android sdk 退出机制的研究 有多种,
方法一、用list保存activity实例,然后逐一干掉
上代码:
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<Activity> mList = new LinkedList<Activity>();
private static SysApplication instance;
private SysApplication() {
}
public synchronized static SysApplication getInstance() {
if (null == instance) {
instance = new SysApplication();
}
return instance;
}
// add Activity
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);
}
}
@Override
public void onLowMemory() {
super.onLowMemory();
System.gc();
}
}
在每个Activity的onCreate方法中添加类似代码:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SysApplication.getInstance().addActivity(this);
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SysApplication.getInstance().addActivity(this);
}
在需要退出程序的时候,调用:
SysApplication.getInstance().exit();
SysApplication.getInstance().exit();
简而言之,通过单例模式把每个Activity 的引用添加到一个全局链表中,每次退出程序调用System.exit(0)时,先调用链表中Activity 的finish方法
方法二、使用广播
ActivityManager manager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
manager.killBackgroundProcesses(package);
不行
android.os.Process.killProcess(android.os.Process.myPid());
也不行
manager.restartPackage(package);
还是不行
Intent MyIntent = new Intent(Intent.ACTION_MAIN);
MyIntent.addCategory(Intent.CATEGORY_HOME);
startActivity(MyIntent);
finish();
这个只是退回到桌面,如果打开多个Activity关闭重新打开也会有问题,还是还是不行
看到有说广播机制,发现是个好东东,能彻底解决这个问题,废话不说看代码:
public abstract class EnterActivity extends BaseActivity {
...
// 写一个广播的内部类,当收到动作时,结束activity
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
unregisterReceiver(this); // 这句话必须要写要不会报错,不写虽然能关闭,会报一堆错
((Activity) context).finish();
}
};
@Override
public void onResume() {
super.onResume();
// 在当前的activity中注册广播
IntentFilter filter = new IntentFilter();
filter.addAction(Attribute.PAGENAME);
registerReceiver(this.broadcastReceiver, filter); // 注册
}
/**
* 关闭
*/
public void close() {
Intent intent = new Intent();
intent.setAction(Attribute.PAGENAME); // 说明动作
sendBroadcast(intent);// 该函数用于发送广播
finish();
}
...
}
这就是 我对android中的activity的退出机制的总结.
在以后的教程中,我们将一步步实现这样的效果.