检查活动是否是自启动以来的第一个活动

Question

我希望我的主要活动在启动时显示弹出窗口，此活动是创建的第一个活动，但可以创建此活动的多个实例，并且我只希望第一个活动启动显示这个弹出窗口，所以我想知道如果我可以检查这个。

Answer 1

做的最简单的方法是使用一个静态变量

你如何使用它：

定义静态布尔标志，并为其分配false值，一旦该活动首次创建，使标志真实的，现在你用简单的做你的任务if/else条件

public static boolean flag=false; 

然后在onCreate

if(flag==true) 
{ 
    //Activity is not calling for first time now 
} 

if(flag==false) 
{ 
    //first time calling activity 
     flag=true; 
} 

Answer 2

存储标志SharedPreferences表示应用程序是否第一次启动。使用Activity Oncreate方法为：

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    // Create and check SharedPreferences if fist time launch 
    SharedPreferences settings = getSharedPreferences("showpopup", 0); 
    SharedPreferences.Editor editor = settings.edit(); 

    if(settings.contains("firsttime")){ 
      // means activity not launched first time 
    }else{ 
     // means activity launched first time 
     //store value in SharedPreferences as true 
     editor.putBoolean("firsttime", true); 
     editor.commit(); 
      //show popup 
    } 
} 

Answer 3

我会使用selvins方法。除非你有一个后端应用程序设置和用户注册，也就没有办法，除非你使用SharedPreferences

int activityLaunchCount = 0; 

SharedPreferences preferences = getBaseContext().getSharedPreferences("MyPreferences", SharedPreferences.MODE_PRIVATE); 
activityLaunchCount = preferences.getInt("ActivityLaunchCount", 0); 

if(activityLaunchCount < 1) 
{ 
    // ** This is where you would launch you popup ** 
    // ...... 

    // Then you will want to do this: 
    // Get the SharedPreferences.Editor Object used to make changes to shared preferences 
    SharedPreferences.Editor editor = preferences.edit(); 

    // Then I would Increment this counter by 1, so if will never popup again. 
    activityLaunchCount += 1; 

    // Store the New Value 
    editor.putInt("ActivityLaunchCount", activityLaunchCount); 

    // You Must call this to make the changes 
    editor.commit(); 

}else{ 

// If you application is run one time, this will continue to execute each subsequent time. 
// TODO: Normal Behavior without showing a popup of some sort before proceeding. 

} 

然后，当你想关闭应用程序，为您获得此类信息的具体应用实例

Override的Activity完成（）方法

@Override public void finish() 
{ 
    super.finish(); 

    // Get the SharedPreferences.Editor Object used to make changes to shared preferences 
    SharedPreferences.Editor editor = preferences.edit(); 


    // Store the New Value 
    editor.putInt("ActivityLaunchCount", 0); 

    // You Must call this to make the changes 
    editor.commit(); 

}