是经过 ContextThemeWrapper 封装的,则直接使用该 context 配置(包含语言)进行覆盖
传入的 context 未经过 ContextThemeWrapper 封装,则从 PackageManger 中获取配置(包含语言),然后和传入的 context 配置(包含语言)进行对比,并新创建了一个 configration 对象,如果两者有对比不同的配置则赋值给这个 configration,如果相同则跳过,最后将这个新建的 configration 作为最终配置结果进行覆盖。
而多语言问题就出现在 [2] 这套逻辑上,如果 PackageManager 与 传入的 context 某个配置项一致时就不会给新建的 configration 赋值该配置项。这就会导致当这一次切换成功后,杀死进程下次启动时,由于 packageManager 配置的语言 与 context 配置的语言一致,而直接跳过,并没有给新建的 configration进行赋值,最终表现就是多语言失效。
以上就是多语言切换在Androidx失效的踩坑解决记录的详细内容,更多关于多语言切换Androidx失效的资料请关注编程网其它相关文章!