是否可以调用主活动(Android)中另一个活动的静态类中定义的方法

Question

所以我有一个方法loadLocale()，我想在MainActivity中使用它来设置存储在共享首选项中的用户首选语言。设置活动代码如下所示：

public class SettingsActivity extends PreferenceActivity  {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AppPreferenceFragment appPreferenceFragment=(AppPreferenceFragment)getFragmentManager().findFragmentByTag("PreferenceFragment");
if(appPreferenceFragment==null)
appPreferenceFragment = new AppPreferenceFragment();
getFragmentManager()
.beginTransaction()
.replace(android.R.id.content, appPreferenceFragment, "PreferenceFragment")
.commit();
}

public static class AppPreferenceFragment extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener, Preference.OnPreferenceClickListener
{

@Override
public void onCreate(final Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
loadLocale();
//Some other code
Preference pref_al = findPreference("select_app_language");
pref_al.setOnPreferenceClickListener(this);
}

@Override
public boolean onPreferenceClick(Preference preference) {
//SOME CODE
else if (preference.getKey().compareTo("select_pref_language")==0){
setupSelectLanguageDialog();
}
return false;
}

public void setupAppLanguageDialog()
{
AlertDialog langChangeDialog;
CharSequence[] changeLangList = {"English", "हिन्दी"};
AlertDialog.Builder mBuilder = new AlertDialog.Builder(getActivity());
mBuilder.setTitle("Choose language");
mBuilder.setSingleChoiceItems(changeLangList, -1, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
if (i==0)
{
setLocale("en");
getActivity().recreate();
}
else
{
setLocale("hi");
getActivity().recreate();
}
dialogInterface.dismiss();
}
});
langChangeDialog =mBuilder.create();
langChangeDialog.show();
}
public void setLocale(String lang) {
Locale locale = new Locale(lang);
Locale.setDefault(locale);
Configuration config = new Configuration();
config.locale = locale;
getResources().updateConfiguration(config ,getResources().getDisplayMetrics());
DataRepository.setAppLanguage(lang);
Log.v("locale",DataRepository.getUserData("app_lang"));
}
//load langauge saved in shared prefrences
public void loadLocale()
{
String app_lang= DataRepository.getAppLanguage();
if(InputValidator.isNullorEmpty(app_lang) || app_lang.equals(Constants.NO_DATA)){
Log.v("Locale","Empty");
return;
}
setLocale(app_lang);
Log.v("loaded Locale",app_lang);
}

我想在我的mainActivity中调用loadLocale()方法，这样当应用程序启动时，默认情况下会选择首选语言。我的mainActivity看起来像：

public class MainActivity extends AppCompatActivity {
//Some declarations
@Override
protected void onCreate(Bundle savedInstanceState) {

//I want to set my app language here by calling loadLocale()
//loadLocale();
//other code
}

我可以重新编写两个函数MainActivity。有更好的方法吗？

注意：DataRepository.getAppLanguage()和DataRepository.setAppLanguage()是通过SharedPreferences 存储和获取应用程序语言的方法

Answer 1

为什么不只创建一个只有静态函数的类，如果需要，传递参数，如果需要添加返回类型。然后你可以在任何地方打电话给它。示例：

class Helper {
public static void loadLocale(Context context)
{
String app_lang= DataRepository.getAppLanguage();
if(InputValidator.isNullorEmpty(app_lang) || app_lang.equals(Constants.NO_DATA)){
Log.v("Locale","Empty");
return;
}
setLocale(app_lang, context);
Log.v("loaded Locale",app_lang);
}
public static void setLocale(String lang, Context context) {
Locale locale = new Locale(lang);
Locale.setDefault(locale);
Configuration config = new Configuration();
config.locale = locale;
context.getResources().updateConfiguration(config ,context.getResources().getDisplayMetrics());
DataRepository.setAppLanguage(lang);
Log.v("locale",DataRepository.getUserData("app_lang"));
}
}

Answer 2

从语法上讲，您应该能够通过调用new SettingsActivity.AppPreferenceFragment().loadLocale();来实现目标，因此您的MainActivity将如下所示：

public class MainActivity extends AppCompatActivity {
//Some declarations
@Override
protected void onCreate(Bundle savedInstanceState) {

//I want to set my app language here by calling loadLocale()
AppPreferenceFragment appPreferenceFragment=(AppPreferenceFragment)getFragmentManager().findFragmentByTag("PreferenceFragment_MainActivity");
if(appPreferenceFragment==null)
appPreferenceFragment = new AppPreferenceFragment();
getFragmentManager()
.beginTransaction()
// have a hidden framelayout as flPrefContent in the XML file attached with this activity
.replace(R.id.flPrefContent, appPreferenceFragment, "PreferenceFragment_MainActivity")
.commit();
appPreferenceFragment.loadLocale();
//other code
}
}

但正如@najm在评论中建议的那样，您应该在可能的singleton类中提取这样的逻辑，并从应用程序中的任何位置使用该类的loadLocale()、setLocale()等方法，如MainActivity、SettingsActivity等。