Language switch in SAPUI5

问题:

I've got a language problem with my SAPUI5 controls.

If I execute e.g.:

sap.ui.getCore().getConfiguration().setLanguage( "de" );

My i18n files are loaded correctly and all labels are translated to German. But the controls are still in English.

The only way to get German controls is with the url parameter:

sap-ui-language=DE

But I can't use a parameter in my case. Any idea?

回答1:

Please note that sap.ui.getCore().setLanguage() explicitly states

The framework does not guarantee that already created, language dependent objects will be updated by this call. It therefore remains best practice for applications to switch the language early, e.g. before any language dependent objects are created. Applications that need to support more dynamic changes of the language should listen to the localizationChanged event and adapt all language dependent objects that they use (e.g. by rebuilding their UI).

Besides that, I fully support Nabi's answer (but I'm not allowed to vote it up).

I just would like to add that controls (like FilterBar) better should use the hook approach:

FilterBar.prototype.onlocalizationChanged = function(oEvent) {
  // .. same bundle update code as in Nabi's proposal
}

Using the hook in controls avoids the need for adding attach + detach calls in init / exit and keeps the event registry small.

回答2:

I can easily confirm the behavior you described by testing the Explored App Example. There, just open the console and hit sap.ui.getCore().getConfiguration().setLanguage("de");

I also checked the implementation of the FacetFilter and I would call this a bug in the Control implementation. It comes from how the texts are loaded inside the control. Just in case you are interested:

1. The message bundles all contain the correct translations for FACETFILTER_INFOBAR_NO_FILTERS (for en the translation comes from the "default" bundle):

   • messagebundle.properties
   • messagebundle_de.properties

2. The FacetFilter has a hidden aggregation called SummaryBar. The SummaryBar contains the text you see. Of course, this text comes from a bundle.

3. However, the bundle is initialized exactly once in init() by calling sap.ui.getCore().getLibraryResourceBundle("sap.m");. Here the API docs say:

   If only one argument is given, it is assumed to be the libraryName. The locale then falls back to the current session locale.

4. This means the bundle is cached and therefor changes to the localization (e.g. language) do not trigger the bundle to load a new translation file. Thus, we will always see the initial language no matter what we try (even rerendering() does not help).

A solution would be to fix the control by adding the following code right after the the bundle gets loaded inside the init:

sap.ui.getCore().attachLocalizationChanged(function(oEvent){
    var oChanges = oEvent.getParameter("changes");    
    if (oChanges && oChanges.language){
        this._bundle = sap.ui.getCore().getLibraryResourceBundle("sap.m", oChanges.language);
        this.rerender();
    }
}.bind(this));

You can try this out in the explored app linked above, it worked for me just fine...

I just opened an issue on github.