检测Activity是否在当前Task的栈顶

检测Activity是否在当前Task的栈顶

2012-03-13 23:38 311人阅读 评论(3) 收藏 举报

 

 

Android系统内部状态信息的相关api：

得到ActivityManager ：

ActivityManager activityManager = (ActivityManager)this.getSystemService(ACTIVITY_SERVICE)

这个位查到底是什么信息：   

ConfigurationInfo configurationInfo = activityManager.getDeviceConfigurationInfo();  

获取进程内存状态的信息：

Debug.MemoryInfo[] processMemoryInfo = activityManager.getProcessMemoryInfo(processIds);

  

获取当前运行的service信息：

List<RunningServiceInfo> runningServiceInfos = activityManager.getRunningServices(MaxValue);   

获取当前运行的任务信息：
List<RunningTaskInfo> runningTaskInfos = activityManager.getRunningTasks(MaxValue);
其中runningTaskInfos 的 topActivity就是当前Task的活跃Activity
在getRunningTasks()所返回的Task队列中系统会根据这些Task的活跃度有一个排序，越活跃越是靠前。第一个就是当前活动的Task

/**

* 检测某ActivityUpdate是否在当前Task的栈顶

*/

public boolean isTopActivy(String cmdName){
        ActivityManager manager = (ActivityManager) context.getSystemService(ACTIVITY_SERVICE);
        List<RunningTaskInfo> runningTaskInfos = manager.getRunningTasks(1);
        String cmpNameTemp = null;

        if(null != runningTaskInfos){

                cmpNameTemp=(runningTaskInfos.get(0).topActivity).toString);

                Log.e("cmpname","cmpname:"+cmpName);

        }

       if(null == cmpNameTemp)return false;
       return cmpNameTemp.equals(cmdName);

}

最后在应用中添加所需的权限：

<uses-permission android:name="android.permission.GET_TASKS"/>

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3楼 lideguo1979 2012-03-13 23:59发表 [回复]

多层Activity嵌套时，获取Context对象方法
public static Context getDialogContext(Activity act) {
Context context;
if (act.getParent() != null)
context = act.getParent();
else
context = act;
return context;
}
//三层嵌套
public static Context getDialogContext3(Activity act) {
Context context;
if (act.getParent().getParent() != null) {
context = act.getParent().getParent();
} else if (act.getParent() != null)
context = act.getParent();
else
context = act;
return context;
}

2楼 lideguo1979 2012-03-13 23:52发表 [回复]

try {
Activity a = (Activity) (Class.forName(component.getClassName()).newInstance());
Log.i(tag,a.getClass().toString());

} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

1楼 lideguo1979 2012-03-13 23:52发表 [回复]

public class RunningActivity extends Activity {
private static final String tag = "RunningActivity";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);


ActivityManager am= (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);

List<RunningTaskInfo> runningTasks = am.getRunningTasks(1);

RunningTaskInfo rti = runningTasks.get(0);
ComponentName component = rti.topActivity;

Log.i(tag, component.getClassName());
}
}

<uses-permission android:name="android.permission.GET_TASKS"></uses-permission>