iPhone 开发过程中的一些小技术的总结

作者： sqw0312

1 随机数的使用

        头文件的引用
        #import <time.h>
        #import <mach/mach_time.h>

        srandom()的使用
        srandom((unsigned)(mach_absolute_time() & 0xFFFFFFFF));

        直接使用 random() 来调用随机数

2 在UIImageView 中旋转图像

        float rotateAngle = M_PI;
   CGAffineTransform transform =CGAffineTransformMakeRotation(rotateAngle);
   imageView.transform = transform;

        以上代码旋转imageView, 角度为rotateAngle, 方向可以自己测试哦！

3 在Quartz中如何设置旋转点

        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"bg.png"]];
        imageView.layer.anchorPoint = CGPointMake(0.5, 1.0);

        这个是把旋转点设置为底部中间。记住是在QuartzCore.framework中才得到支持。

4 创建.plist文件并存储

        NSString *errorDesc;  //用来存放错误信息
   NSMutableDictionary *rootObj = [NSMutableDictionary dictionaryWithCapacity:4]; //NSDictionary, NSData等文件可以直接转化为plist文件
   NSDictionary *innerDict;
   NSString *name;
        Player *player;
   NSInteger saveIndex;

   for(int i = 0; i < [playerArray count]; i++) {
   player = nil;
   player = [playerArray objectAtIndex:i];
   if(player == nil)
   break;
   name = player.playerName;// This "Player1" denotes the player name could also be the computer name
   innerDict = [self getAllNodeInfoToDictionary:player];
   [rootObj setObject:innerDict forKey:name]; // This "Player1" denotes the person who start this game
   }
   player = nil;
   NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:(id)rootObj format:NSPropertyListXMLFormat_v1_0 errorDescription:&errorDesc];

        红色部分可以忽略，只是给rootObj添加一点内容。这个plistData为创建好的plist文件，用其writeToFile方法就可以写成文件。下面是代码：

        /*得到移动设备上的文件存放位置*/
   NSString *documentsPath = [self getDocumentsDirectory];
   NSString *savePath = [documentsPath stringByAppendingPathComponent:@"save.plist"];

   /*存文件*/
   if (plistData) {
                [plistData writeToFile:savePath atomically:YES];
         }
         else {
                NSLog(errorDesc);
                [errorDesc release];
        }

        - (NSString *)getDocumentsDirectory {
                NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
                return [paths objectAtIndex:0];
        }

4 读取plist文件并转化为NSDictionary

        NSString *documentsPath = [self getDocumentsDirectory];
   NSString *fullPath = [documentsPath stringByAppendingPathComponent:@"save.plist"];
   NSMutableDictionary* plistDict = [[NSMutableDictionary alloc] initWithContentsOfFile:fullPath];

5 读取一般性文档文件

        NSString *tmp;
        NSArray *lines; /*将文件转化为一行一行的*/
        lines = [[NSString    stringWithContentsOfFile:@"testFileReadLines.txt"]
                       componentsSeparatedByString:@"/n"];

         NSEnumerator *nse = [lines objectEnumerator];

         // 读取<>里的内容
         while(tmp = [nse nextObject]) {
                  NSString *stringBetweenBrackets = nil;
                  NSScanner *scanner = [NSScanner scannerWithString:tmp];
                  [scanner scanUpToString:@"<" intoString:nil];
                  [scanner scanString:@"<" intoString:nil];
                  [scanner scanUpToString:@">" intoString:&stringBetweenBrackets];

                  NSLog([stringBetweenBrackets description]);
          }

对于读写文件，还有补充，暂时到此。随机数和文件读写在游戏开发中经常用到。所以把部分内容放在这，以便和大家分享，也当记录，便于查找。

6 隐藏NavigationBar
[self.navigationController setNavigationBarHidden:YES animated:YES];

在想隐藏的ViewController中使用就可以了。