Android之Application
android编程中,application这样的名词似乎变得那样的不常见,而让大家更为熟悉的是activity、intent、provider、broadcast和service。但其实android中的application也有着它自身的用处。打开manifest文件,会看到有一个application配置标签,这就是有关application的使用了。
就是说application是用来保存全局变量的,并且是在package创建的时候就跟着存在了。所以当我们需要创建全局变量的时候,不需要再像j2se那样需要创建public权限的static变量,而直接在application中去实现。只需要调用Context的 getApplicationContext或者Activity的getApplication方法来获得一个application对象,再做出相应的处理。
application文件:
Java代码:
1. public class TestApplication extends Application {
2. private int curIndex;
3. public int getCurIndex() {
4. return curIndex;
5. }
6. public void setCurIndex(int curIndex) {
7. this.curIndex = curIndex;
8. }
9. @Override
10. public void onCreate() {
11. super.onCreate();
12. }
13. @Override
14. public void onTerminate() {
15. super.onTerminate();
16. }
17. }
18. public class TestApplication extends Application {
19. private int curIndex;
20. public int getCurIndex() {
21. return curIndex;
22. }
23. public void setCurIndex(int curIndex) {
24. this.curIndex = curIndex;
25. }
26. @Override
27. public void onCreate() {
28. super.onCreate();
29. }
30. @Override
31. public void onTerminate() {
32. super.onTerminate();
33. }
34. }
第二个Activity:
1. TestApplication application = (TestApplication)this.getApplication();
2. Log.i("data", ""+application.getCurIndex());
3. application.setCurIndex(6);
4. TestApplication application = (TestApplication)this.getApplication();
5. Log.i("data", ""+application.getCurIndex());
6. application.setCurIndex(6);
application中有一个curIndex和settergetter方法。
第一个acitivty中对application进行的操作:
Java代码:
1. TestApplication application = (TestApplication) this.getApplication();
2. Log.i("data", ""+application.getCurIndex());
3. application.setCurIndex(5);
4. TestApplication application = (TestApplication) this.getApplication();
5. Log.i("data", ""+application.getCurIndex());
6. application.setCurIndex(5);
第三个Activity:
1. final TestApplication application = (TestApplication) this.getApplication();
2.
3. Log.i("data", ""+application.getCurIndex());
4. final TestApplication application = (TestApplication) this.getApplication();
5. Log.i("data", ""+application.getCurIndex());
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