我們在寫android應用程序時,經常會遇到想退出當前Acitivity,或者直接退出應用程序.我之前的一般操作是按返回鍵,或者直接按home鍵直接返回,其實這兩種操作都沒有關閉當前應用程序,沒有釋放系統資源。有時跳轉的activity較多時,還需要多次按返回鍵,這樣感覺一點都不爽。安卓如何一鍵退出應用。
后面添加了一個菜單返回功能鍵,這個方法也只能用system.exit(0)來關閉當前活動的Activity,附代碼:
- public?boolean?onCreateOptionsMenu(Menu?menu)??
- {??
- ??
- super.onCreateOptionsMenu(menu);??
- MenuItem?item?=?menu.add(Menu.NONE,?Menu.NONE,?Menu.NONE,?"Exit");??
- item.setOnMenuItemClickListener(new?MenuItem.OnMenuItemClickListener()??
- {??
- public?boolean?onMenuItemClick(MenuItem?item)??
- {??
- System.exit(0);??
- return?true;??
- }??
- });??
- return?true;??
- }??
想到這樣太不方便了,每次退出界面之后應用程序還在運行,今天查了下資料終于把這個問題給解決了,
網上提供了幾種方法,我吸收了下面這個自認為簡單易懂的方法,將下面SysApplication這個類復制到工程里面,然后在每個Acitivity的oncreate方法里面通過SysApplication.getInstance().addActivity(this);?添加當前Acitivity到ancivitylist里面去,最后在想退出的時候調用
SysApplication.getInstance().exit();可直接關閉所有的Acitivity并退出應用程序。
附代碼:
- import?java.util.LinkedList;???
- import?java.util.List;???
- import?android.app.Activity;???
- import?android.app.AlertDialog;???
- import?android.app.Application;???
- import?android.content.DialogInterface;???
- import?android.content.Intent;???
- ???
- public?class?SysApplication?extends?Application?{???
- ????private?List?mList?=?new?LinkedList();???
- ????private?static?SysApplication?instance;???
- ???
- ????private?SysApplication()?{?????
- ????}???
- ????public?synchronized?static?SysApplication?getInstance()?{???
- ????????if?(null?==?instance)?{???
- ????????????instance?=?new?SysApplication();???
- ????????}???
- ????????return?instance;???
- ????}???
- ??????
- ????public?void?addActivity(Activity?activity)?{???
- ????????mList.add(activity);???
- ????}???
- ???
- ????public?void?exit()?{???
- ????????try?{???
- ????????????for?(Activity?activity?:?mList)?{???
- ????????????????if?(activity?!=?null)???
- ????????????????????activity.finish();???
- ????????????}???
- ????????}?catch?(Exception?e)?{???
- ????????????e.printStackTrace();???
- ????????}?finally?{???
- ????????????System.exit(0);???
- ????????}???
- ????}???
- ????public?void?onLowMemory()?{???
- ????????super.onLowMemory();???????
- ????????System.gc();???
- ????}????
- }??
在應用程序里面 的activity的oncreate里面添加SysApplication.getInstance().addActivity(this)
如:
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
SysApplication.getInstance().addActivity(this);?
}