lifecycle

问题 here is the code that can reproduce this issue: @Controller public class FirstController { @RequestMapping(value = "firstpage", method = GET) public String myHander(HttpSession httpSession) { if (httpSession.getAttribute("someClass") == null) { httpSession.setAttribute("someClass", new SomeClass()); } return "firstpage"; } } the first controller puts something in the session if it's not already there. @Controller @SessionAttributes(types = SomeClass.class) public class SecondController {

问题 In a UIViewController subclass, I have the following methods: -(void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; // do something myTextField.text = @"Default"; } - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; // do something [myTextField selectAll:self]; [myTextField becomeFirstResponder]; } - (void)viewDidLoad { [super viewDidLoad]; // do something myTextField.delegate = self; } The NIB has been created using Interface Builder. The corresponding

问题 i have made changes in navigation bar means i have increasd the height of navigation bar & made some custom changes,it works fine but when i minimizes the application and again maximize it, it shows only original height that is what changes i made, those not works after minimization, my code is - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { NSLog(@" i m in didFinishLaunchingWithOptions" ); [[UINavigationBar appearance]

问题 Do fields need to be initialized using the constructor for angular components? A lot of angular tutorials do: counter: number; constructor() { this.counter = 1; } Instead of just counter: number = 1 . 回答1: Both are correct programming wise, Initialized within the constructor It would be good practice to initialized within the constructor , it's kind of code separation of declaration + initialization . That will increase your code readability and you will be sure that all values initialized

问题 I just put log tags on most activity and fragment methods and this is the result: 06-19 16:33:11.934: I/Fragment Activity:MainMenuPager(15820): onCreate - BEGIN 06-19 16:33:11.958: I/Fragment Activity:MainMenuPager(15820): onCreate - END 06-19 16:33:11.958: I/Fragment Activity:MainMenuPager(15820): onStart - BEGIN 06-19 16:33:11.958: I/Fragment Activity:MainMenuPager(15820): onStart - END 06-19 16:33:11.958: I/Fragment Activity:MainMenuPager(15820): onResume - BEGIN 06-19 16:33:11.958: I

问题 I have a singleInstance Activity and a Fragment which I instantiate in the onCreate() method and add into a FrameLayout container into the layout of the activity. The activity does nothing except printing out the logs. I am using the android-support-v4 lib and android 2.3.3. I observed a strange lifecycle behavior with this setting and I wonder if you might help me to explain this. I will provide the logs for the lifecycles: First call of the activity: 07-07 15:12:17.990 V/FragActivity( 2358)

问题 This question already has answers here : Closed 6 years ago . Possible Duplicate: Android Activity Life Cycle - What are all these methods for? I have an activity which is main called menuActivity and another activity which called birthDate . When I run the application the menuActivity become the active one and when I click on a button the second one become the active one which is the birthDate . My question is: When the first activity become active another activity goes to background and

问题 I wonder at what point one would call activateSession() on a WCSession object on the watch and on the iOS device. In the documentation it says: Always assign a delegate and activate your session before calling any session-related methods. The session must be configured and activated before sending messages or obtaining information about the state of the connection. At first thought I put my code to initialise the session: if (WCSession.isSupported()) { session = WCSession.defaultSession()

问题 Suppose I have two screens: Screen A Screen B I am initially landed on Screen A . When I click on a Button I navigate to Screen B . When I press Back Button , I am again navigated to Screen A . I want to call an action creator when I am navigated to Screen A as mentioned in above scenario. I just want to know that which lifecycle event will be called every time when a screen is presented. Isn't there some event like componentWillAppear() ? Note: I am using react-native with react-navigation

问题 I have some JUnit tests that use the TemporaryFolder @Rule . They use the TemporaryFolder in a @Before method to perform some setup: @Rule public TemporaryFolder folder = new TemporaryFolder(); @Before public void init() { folder.newFile("my-file.txt"); } @Test public void myTest() { ... } Most of the time this works perfectly. However, when using the SpringJUnit4ClassRunner I find that in some cases the init() method is invoked before the Statement inside my TemporaryFolder instance is