Object-C 中各数据类型转换 NSData转NSString，Byte，UIImage

最新推荐文章于 2019-08-12 13:38:22 发布

转载最新推荐文章于 2019-08-12 13:38:22 发布 · 1.8k 阅读

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本文详细介绍iOS开发中不同数据类型间的转换方法，包括NSString与NSData、NSData与Byte、NSData与UIImage之间的相互转换，以及NSData合并和NSString合并的具体实现。

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转：http://www.cnblogs.com/cpcpc/archive/2012/06/15/2550230.html
1，NSData 与 NSString
　　NSData --> NSString
　　NSString *aString = [[NSString alloc] initWithData:adata encoding:NSUTF8StringEncoding];
　　NSString --> NSData
　　NSString *aString = @"1234";
　　NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];
	
   //将string转换为指定编码 
   NSString *buf = [[[NSString alloc] initWithData:data encoding:encodin] autorelease];
    	
2，NSData 与 Byte
　　NSData --> Byte
　　NSString *testString = @"1234567890";
　　NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
　　Byte *testByte = (Byte *)[testData bytes];
　　Byte --> NSData
　　Byte byte[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};
　　NSData *adata = [[NSData alloc] initWithBytes:byte length:24];

3，NSData 与 UIImage
　　NSData --> UIImage
　　UIImage *aimage = [UIImage imageWithData: imageData];
　　//从本地文件沙盒中取图片并转换为NSData
　　NSString *path = [[NSBundle mainBundle] bundlePath];
　　NSString *name = [NSString stringWithFormat:@"ceshi.png"];
　　NSString *finalPath = [path stringByAppendingPathComponent:name];
　　NSData *imageData = [NSData dataWithContentsOfFile: finalPath];
　　UIImage *aimage = [UIImage imageWithData: imageData];
　　UIImage－> NSData
　　NSData *imageData = UIImagePNGRepresentation(aimae);

4，NSData 与 NSMutableData
　　NSData --> MSMutableData
　　NSData *data=[[NSData alloc]init];
　　NSMutableData *mdata=[[NSMutableData alloc]init];   
　　mdata=[NSData dataWithData:data];

5，NSData合并为一个NSMutableData
- (NSString *)filePathWithName:(NSString *)filename{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    return [documentsDirectory stringByAppendingPathComponent:filename];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    //音频文件路径
    NSString *mp3Path1 = [[NSBundle mainBundle] pathForResource:@"1" ofType:@"mp3"];
    NSString *mp3Path2 = [[NSBundle mainBundle] pathForResource:@"2" ofType:@"mp3"];
    
    //音频数据
    NSData *sound1Data = [[NSData alloc] initWithContentsOfFile: mp3Path1];
    NSData *sound2Data = [[NSData alloc] initWithContentsOfFile: mp3Path2];
    
    //合并音频
    NSMutableData *sounds = [NSMutableData alloc];
    [sounds appendData:sound1Data];
    [sounds appendData:sound2Data];
    NSLog(@"data length:%d", [sounds length]);
    	
    //保存音频
    [sounds writeToFile:[self filePathWithName:@"tmp.mp3"] atomically:YES];
    
    [window makeKeyAndVisible];
    return YES;
}

6，NSString 合并
    NSString* string; // 结果字符串
    NSString* string1, string2; //已存在的字符串，需要将string1和string2连接起来
    //方法1. 
    string = [NSString initWithFormat:@"%@,%@", string1, string2 ];
    //方法2. 
    string = [string1 stringByAppendingString:string2];
    //方法3 . 
    string = [string stringByAppendingFormat:@"%@,%@",string1, string2];