小编Jos*_*ell的帖子

我正在使用选择器动态调用Objective-C中的函数.我的问题是,如果我传递一个不存在的函数名,我的@try/ @catchblock没有捕获异常.

在控制台中,我得到了一个未被捕获的NSInvalidArgumentException进一步下来,我得到了一个未被捕获NSException.

我试过在标准@try/ @catch块中捕获这两种类型的异常,但它们没有注册.如果我试图抓住NSInvalidArgumentException它,Xcode将不会让我编译,因为它不是一个公认的类型.

关于如何解决这个问题的任何想法？

@try {
    SEL s = NSSelectorFromString(@"funName");
    [self performSelector:s withObject: nil];
} 
@catch (NSException/NSInvalidArgumentException exception) {
     NSLog(@"ERROR: %@", [exception message/reason];
} 

如果用户在特定时间内没有触摸屏幕,我必须执行特定操作.我怎么能在Cocos2d中做到这一点？

一个非常基本的问题,当我有类似的东西:

 TTStyledText * text = [TTStyledText textFromXHTML:message.message lineBreaks:YES URLs:NO];
 text.width = self.frame.size.width - 60;
 text.font = [UIFont fontWithName:@"ArialMT" size:17.0];
 _main_title.text = text;

当我分配text时_main_title.text,是否意味着_main_title.text保留text？

有人可以通过循环显示如何检索值NSMutableArray吗？我的代码基本上为数组添加整数,如下所示:

NSMutableArray *ptr = [[NSMutableArray alloc] init];

[ptr addObject:[NSNumber numberWithInt:1]];
[ptr addObject:[NSNumber numberWithInt:2]];
[ptr addObject:[NSNumber numberWithInt:3]];

 // How to retrieve them as integers?

我正在尝试从数组中检索每个数字并将它们总计为总值.

[measureValue stringValue] 给了我这个例外:

由于未捕获的异常'NSInvalidArgumentException'而终止应用程序,原因:' - [NSCFString stringValue]:无法识别的选择器发送到实例0x4dde570'

[measureValue description] 工作得很好

但我想我应该stringValue在代码中使用,对吧？

这是代码:

NSNumber *measureValue = [NSString stringWithFormat:@"%i", [cellContent integerValue]];

//if imperial (inches)
if ([[[NSUserDefaults standardUserDefaults] stringForKey:@"Measure"] isEqualToString:@"Imperial"] ) {

    //if height
    if ([currentQuestion isEqualToString:@"Height"]) {
        measureValue = [NSNumber numberWithDouble:(2.54 * [measureValue doubleValue])];
    //elseif weight
    } else {
        measureValue = [NSNumber numberWithDouble:(0.45359237 * [measureValue doubleValue])];
    }

    //NSLog(@"%@", [measureValue stringValue]);
    cellContent = [measureValue description];

我在基类中有一个方法调用,如下所示:

#import <Foundation/Foundation.h>

@interface BaseController : NSObject

-(void)login;

@end

#import "BaseController.h"

@implementation BaseController

-(void)performTask
{
 return @"Base method loaded";
}


-(void)login
{
 [self performTask];
}


-(id)init
{
 if ((self = [super init]))
 {

 }

 return self;
}

-(void)dealloc
{
 [super dealloc];
}

@end

#import <Foundation/Foundation.h>
#import "BaseController.h"

@interface DerivedController : BaseController

-(void)performTask;

@end

#import "DerivedController.h"

@implementation DerivedController

-(void)performTask
{
 NSLog(@"Inherited method loaded.");
}

-(id)init
{
 if ((self = [super init])) { }

 return self;
}

-(void)dealloc
{
 [super dealloc];
} …

我正试图转变@"Fri, 26 Aug 2011 10:51:00 +02:00"为NSDate:

[dateFormatter setDateFormat:@"EEE, dd MMM yyyy HH:mm:ss Z"];
NSDate *date = [dateFormatter dateFromString:dateString];

我得到nil了结果; 我究竟做错了什么？

我有这段代码用于显示登录对话框/发布到用户墙:

_posting = YES;
// If we're not logged in, log in first...
if (![_session isConnected]) {
    self.loginDialog = nil;
    loginDialog = [[FBLoginDialog alloc] init]; 
    [_loginDialog show];
}
// If we have a session and a name, post to the wall!
else if (_facebookName != nil) {
    [self postToWall];
}
// Otherwise, we don't have a name yet, just wait for that to come through.

如果我将此代码连接到按钮,它可以工作.但是,当我将它放在以下方法中时:

- (void)alertView:(UIAlertView *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
    // the user clicked one of the OK/Cancel buttons …

我正在尝试UIWebView使用以下代码检查a中的当前URL :

- (void)webViewDidFinishLoad:(UIWebView *)webView {

    NSString *currentURL = webView.request.URL.absoluteString;

    NSLog(@"Current URL: %@", currentURL);

    NSString *loginpage = @"file:///var/mobile/Applications/652BAC0C-DEAE-4695-9195-BE617B9D5106/School%20VLE%20Business.app/login.html";

    if([currentURL isEqualToString:loginpage])
    {
        NSLog(@"Inputting user details...");

        NSString *result;
        result = [webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"$('#usernamefield').val('%@');", username]];
        result = [webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"$('#passwordfield').val('%@');", password]];
        result = [webView stringByEvaluatingJavaScriptFromString:@"$('#submitbutton').click();"];

        NSLog(@"Logged in!");

    }
}

但是本地URL(652BAC0C-DEAE-4695-9195-BE617B9D5106对我来说)中的代码对于每个人来说都不一样,所以我怎么能做同样的检查却没有长代码呢？

我正在尝试学习NSTimer,使用Foundation和打印到控制台.任何人都可以告诉我我需要做些什么来让以下工作？它编译没有错误,但不激活我的startTimer方法 - 没有打印.

我的目标是让一个方法调用另一个方法来运行一些语句,然后在设定的时间后停止.

#import <Foundation/Foundation.h>

@interface MyTime : NSObject {
    NSTimer *timer;
}
- (void)startTimer;
@end

@implementation MyTime

- (void)dealloc {
    [timer invalidate];
    [super dealloc];
}

- (void)startTimer {
     timer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(runTimer:) userInfo:nil repeats:YES];
}

- (void)runTimer:(NSTimer *)aTimer {
    NSLog(@"timer fired");
}
@end


int main(int argc, char *argv[]) {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];


    MyTime *timerTest = [[MyTime alloc] init];
    [timerTest startTimer];

    [timerTest release];

    [pool release];
    return 0;
}