retain

问题 I have the following data and used one of the existing answered questions to solve my data problem but could not get what I want. Here is what I have in my data Amt1 is populated when the Evt_type is Fee Amt2 is populated when the Evt_type is REF1/REF2 I don't want to display any observations after the last Flag='Y' If there is no Flag='Y' then I want all the observations for that id (e.g. id=102) I want to display if the next row for that id is a Fee followed by REF1/REF2 after flag='Y' (e.g

问题 I have the following data and used one of the existing answered questions to solve my data problem but could not get what I want. Here is what I have in my data Amt1 is populated when the Evt_type is Fee Amt2 is populated when the Evt_type is REF1/REF2 I don't want to display any observations after the last Flag='Y' If there is no Flag='Y' then I want all the observations for that id (e.g. id=102) I want to display if the next row for that id is a Fee followed by REF1/REF2 after flag='Y' (e.g

问题 Can I detect whether the Fragment I am going to call is already called or created so that I can reuse it instead of recreating it? 回答1: The fragments have isVisible() method . if(fragment.isVisible()){ //your code.// } By this you can see if the fragment is already created or not. 回答2: Test if onCreateView has been called public abstract class SubFragment extends Fragment { protected boolean onCreateViewCalled = false; public boolean hasOnCreateViewBeenCalled() { return onCreateViewCalled; }

问题 I'm new to Objective-C, I try to port an old Objective-C project written in an older version of Objective-C to the new one, but I'm getting the following compiler error: ARC forbids explicit message send of 'retain' in color = [aColor retain]; or color = [[NSColor blackColor] retain]; I was reading about the new automatic reference counting that clang is using now. I have also tried to use Xcode's refactor function but with no luck... What is the proper Objective-C code that need to replace

问题 A 101 question Let's say i'm making database of cars and each car object is defined as: #import <UIKit/UIKit.h> @interface Car:NSObject{ NSString *name; } @property(nonatomic, retain) NSString *name; Why is it @property(nonatomic, retain) NSString *name; and not @property(nonatomic, assign) NSString *name; ? I understand that assign will not increment the reference counter as retain will do. But why use retain , since name is a member of the todo object the scope of it is to itself. No other

问题 What does @propert(retain) do? it doesn't actually retain my object by my tests: id obj = getObjectSomehow(); NSLog(@"%d", [obj retainCount]); propertyWithRetain = obj; NSLog(@"%d", [obj retainCount]); // output: // 1 // 1 How can I make a property that will really retain the object? 回答1: You're not using your property there, that's why it's not retaining! Try this : id obj = getObjectSomehow(); NSLog(@"%d", [obj retainCount]); self.propertyWithRetain = obj; // Note the self. :) NSLog(@"%d",

问题 We are using spring security for the authentication in our application. The login form has four parameters (four input text fields for username, organization, company and password). When wrong password is entered all the other input parameters are also cleared from the login form. How do we retain those values? We do not want user to enter the other details again if the authentication fails. 回答1: Are you using Spring MVC? If so it is very easy to do that if you use the spring form tags in jsp

问题 We are using spring security for the authentication in our application. The login form has four parameters (four input text fields for username, organization, company and password). When wrong password is entered all the other input parameters are also cleared from the login form. How do we retain those values? We do not want user to enter the other details again if the authentication fails. 回答1: Are you using Spring MVC? If so it is very easy to do that if you use the spring form tags in jsp

问题 so the story goes like this :) i am trying to block enumerate objects in an NSArray and dynamically create UITableViews for each of them and add them in UIScrollView. i am using Lighter View Controllers from www.objc.io for the sake of readability and reusability. the dataSource gets created for each UITableView separately. the problem is i crash all the time with -[NSObject(NSObject) doesNotRecognizeSelector:] i found out from posts on stack that objects in block enumeration are weak

问题 I have started working more with delegate as suggested in another question I made. Now, I have made a UIViewController called ProfileViewController in which I would like to load the News Feed from Facebook. I also have subclass of NSObject called FBFeed . This subclass loads the Facebook News Feed and should pass it back to the view controller. All my requests to Facebook are sent through a singleton named FBRequestWrapper which (in this case) should pass the result to FBFeed . I call