[置顶] iphone随笔

1,获取info.plist文件中的值:

[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"]

2,通知:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(methodName) name:@"NotificationName" object:nil];
[[NSNotificationCenter defaultCenter] postNotificationName:@"NotificationName" object:nil];

3,不让手机处于休眠状态

[[UIApplication sharedApplication] setIdleTimerDisabled:YES];

4,去除空格

 [someStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

5,产生随机数

srandom(time(NULL));
int r = random() % 5;

6,UIButton上字体的对齐方式

[self.myButton setContentHorizontalAlignment:UIControlContentHorizontalAlignmentLeft];

7,UITableViewCell

// Return a cell for the ith row
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
	
	static NSString *identifier = @"cell";
	UITableViewCell	*cell = [tableView dequeueReusableCellWithIdentifier:identifier];
	
	if(!cell){
		
		cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier] autorelease];
		
		// init cell
		cell.textLabel.text = @"test";
	}
	return cell;

}

8，系统版本

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 5.0) { 
       ;
   }

9,how to use printf with NSString

printf("%s", [string UTF8String]);