Android authoritative Programming Guide-Notes (25th Chapter Search)

1. Searchview

Searchview is an operation view, the so-called Operation View, which is a view that can be built into the toolbar. Searchview allows the entire search interface to be fully built into the app's toolbar.

Configuration of the 1.1 Searchview

<?XML version= "1.0" encoding= "Utf-8"?><Menuxmlns:android= "Http://schemas.android.com/apk/res/android"Xmlns:app= "Http://schemas.android.com/apk/res-auto">    <ItemAndroid:id= "@+id/menu_item_search"Android:title= "@string/search"App:actionviewclass= "Android.support.v7.widget.SearchView"app:showasaction= "Ifroom" /></Menu>

APP:ACTIONVIEWCLASS Specifies the Android.support.v7.widget.SearchView value, telling the toolbar to display Searchview.

The menu XML file is then instantiated through the Oncreateoptionsmenu () method, so that the toolbar can display the options defined in the menu XML.

Use of 1.2 Searchview

The interface on which to instantiate and then set the callback.

MenuItem Searchitem = Menu.finditem (R.id.menu_item_search);//Remove the MenuItem and save it in the Searchitem variable. Msearchview = (Searchview) Searchitem.getactionview ();//Remove the Searchview object. //Setting up ListenersMsearchview.setonquerytextlistener (NewSearchview.onquerytextlistener () {@Override Public BooleanOnquerytextsubmit (String s) {//when you submit a search query. This method executes. LOG.D (TAG, "Onquerytextsubmit:" +s); return true; } @Override Public BooleanOnquerytextchange (String s) {//This method executes when the text of the search box changes. LOG.D (TAG, "Onquerytextchange:" +s); return false; }         });

2. Using shared preferences for lightweight data storage

Shared preferences is essentially a file in the file system and can be read and written using the Sharedpreferences class. The Sharedpreferences instance is more like a key-value pair warehouse (similar to Bundle), but it can persist data through persistent storage. The key in a key-value pair is a string, and the value is an atomic data type. Further viewing the shared preferences file, they are actually a simple XML file, but the Sharedpreferences class has masked the implementation details of the read-write file. The shared preferences file is saved in the app sandbox, so sensitive information like a password should not be saved with it.

To obtain a custom sharedpreferences instance, you can use the Context.getsharedpreferences (String,int) method. However, in actual development, we do not care about what the sharedpreferences instance is, as long as it can be shared throughout the application. In this case, it is best to use the Preferencemanager.getdefaultsharedpreferences (context) method, which returns an instance with a private permission and a default name (available only within the current app).

Shared Preference Example:

 Public classquerypreferences {Private Static FinalString pref_search_query = "SearchQuery";  Public StaticString Getstoredquery (context context) {returnPreferencemanager.getdefaultsharedpreferences (context). getString (Pref_search_query,NULL); }     Public Static voidSetstoredquery (context context, String query) {preferencemanager.getdefaultsharedpreferences (context). Edit (). P Utstring (Pref_search_query, QUERY). Apply ();
}}

Android authoritative Programming Guide-Notes (25th Chapter Search)