Android活动生命周期

活动1通过单击按钮启动活动2。一旦Activity 2的静态内容被设置并显示给用户，我想启动一个AsyncTask。在执行AsyncTask时，ProgressBar应显示给用户。我的问题是，在活动2关注之后，活动1不会在ProgressBar发生时发生，活动1在AsyncTask执行时保持可见状态，然后在执行完成后切换到活动2。我试图把我的AsyncTask在：Android活动生命周期

的OnCreate
OnPostCreate
的OnStart
的onResume

...活动2，但活动还是2只变成一次可见任务执行完成。在活动2的生命周期中，我需要放置我的AsyncTask以实现我想要的功能？如果你需要它的代码：

活动1开始的的AsyncTask前进之前验证用户的输入。在该任务的OnPostExecute，如果信息是有效的：

Intent intent = new Intent(_context, typeof(Activity2)); 
intent.PutExtra("Call", _call); 
intent.PutExtra("Site", _site); 
intent.PutExtra("ServiceType", _serviceType); 
intent.PutExtra("Priority", _priority); 
_context.StartActivity(intent);

Activity2.cs

public class Activity2 : Activity 
{ 
    private string Call { get; set; } 
    private string Site { get; set; } 
    private string Priority { get; set; } 
    private string ServiceType { get; set; } 
    private ViewAnimator Animator { get; set; } 
    private Spinner PrioritySpin { get; set; } 
    private Spinner ProblemSpin { get; set; } 
    private Spinner CauseSpin { get; set; } 
    private Spinner RepairSpin { get; set; } 
    private Spinner LaborHrsSpin { get; set; } 
    private Spinner LaborDecSpin { get; set; } 
    private Spinner TravelHrsSpin { get; set; } 
    private Spinner TravelDecSpin { get; set; } 
    private Spinner SerlModelSpin { get; set; } 

    protected override void OnCreate(Bundle bundle) 
    { 
     base.OnCreate(bundle); 

     Intent intent = Intent; 
     Call = intent.GetStringExtra("Call"); 
     Site = intent.GetStringExtra("Site"); 
     Priority = intent.GetStringExtra("Priority"); 
     ServiceType = intent.GetStringExtra("ServiceType"); 

     Title = "Service Report for Call #" + Call + " at Site " + Site; 

     SetContentView(Resource.Layout.Activity2); 

     Animator = (ViewAnimator) FindViewById(Resource.Id.contentContainer); 

     Button basic = (Button) FindViewById(Resource.Id.basicBtn); 
      basic.Click += WizardClick; 
     Button equipment = (Button) FindViewById(Resource.Id.equipmentBtn); 
      equipment.Click += WizardClick; 
     Button parts = (Button) FindViewById(Resource.Id.partsBtn); 
      parts.Click += WizardClick; 
     Button comments = (Button) FindViewById(Resource.Id.commentsBtn); 
      comments.Click += WizardClick; 
     Button review = (Button) FindViewById(Resource.Id.reviewSubmit); 
      review.Click += WizardClick; 

     PrioritySpin = (Spinner) FindViewById(Resource.Id.prioritySpinner); 
     ProblemSpin = (Spinner) FindViewById(Resource.Id.problemSpinner); 
     CauseSpin = (Spinner) FindViewById(Resource.Id.causeSpinner); 
     RepairSpin = (Spinner) FindViewById(Resource.Id.repairSpinner); 
     LaborHrsSpin = (Spinner) FindViewById(Resource.Id.laborHrsSpinner); 
     LaborDecSpin = (Spinner) FindViewById(Resource.Id.laborDecSpinner); 
     TravelHrsSpin = (Spinner) FindViewById(Resource.Id.travelHrsSpinner); 
     TravelDecSpin = (Spinner) FindViewById(Resource.Id.travelDecSpinner); 

     ArrayAdapter<string> priorityAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, Priorities()); 
     ArrayAdapter<string> problemAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, Problems()); 
     ArrayAdapter<string> causeAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, Cause()); 
     ArrayAdapter<string> repairAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, Repair()); 
     ArrayAdapter<string> hoursAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, Hours()); 
     ArrayAdapter<string> decAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, QuarterHours()); 

     PrioritySpin.Adapter = priorityAdapter; 
     ProblemSpin.Adapter = problemAdapter; 
     CauseSpin.Adapter = causeAdapter; 
     RepairSpin.Adapter = repairAdapter; 
     LaborHrsSpin.Adapter = hoursAdapter; 
     LaborDecSpin.Adapter = decAdapter; 
     TravelHrsSpin.Adapter = hoursAdapter; 
     TravelDecSpin.Adapter = decAdapter; 

     PrioritySpin.SetSelection(Convert.ToInt32(Priority)); 

     if (ServiceType == "PM") 
     { 
      ProblemSpin.SetSelection(Array.IndexOf(Problems(), "Scheduled")); 
      CauseSpin.SetSelection(Array.IndexOf(Cause(), "Scheduled")); 
     } 

     Window.SetSoftInputMode(SoftInput.StateAlwaysHidden); 
    } 

    protected override void OnResume() 
    { 
     base.OnResume(); 

     SerlModelSpin = (Spinner)FindViewById(Resource.Id.equipSpinner); 

     IEquipment equipInterface = new EquipmentHelper(this, Animator, 5, 0); 
     string[] equipList = equipInterface.GetEquipmentList(Site); 
     ArrayAdapter<string> equipAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleSpinnerDropDownItem, equipList); 

     SerlModelSpin.Adapter = equipAdapter; 
    } 
}

来源

2012-07-11 jmease

AsyncTask是怎么样的？请记住在实际的UI线程上更新UI事物。活动生命周期可以在这里看到：https://developer.android.com/reference/android/app/Activity.html – Cheesebaron 2012-07-12 19:32:35

http://stackoverflow.com/a/8516056/265167 – 2013-01-10 11:22:24

为什么重要的活动，两个人在后台，而这是的AsyncTask在后台运行？不管...为什么不在AsyncTask中放置一个标志，并等待设置标志并显示对话框，直到onResume()方法完成执行。或者，您可以尝试在活动时从活动一中调用静态启动方法。也许通过调用finish（）然后重写onDestroy（）方法。它很难得到那个时间。

来源

2012-07-12 20:55:46 Joel

Android活动生命周期

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