IOS开发的一些小技术

让UIImage有缩放功能

@interface UIImage (scale)
-(UIImage*)scaleToSize:(CGSize)size;
@end

 

#import "UIImage+Scale.h"
@implementation UIImage (scale)
-(UIImage*)scaleToSize:(CGSize)size
{
// 创建一个bitmap的context
// 并把它设置成为当前正在使用的context
UIGraphicsBeginImageContext(size);
// 绘制改变大小的图片
[self drawInRect:CGRectMake(0, 0, size.width, size.height)];
// 从当前context中创建一个改变大小后的图片
UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
// 使当前的context出堆栈
UIGraphicsEndImageContext();
// 返回新的改变大小后的图片
return scaledImage;
}
@end

 

截屏的方法：

UIGraphicsBeginImageContext(CGSizeMake(320, 300)); 
   [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
   UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
   UIGraphicsEndImageContext();
   UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);

 

控制log的输出

使用下面的代码， 可以定义一个DebugLog宏，在使用IPHONE模拟器时输出日志。日志的内容包含了时间、当前类、当前函数、当前行及其他参数信息。

我们可以修改TARGET_IPHONE_SIMULATOR替换为其他预定义，或者使用在项目中自定义的宏，以达到不同模式下控制日志的输出。

#if TARGET_IPHONE_SIMULATOR

#define DebugLog(log, ...) NSLog((@"%s [Line %d] " log), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__);
#else
#define DebugLog(log, ...)
#endif

自定义宏的方法:打开项目属性, 找到Preprocessor Macros, 双击, 弹出窗口中点击+按钮即可定义.

 

xcode修改文件注释

修改公司名称：在Terminal中，输入

defaults write com.apple.Xcode PBXCustomTemplateMacroDefinitions '{"ORGANIZATIONNAME" = "company.com";}'

 

随机数的使用

       #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

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！


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。

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];  
       } 

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];

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。

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

在想隐藏的ViewController中使用就可以了。

 

navigationBar 自定义背景

 

@interface UINavigationBar (MyCustomNavBar)

@end

@implementation UINavigationBar (MyCustomNavBar)

- (void) drawRect:(CGRect)rect {

UIImage *barImage = [UIImage imageNamed:@"xxxxx.png"];

[barImage drawInRect:rect];

}

@end