保存全局变量在appliation不管activty的转换

public class MyApplication extends Application {?
?
? ? private String someVariable;?
?
? ? public String getSomeVariable() {?
? ? ? ? return someVariable;?
? ? }?
?
? ? public void setSomeVariable(String someVariable) {?
? ? ? ? this.someVariable = someVariable;?
? ? }?
}?
<application android:name="MyApplication" android:icon="@drawable/icon" android:label="@string/app_name">?
// set?
((MyApplication) this.getApplication()).setSomeVariable("foo");?
?
// get?
String s = ((MyApplication) this.getApplication()).getSomeVariable();?