Cocoa：Cocoa Snippets 01-10

1. Open URL in Safari

NSURL *url = [ [ NSURLalloc ] initWithString: @"http://www.cnn.com" ];

[[UIApplication sharedApplication] openURL:url];

2. Date Formatting on iPhone and Cocoa

//Format Date

NSDateFormatter *dateFormat = [[NSDateFormatteralloc] init];

[dateFormat setDateFormat: @"yyyy-MM-dd HH:mm:ss zzz"]; // 2009-02-01 19:50:41 PST

NSString *dateString = [dateFormat stringFromDate : [ scoreData objectForKey : @"date" ]];

3. Get iPhone Application Version Number

NSString *version = [[[NSBundlemainBundle] infoDictionary] objectForKey:@"CFBundleVersion"];

4. Duplicate Xcode project

1. Copy/rename the folder into new name

2. Get inside the new folder and rename the .pch and .xcodeproj files

3. Delete the build folder

4. Open .xcodeproj file in text editor, like TextMate or TextWrangler. That’s actually a folder, which contains 4 files (you can also right-click and do Show package contents, which will reveal the files)

5. Open project.pbxproj in text editor and replace all instances of the old name with the new name

6. Load the project file in XCode, do Build/Clean all targets

5. iPhone HTTP request

//prepar request

NSString *urlString = [NSStringstringWithFormat:@"http://urlToSend.com"];

NSMutableURLRequest *request = [[[NSMutableURLRequestalloc] init] autorelease];

[request setURL:[NSURLURLWithString:urlString]];

[request setHTTPMethod:@"POST"];

//set headers

NSString *contentType = [NSStringstringWithFormat:@"text/xml"];

[request addValue:contentType forHTTPHeaderField: @"Content-Type"];

//create the body

NSMutableData *postBody = [NSMutableDatadata];

[postBody appendData:[[NSStringstringWithFormat:@"<xml>"] dataUsingEncoding:NSUTF8StringEncoding]];

[postBody appendData:[[NSStringstringWithFormat:@"<yourcode/>"] dataUsingEncoding:NSUTF8StringEncoding]];

[postBody appendData:[[NSStringstringWithFormat:@"</xml>"] dataUsingEncoding:NSUTF8StringEncoding]];

//post

[request setHTTPBody:postBody];

//get response

NSHTTPURLResponse* urlResponse = nil;

NSError *error = [[NSErroralloc] init];

NSData *responseData = [NSURLConnectionsendSynchronousRequest:request returningResponse:&urlResponse error:&error];

NSString *result = [[NSStringalloc] initWithData:responseData encoding:NSUTF8StringEncoding];

NSLog(@"Response Code: %d", [urlResponse statusCode]);

if ([urlResponse statusCode] >= 200 && [urlResponse statusCode] < 300) {

NSLog(@"Response: %@", result);

//here you get the response

}

6. Load Image from URL and then Resize

NSString* imageURL = [NSString stringWithFormat: @"http://theimageurl.com/?id=%@", [[resultsEntries objectAtIndex:0] objectForKey: @"image_large"]];

NSData* imageData = [[NSDataalloc]initWithContentsOfURL:[NSURLURLWithString:imageURL]];

UIImage* image = [[UIImagealloc] initWithData:imageData];

// resize image

CGSize newSize = CGSizeMake(100, 100);

UIGraphicsBeginImageContext( newSize );// a CGSize that has the size you want

[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

//image is the original UIImage

UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

imageHeight = image.size.height;

[imageMain setImage:newImage];

[imageData release];

[image release ];

7. iPhone: transition between views

// get the view that's currently showing

UIView *currentView = self.view;

// get the the underlying UIWindow, or the view containing the current view view

UIView *theWindow = [currentView superview];

// remove the current view and replace with myView1

[currentView removeFromSuperview];

[theWindow addSubview:view1];

// set up an animation for the transition between the views

CATransition *animation = [CATransition animation];

[animation setDuration:0.5];

[animation setType:kCATransitionPush];

[animation setSubtype:kCATransitionFromRight];

[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];

[[theWindow layer] addAnimation:animation forKey: @"SwitchToView1" ];

8. get iPhone ip address

#include <ifaddrs.h>

#include <arpa/inet.h>

- (NSString*)getIPAddress {

NSString *address = @"error";

structifaddrs *interfaces = NULL;

structifaddrs *temp_addr = NULL;

int success = 0;

// retrieve the current interfaces - returns 0 on success

success = getifaddrs(&interfaces);

if (success == 0) {

// Loop through linked list of interfaces

temp_addr = interfaces;

while(temp_addr != NULL) {

if(temp_addr->ifa_addr->sa_family == AF_INET) {

// Check if interface is en0 which is the wifi connection on the iPhone

// Mac 里用en0

if([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en1"]) {

// Get NSString from C String

address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];

}

temp_addr = temp_addr->ifa_next;

}

// Free memory

freeifaddrs(interfaces);

return address;

}

9. Useful Cocoa Macros

#define APP_NAME [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleName"]

#define APP_VERSION [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"]

#define OPEN_URL(urlString) [[NSWorkspace sharedWorkspace] openURL:[NSURL URLWithString:urlString]]

// Retrieving preference values

#define PREF_KEY_VALUE(x) [[[NSUserDefaultsController sharedUserDefaultsController] values] valueForKey:(x)]

#define PREF_KEY_BOOL(x) [(PREF_KEY_VALUE(x)) boolValue]

#define PREF_SET_KEY_VALUE(x, y) [[[NSUserDefaultsController sharedUserDefaultsController] values] setValue:(y) forKey:(x)]

#define PREF_OBSERVE_VALUE(x, y) [[NSUserDefaultsController sharedUserDefaultsController] addObserver:y forKeyPath:x options:NSKeyValueObservingOptionOld context:nil];

/* key, observer, object */

#define OB_OBSERVE_VALUE(x, y, z) [(z) addObserver:y forKeyPath:x options:NSKeyValueObservingOptionOld context:nil];

#ifdef __OBJC__

staticinlineBOOL isEmpty(id thing) {

return thing == nil

|| ([thing respondsToSelector:@selector(length)]

&& [(NSData *)thing length] == 0)

|| ([thing respondsToSelector:@selector(count)]

&& [(NSArray *)thing count] == 0);

}

#endif

10. iPhone OS - Vibration - Simple Version

Creating a vibration is simple as pie - simpler in fact. It just requires one line of code; two if you add the import line. But as simple as a one-liner is it is better to make it into a function. So here is the one liner, followed by the function.

// NOTE: You need to import the AudioToolbox for access to the vibrate

#import <AudioToolbox/AudioToolbox.h>

// The one-liner:

AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

// The function:

- (void)vibrate {