[c]dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
\n \/\/ \u8017\u65f6\u7684\u64cd\u4f5c
\n dispatch_async(dispatch_get_main_queue(), ^{
\n \/\/ \u66f4\u65b0\u754c\u9762
\n });
\n}); [\/c]<\/p>\n
<\/p>\n
example:<\/p>\n
[c]dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
\n NSURL * url = [NSURL URLWithString:@"http:\/\/learn-house.idv.tw\/xxx.jpg"];
\n NSData * data = [[NSData alloc]initWithContentsOfURL:url];
\n UIImage *image = [[UIImage alloc]initWithData:data];
\n if (data != nil) {
\n dispatch_async(dispatch_get_main_queue(), ^{
\n self.imageView.image = image;
\n });
\n }
\n});[\/c]<\/p>\n
serial \u7684 queue<\/pre>\n[c]dispatch_async(dispatch_queue_create("com.learnhouse.queue", DISPATCH_QUEUE_SERIAL), ^{
\n \/\/your code
\n});[\/c]<\/p>\nNSDictionary<\/h1>\n
[c]\/\/\u4e00\u500bkey – value
\nNSDictionary *dic1 = [NSDictionary dictionaryWithObject:@"@123" forKey:@"key1"];
\n\/\/\u5169\u500b\u4ee5\u4e0a key – value
\nNSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:@"value1",@"key1",@"value2",@"key2" ,nil];
\n\/\/\u7528\u5b57\u5178\u70ba\u53e6\u4e00\u500b\u5b50\u5b57\u5178\u521d\u59cb\u5316
\nNSDictionary *dic3 = [NSDictionary dictionaryWithDictionary:dic1]
\n\/\/\u65b0\u65b9\u6cd5\u8ce6\u503c
\nNSDictionary *dic4 = @{@"key1": @"value1",@"key2": @"value2"};
\n\/\/\u4ee5\u70ba\u4ef6\u5167\u5bb9\u521d\u59cb\u5316\u4e00\u500b\u5b57\u5178
\nNSDictionary *dic5 = [NSDictionary dictionaryWithContentsOfFile:path];
\n\/\/\u5c07\u5b57\u5178\u7684key\u8f49\u6210\u4e00\u500b\u679a\u8209\u5c0d\u8c61\uff0c\u7528\u65bc\u904d\u6b77
\nNSEnumerator *enumerator = [dic4 keyEnumerator];
\n\/\/\u5c07\u5b57\u5178\u7684value\u8f49\u6210\u4e00\u500b\u679a\u8209\u5c0d\u8c61\uff0c\u7528\u65bc\u904d\u6b77
\nNSEnumerator *enumerator = [dic6 objectEnumerator];[\/c]<\/p>\n\u5b57\u5178\u7684\u5e38\u7528\u65b9\u6cd5<\/p>\n
[c]\/\/\u8fd4\u56de\u5b57\u5178\u9375\u503c\u5c0d\u7684\u500b\u6578
\nNSInteger count = [dic4 count];
\n\/\/\u901a\u904ekey\u7372\u53d6\u5c0d\u61c9\u7684value\u5c0d\u8c61
\nNSObject *object = [dic2 objectForKey:@"key1"];
\n\/\/\u7372\u53d6\u6240\u6709\u9375\u7684\u96c6\u5408
\nNSArray *keys = [dic3 allKeys];
\n\/\/\u7372\u53d6\u6240\u6709\u503c\u7684\u96c6\u5408
\nNSArray *values = [dic3 allValues];[\/c]<\/p>\nNSMutableDictionary<\/h1>\n
\u53ef\u8b8a\u5b57\u5178\u8207\u4e0d\u53ef\u8b8a\u5b57\u5178\u7684\u521d\u59cb\u5316\u65b9\u6cd5\u76f8\u540c\uff0c\u4f46\u4e0d\u80fd\u7528\u65b0\u65b9\u6cd5\u3002\u4e0b\u9762\u53ea\u4ecb\u7d39\u5e38\u7528\u65b9\u6cd5<\/p>\n
\u5e38\u7528\u65b9\u6cd5<\/p>\n
[c]NSMutableDictionary *dic6 = [NSMutableDictionary dictionary];
\n\/\/\u50cf\u5b57\u5178\u4e2d\u8ffd\u52a0\u4e00\u500b\u65b0\u7684 key5 \u548c value5
\n[dic6 setObject:@"value5" forKey:@"key5"];
\n\/\/\u50cf\u5b57\u5178\u4e2d\u6dfb\u52a0\u6574\u500b\u5b57\u5178\u5c0d\u8c61
\n[dic6 addEntriesFromDictionary:dic1];
\n\/\/\u5c07\u5b57\u51786\u7684\u5c0d\u8c61\u5167\u5bb9\u8a2d\u7f6e\u8207\u5b57\u51781\u7684\u5c0d\u8c61\u5167\u5bb9\u76f8\u540c
\n[dic6 setDictionary:dic1];
\n\/\/\u522a\u9664\u9375\u6240\u5c0d\u61c9\u7684\u9375\u503c\u5c0d
\n[dic6 removeObjectForKey:@"key1"];
\n\/\/\u522a\u9664\u6578\u7d44\u4e2d\u7684\u6240\u6709key \u5c0d\u61c9\u7684\u9375\u503c\u5c0d
\nNSArray *array = @[@"key1",@"key2",@"key3"];
\n[dic6 removeObjectsForKeys:array];
\n\/\/\u79fb\u9664\u5b57\u5178\u4e2d\u7684\u6240\u6709\u5c0d\u8c61
\n[dic6 removeAllObjects];[\/c]<\/p>\n\u4e00\u822c\u904d\u6b77<\/p>\n
[c]for (int i = 0; i < [dic3 count]; i++) {
\n id key = [keys objectAtIndex:i];
\n id obj = [dic3 objectForKey:key];
\n NSLog(@"%@",obj);
\n}[\/c]<\/p>\n\u5feb\u901f\u904d\u6b77<\/p>\n
[c]for (id key in dic3) {
\n id obj = [dic3 objectForKey:key];
\n NSLog(@"%@",obj);
\n}[\/c]<\/p>\n\u679a\u8209\u7684\u8fa6\u6cd5\u904d\u6b77<\/p>\n
[c]NSEnumerator *enumerator = [dic4 keyEnumerator];
\nid key = [enumerator nextObject];
\nwhile (key) {
\n id obj = [dic4 objectForKey:key];
\n NSLog(@"%@",obj);
\n key = [enumerator nextObject];
\n}[\/c]<\/p>\n\u5beb\u5165BOOL\u503c<\/p>\n
[c][dicTemp setObject:[NSNumber numberWithBool:YES] forKey:@"is_default"];
\n\/\/or
\ndicTemp[@"is_default"] = @YES;[\/c]<\/p>\nNSString<\/h1>\n
\u5207\u5b57\u4e32\u7684\u65b9\u6cd5
\n(NSString *)substringFromIndex:(NSUInteger)anIndex
\n(NSString *)substringToIndex:(NSUInteger)anIndex
\n(NSString *)substringWithRange:(NSRange)aRange<\/p>\nexample:<\/p>\n
[c]NSString *str = @"1234567890";
\nNSLog(@"Original String: %@", str);
\nNSLog(@"substringFromIndex: 5 ==> %@", [str substringFromIndex:5]);
\nNSLog(@"substringToIndex: 5 ==> %@", [str substringToIndex:5]);
\nNSLog(@"substringWithRange: from 7, length 3 ==> %@", [str substringWithRange:NSMakeRange(7, 3)]);[\/c]<\/p>\nresult:<\/p>\n
[c]Original String: 1234567890
\nsubstringFromIndex: 5 ==> 67890
\nsubstringToIndex: 5 ==> 12345
\nsubstringWithRange: from 7, length 3 ==> 890[\/c]<\/p>\n\u5b57\u4e32\u53d6\u4ee3
\n– (NSString *)stringByReplacingOccurrencesOfString:(NSString *)target
\nwithString:(NSString *)replacement<\/p>\nexample:<\/p>\n
[c]NSString *str = @"This is a string";
\nstr = [str stringByReplacingOccurrencesOfString:@"string"
\n withString:@"duck"];
\n\/\/This is a duck
\n[\/c]<\/p>\n\u524d\u6233\u5b57\u4e32\u6bd4\u5c0d<\/p>\n
[c]if ([myString hasPrefix:@"http"]) {
\n}[\/c]<\/p>\nNSString \u548c NSDate \u4e92\u76f8\u8f49\u63db<\/h1>\n
\u7531 NSDate \u8f49\u63db\u70ba NSString:<\/p>\n
[c]NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
\n[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
\nNSString *strDate = [dateFormatter stringFromDate:[NSDate date]];
\nNSLog(@"%@", strDate);[\/c]<\/p>\n\u7531 NSString \u8f49\u63db\u70ba NSDate:<\/p>\n
[c]NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
\n[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
\nNSDate *date = [dateFormatter dateFromString:@"2010-08-04 16:01:03"];
\nNSLog(@"%@", date);[\/c]<\/p>\nchar \u8f49\u63db\u6210 NSString<\/h1>\n
char myChar = ‘r’;
\n[NSString stringWithFormat:@”%c” , myChar];<\/p>\nNSString \u8f49\u63db\u6210 char<\/h1>\n
const char *myChar = [myString UTF8String];<\/p>\n
\u6570\u7ec4\u4e2d\u7684\u6700\u5927\u503c\u8ddf\u6700\u5c0f\u503c<\/h1>\n
[c]NSArray * arr = [NSArray arrayWithObjects:@"1",@"10",@"5", @"31", nil];
\n\/\/\u5f97\u5230\u6570\u7ec4\u4e2d\u6700\u5c0f\u7684\u503c
\nNSInteger min = [[arr valueForKeyPath:@"@min.intValue"] integerValue];
\n\/\/\u5f97\u5230\u6570\u7ec4\u4e2d\u6700\u5927\u7684\u503c
\nNSInteger max = [[arr valueForKeyPath:@"@max.intValue"] integerValue];
\nNSLog(@"min = %ld max = %ld", (long)min, (long)max);[\/c]<\/p>\nSplit an NSString<\/h1>\n
[c]NSArray* foo = [@"10\/04\/2011" componentsSeparatedByString: @"\/"];
\nNSString* firstBit = [foo objectAtIndex: 0];[\/c]<\/p>\nUITextField<\/h1>\n