iOS

[MEMO/TIPS] iPhone class / method / instance naming convention

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class  : 大寫開頭

method / instance : 小寫

Property List / SQLite 寫法 sample

類似 printf 的寫法

NSString *debugMsg = [NSString stringWithFormat:@"Process %d", 1];

取亂數

定義:
#define RANDOM_SEED() srandom(time(NULL))
#define RANDOM_INT(__MIN__, __MAX__) ((__MIN__) + random() % ((__MAX__+1) - (__MIN__)))

// --- 這樣用
    NSLog(@"%d" , RANDOM_INT(0,9) );

取 unixtime :

    NSDate *past = [NSDate date];
    NSTimeInterval oldTime = [past timeIntervalSinceDate:[NSDate dateWithNaturalLanguageString:@"01/01/1970"]];
    NSString *unixTime = [[NSString alloc] initWithFormat:@"%0.0f", oldTime];
    NSLog(@"%@" , unixTime);

印出 debug message / popup alert 的寫法:

// ---
-(void) printdebug:(id)msg {
	NSLog(@"%@", msg);
}

// ---
-(void) displayAlertMessage:(id)msg {
	// Display AlertView
	UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"___Alert___" message:msg
                        delegate:self cancelButtonTitle:@"Close" otherButtonTitles: nil];
	[alert show];
	[alert release];
}

Objective-C 奇怪的 null detect!

	if ( (NSNull *)[item objectForKey:@"nick"]==[NSNull null] ) {
		// FOR GUEST DATA
		cell.textLabel.text = @"Guest";
	} else {
		// FOR MEMBER DATA
		cell.textLabel.text = [item objectForKey:@"nick"];
	}

ASYNC network 寫法:

http://mobile.tutsplus.com/tutorials/iphone/iphone-json-twitter-api/

—-

我的第一隻 iPhone 程式 – HelloMap !

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hellomap2

這隻程式會展現一個地圖, 並以目前定位的座標為中心點, 及一個按鈕,按下按鈕會把座標及UDID傳送到 server , 由 server 端的程式記錄下來, 並且 server 端亂數送出一個水果名回傳給 iPhone client 端, iPhone client 端再把這水果名 show 在 iPhone screen上.

底下是片斷程式碼:

FirstViewController.h :

#import 
#import 
#import 

@interface FirstViewController : UIViewController  {
  IBOutlet MKMapView *mapView;
  CLLocationManager *locationManager;
  CLLocation *currentLocation;

}

- (IBAction) updateLocation;

@end

 

FirstViewController.m :

- (void)viewDidLoad {
  [super viewDidLoad];

  if (locationManager==nil) {
    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
  }

  [locationManager startUpdatingLocation];

  [mapView setMapType:MKMapTypeStandard];
}

- (void)locationManager:(CLLocationManager *)manager
  didUpdateToLocation:(CLLocation *)newLocation
       fromLocation:(CLLocation *)oldLocation {

  NSLog(@"Location : %.6f , %.6f", newLocation.coordinate.latitude , newLocation.coordinate.longitude );

  MKCoordinateRegion region = [mapView region];

  region.center = newLocation.coordinate;

  MKCoordinateSpan span;
  span.latitudeDelta = 0.01;
  span.longitudeDelta = 0.01;
  region.span = span;
  [mapView setRegion:region animated:TRUE];

  //
  if ( currentLocation != nil) {
    [currentLocation release];
    currentLocation = nil;
  }
  currentLocation = [newLocation copy];

}
- (IBAction) updateLocation {

  if(currentLocation==nil)
    return;

  UIDevice *device=[[UIDevice alloc] init];

  NSString *URLString=[[NSString alloc] initWithFormat:@"http://z.monster.tw/save_location.php?lat=%.6f&lng=%.6f&id=%@"
             ,currentLocation.coordinate.latitude
             ,currentLocation.coordinate.longitude
             ,device.uniqueIdentifier];

  [device release];

  NSLog(@"%@",URLString);

  // Send Request
  NSURLRequest *request=[NSURLRequest requestWithURL:[NSURL URLWithString:[URLString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]
                       cachePolicy:NSURLRequestReloadIgnoringCacheData
                     timeoutInterval:20.0]; 

  NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
  NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];

  NSLog(@"%@",returnString);  

  // Display AlertView
  UIAlertView *alert = [[UIAlertView alloc] initWithTitle:returnString message:@"Thanks!"
                           delegate:self cancelButtonTitle:@"Close" otherButtonTitles: nil];
  [alert show];
  [alert release];  

  [returnString release];
}

A simple Objective-C Method Declaration and Definition

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定義

- (void) sayHello: (NSString*) name;

implementation :

- (void) sayHello: (NSString*) name {
  NSMutableString *message = [[NSMutableString alloc] initWithString:@"Hello there "];
  [message appendString:name];
  NSLog(message);
  [message release];
}
//

simple.m 宣告 sayHello method:

#import "Simple.h"
@implementation Simple
- (void) sayHello: (NSString *) name {
  NSMutableString *message = [[NSMutableString alloc] initWithString:@"Hello there "];
  [message appendString:name];
  NSLog(message);
  [message release];
}
@end
//

simple.h

#import 
@interface Simple : NSObject {
}
-(void) sayHello: (NSString *) name;
@end
//

main 呼叫 sayHello method:

#import 
#import "Simple.h"
int main(int argc, char *argv[]) {
  NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
  Simple * mySimple = [[Simple alloc] init];
  [mySimple sayHello:@"James"];
  [mySimple release];
  int retVal = UIApplicationMain(argc, argv, nil, nil);
  [pool release];
  return retVal;
}
//

objective-c-intreface