nsinvocation

Why does NSInvocation getReturnValue: lose object?

由 ￡可爱￡侵袭症＋ 提交于 2019-12-07 13:49:29
问题 I need your help. I have some problems with NSInvocation 'getReturnValue:' method. I want to create UIButton programmatically, and even more, I want to create it dynamically using NSInvocation and through passing value through the NSArray (that's why I wrapped UIButtonTypeRoundedRect). Listing. NSLog(@"Button 4 pushed\n");//this code executed when button pushed Class cls = NSClassFromString(@"UIButton");//if exists {define class},else cls=nil SEL msel = @selector(buttonWithType:); //id

What's the difference between NSInvocation and block?

由 依然范特西╮ 提交于 2019-12-07 06:43:06
问题 when i say block i mean: ^(int a) {return a*a;}; besides, block is only support by iOS4 and above. What is the difference between these two? 回答1: An NSInvocation is a message (using a selector) to an object, with optional parameters, which can be executed later (or now), and outside the current context (mind of course what you copy vs retain or reference if you move it). NSInvocation has the benefit that you can selectively copy/refer to exactly what you need. The block is a secret local

NSInvocation & NSError - __autoreleasing & memory crasher

由 我与影子孤独终老i 提交于 2019-12-06 04:43:20
问题 In learning about NSInvocations it seems like I've got a gap in my understanding about memory management. Here is a sample project: @interface DoNothing : NSObject @property (nonatomic, strong) NSInvocation *invocation; @end @implementation DoNothing @synthesize invocation = _invocation; NSString *path = @"/Volumes/Macintosh HD/Users/developer/Desktop/string.txt"; - (id)init { self = [super init]; if (self) { SEL selector = @selector(stringWithContentsOfFile:encoding:error:); NSInvocation *i

Accessing forwardInvocation'd methods with ARC?

由 隐身守侯 提交于 2019-12-05 04:23:06
问题 I'm writing a clone of OpenStruct in Objective-C, using forwardInvocation:. However, the compiler isn't aware of the forwarding at compile time apparently. Compiling with ARC gives me a ton of warnings. The code is open source and available on Github, but is currently compiled with -fno-objc-arc. If anyone could take a look at how I could make this ARC compatible, I'd greatly appreciate it. 回答1: I tried this code: OpenStruct *myStruct = [[OpenStruct alloc] initWithDictionary:myDictionary];

How to remove/cancel NSInvocationOperation from NSOperationQueue?

由 二次信任 提交于 2019-12-03 17:33:52
Both of the following questions are being asked in context to maintain NSOperationQueue and NSInvocationOperation. As I have used this concept to download multiple videos, how do I remove/release added NSInvocationOperation from NSOperationQueue after completion of downloading a video? And also, what should I do if in case I want to stop to download specific video while the process of downloading in progress? how do I remove/release added NSInvocationOperation from NSOperationQueue after completion of downloading a video? The operation is automatically removed from the queue when it has

NSInvocation getReturnValue: called inside forwardInvocation: makes the returned object call dealloc:

由 南楼画角 提交于 2019-12-03 15:05:56
Here's a standalone test.m file that I'm using to test the behavior. To compile: clang test.m -o test.app -fobjc-arc -ObjC -framework Foundation . Make sure the Xcode command-line tools are installed. #import <Foundation/Foundation.h> @protocol Protocol @optional - (id)objProxyMethod; @end @interface ReturnObject: NSObject @end @interface Test : NSObject <Protocol> @end @interface Proxy : NSObject <Protocol> - (id)objProxyMethod; @end @implementation ReturnObject - (void)dealloc { NSLog(@"ERROR:"); NSLog(@"I'm getting deallocated!"); NSLog(@"This shouldn't happen!"); } - (NSString *

-[NSInvocation getReturnValue:] with double value produces 0 unexpectedly

由 半世苍凉 提交于 2019-12-03 11:40:35
问题 I am trying to call a method that returns a double using NSInvocation . But I found that it does not working in 64 bit iOS apps. It works on on OS X, in the simulator -- both 32-bit and 64 bit -- iPad 2, and iPad Air with a 32-bit build. Only the 64-bit build on an iPad Air device has this problem. This is the code to demo the problem: NSMethodSignature *signature = [NSString instanceMethodSignatureForSelector:@selector(doubleValue)]; for (int i = 0; i < 10; i++) { NSInvocation *invocation =

-[NSInvocation getReturnValue:] with double value produces 0 unexpectedly

由 我怕爱的太早我们不能终老 提交于 2019-12-03 02:12:07
I am trying to call a method that returns a double using NSInvocation . But I found that it does not working in 64 bit iOS apps. It works on on OS X, in the simulator -- both 32-bit and 64 bit -- iPad 2, and iPad Air with a 32-bit build. Only the 64-bit build on an iPad Air device has this problem. This is the code to demo the problem: NSMethodSignature *signature = [NSString instanceMethodSignatureForSelector:@selector(doubleValue)]; for (int i = 0; i < 10; i++) { NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature]; NSString *str = [NSString stringWithFormat:@"%d

Invoke block iOS

由 血红的双手。 提交于 2019-11-30 15:49:02
问题 I try to invoke some block, but I run into a EXC_BAD_ACCESS. -(void) methodA { self.block = ^ { [self methodB]; }; } -(void) webViewDidFinishLoad:(UIWebView *)webView { [block invoke]; // error here (block is not valid id type). } -(void)methodB { //do something } Any thoughts on why this is happening? 回答1: You should use copy attribute when you are declaring block property. Like: @property (nonatomic, copy) id block; 回答2: if you want to invoke the block you can simply do this block();

NSInvocation returns value but makes app crash with EXC_BAD_ACCESS

由 随声附和 提交于 2019-11-30 11:03:55
问题 I have an array which I am iterating and looking for a particular flag. If the flag value is nil, I am calling a method which generates an invocation object and returns the result of invocation. My code structure is as follows for(NSString *key in [taxiPlanes allKeys]) { Plane *currentPlane = [taxiPlanes objectForKey:key]; if(currentPlane.currentAction == nil) { NSString *selector = [[currentPlane planeTakeoffSequence] firstObject]; currentPlane.currentAction = selector; // Calling for
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