Android Programming Application Setting global variables and example analysis of value-transfer usage _android

This article illustrates the application setting of global variables and the use of values for Android programming. Share to everyone for your reference, specific as follows:

/**
* Rewrite application, mainly rewrite the OnCreate method inside, that is, when created,
* We let it initialize some of the values that we saw in Javaeye some time ago, similar to this,
* I made some improvements. It is said that foreign developers are used to initializing some global variables, as if the
global variables are initialized in some classes of activity *, and some exceptions to null pointers will be encountered, of course, I have not encountered.
* If initialized with this method, you can avoid any errors that may occur.
* 
* Start Application, he will create a PID, is the process ID, all activity will run on this process.
* So we initialize the global variable when application is created, so all the activity can get these
* global variables, and further, we change the values of these global variables in one activity, So in other activity * is not the value of the
change, this calculation does not calculate the transfer value?
* OK, then the following example we test ...
* @author Yong.wang
* * */public
class MyApplication extends application {
  private String name ;
  @Override public
  void OnCreate () {
    super.oncreate ();
    SetName (NAME); Initialize global variable
  } public
  String GetName () {return
    name;
  }
  public void SetName (String name) {
    this.name = name;
  }
  private static final String NAME = "MyApplication";
}

OK, the application is created, but we should add the application MyApplication that will run in the configuration file Applicationmanifest.xml and modify it:

<?xml version= "1.0" encoding= "Utf-8"?> <manifest xmlns:android=
"http://schemas.android.com/apk/res/" Android "
  package=" Com.hisoft.app "
  android:versioncode=" 1 "
  android:versionname=" 1.0 ">
 < Application android:icon= "@drawable/icon" android:label= "@string/app_name" Android:name= "
     . MyApplication "> is here, the default application we used to set to him as our own myapplication
  <activity android:name=". Myfirstactivity "
     android:label=" @string/app_name ">
   <intent-filter>
    <action android: Name= "Android.intent.action.MAIN"/>
    <category android:name= "Android.intent.category.LAUNCHER"/>
   </intent-filter>
  </activity>
  <activity android:name= ". Mysecondactivity "></activity>
 </application>
 <uses-sdk android:minsdkversion=" 8 "/ >
</manifest>

When the XML configuration file runs out of Android:name=. MyApplication "", then the process ID is allocated, and below, we're going to run our activity.

public class Myfirstactivity extends activity {
  private MyApplication app;
 @Override public
 void OnCreate (Bundle savedinstancestate) {
  super.oncreate (savedinstancestate);
  Setcontentview (r.layout.main);
  App = (myapplication) getapplication (); Get our application MyApplication
  log.e ("Myfirstactivityoriginal", App.getname ())//Take the global variable we put into the process and see if it's the value we've set
  app.setname ("are cool");//ok, now we're starting to modify the
  LOG.E ("Myfirstactivitychanged", App.getname ()); Again, this value changes without
  Intent Intent = new Intent ();//More importantly, we can see if the value is initialized in the other activity or the modified
  Intent.setclass (this , mysecondactivity.class);
  StartActivity (intent);
 }

When it's done, we're going to jump to this activity.

public class Mysecondactivity extends activity {
  private MyApplication app;
  @Override
  protected void onCreate (Bundle savedinstancestate) {
    super.oncreate (savedinstancestate);
    Setcontentview (r.layout.main);
    App = (myapplication) getapplication (); Get Application
    log.e ("Mysecondactivity", App.getname ());//Get Global Value
  }  
}

OK, look at the value: Of course I've already run it.

Myfirstactivityoriginal MyApplication
Myfirstactivitychanged is cool
Mysecondactivity is cool

Look, is not particularly exciting, of course, you can quit after the run, the 2nd, 3 ... Times, it is possible that 3 outputs are all cool, which is the problem that you did not kill the process.

I hope this article will help you with the Android program.