Android Development-Application class

This digest is from Google's Android website translation, if there is wrong place, please the Great God Guidance

Website: http://developer.android.com/reference/android/app/Application.html

Application,activity,service,content provider are all system components of the Android framework, and when the Android program starts, a Application object is created to store some information about the system.

Launching an Android application is tantamount to starting a process where a process has only one Application object

Well, before Activity,service,broadcast,content provider, it was application.

So application belongs to a singleton pattern.

Sometimes we need to do some initialization on the custom application.

<span style= "FONT-SIZE:14PX;" >public class MyApplication extends application{    private static final String URL = "Http://api.demo.com/login"; C1/>private String value;        @Override public    void OnCreate ()    {        super.oncreate ();        SetValue (VALUE); Initialize global variable    } public        void SetValue (String value)    {        this.value = value;    }        Public String GetValue ()    {        return value;    }} </span>

We can set and get this URL in activity,service,broadcast,content provider.

Of course there are nine other methods of this class that we can rewrite.

onCreate () called when application is created

onlowmemory () The memory consumed by the application process is eliminated when the entire system is low on memory

registeractivitylifecyclecallbacks ( application.activitylifecyclecallbacks callback)

            Register activity lifecycle callback

registercomponentcallbacks ( componentcallbacks callback)

            Register component callbacks

registeronprovideassistdatalistener ( application.onprovideassistdatalistener callback)

            Registration data persistence is called, that is, the commonly said cache

unregisteractivitylifecyclecallbacks ( application.activitylifecyclecallbacks callback)

            Unregister the activity lifecycle callback

unregistercomponentcallbacks ( componentcallbacks callback)

            Unregister component callbacks

unregisteronprovideassistdatalistener ( application.onprovideassistdatalistener callback)

Unregister data Persistence

Android Development-Application class