版本记录
| 版本号 | 时间 |
|---|---|
| V1.0 | 2018.03.20 |
前言
回顾
上一篇我们分析了NSString分类NSString+YYAdd的NSNumber Compatible部分，这一篇我们就看一下Utilities部分。
API 接口
下面我们看一下API接口。
/**
Returns a new UUID NSString
e.g. "D1178E50-2A4D-4F1F-9BD3-F6AAB00E06B1"
*/
+ (NSString *)stringWithUUID;
/**
Returns a string containing the characters in a given UTF32Char.
@param char32 A UTF-32 character.
@return A new string, or nil if the character is invalid.
*/
+ (nullable NSString *)stringWithUTF32Char:(UTF32Char)char32;
/**
Returns a string containing the characters in a given UTF32Char array.
@param char32 An array of UTF-32 character.
@param length The character count in array.
@return A new string, or nil if an error occurs.
*/
+ (nullable NSString *)stringWithUTF32Chars:(const UTF32Char *)char32 length:(NSUInteger)length;
/**
Enumerates the unicode characters (UTF-32) in the specified range of the string.
@param range The range within the string to enumerate substrings.
@param block The block executed for the enumeration. The block takes four arguments:
char32: The unicode character.
range: The range in receiver. If the range.length is 1, the character is in BMP;
otherwise (range.length is 2) the character is in none-BMP Plane and stored
by a surrogate pair in the receiver.
stop: A reference to a Boolean value that the block can use to stop the enumeration
by setting *stop = YES; it should not touch *stop otherwise.
*/
- (void)enumerateUTF32CharInRange:(NSRange)range usingBlock:(void (^)(UTF32Char char32, NSRange range, BOOL *stop))block;
/**
Trim blank characters (space and newline) in head and tail.
@return the trimmed string.
*/
- (NSString *)stringByTrim;
/**
Add scale modifier to the file name (without path extension),
From @"name" to @"name@2x".
e.g.
<table>
<tr><th>Before </th><th>After(scale:2)</th></tr>
<tr><td>"icon" </td><td>"icon@2x" </td></tr>
<tr><td>"icon " </td><td>"icon @2x" </td></tr>
<tr><td>"icon.top" </td><td>"icon.top@2x" </td></tr>
<tr><td>"/p/name" </td><td>"/p/name@2x" </td></tr>
<tr><td>"/path/" </td><td>"/path/" </td></tr>
</table>
@param scale Resource scale.
@return String by add scale modifier, or just return if it's not end with file name.
*/
- (NSString *)stringByAppendingNameScale:(CGFloat)scale;
/**
Add scale modifier to the file path (with path extension),
From @"name.png" to @"name@2x.png".
e.g.
<table>
<tr><th>Before </th><th>After(scale:2)</th></tr>
<tr><td>"icon.png" </td><td>"icon@2x.png" </td></tr>
<tr><td>"icon..png"</td><td>"icon.@2x.png"</td></tr>
<tr><td>"icon" </td><td>"icon@2x" </td></tr>
<tr><td>"icon " </td><td>"icon @2x" </td></tr>
<tr><td>"icon." </td><td>"icon.@2x" </td></tr>
<tr><td>"/p/name" </td><td>"/p/name@2x" </td></tr>
<tr><td>"/path/" </td><td>"/path/" </td></tr>
</table>
@param scale Resource scale.
@return String by add scale modifier, or just return if it's not end with file name.
*/
- (NSString *)stringByAppendingPathScale:(CGFloat)scale;
/**
Return the path scale.
e.g.
<table>
<tr><th>Path </th><th>Scale </th></tr>
<tr><td>"icon.png" </td><td>1 </td></tr>
<tr><td>"icon@2x.png" </td><td>2 </td></tr>
<tr><td>"icon@2.5x.png" </td><td>2.5 </td></tr>
<tr><td>"icon@2x" </td><td>1 </td></tr>
<tr><td>"icon@2x..png" </td><td>1 </td></tr>
<tr><td>"icon@2x.png/" </td><td>1 </td></tr>
</table>
*/
- (CGFloat)pathScale;
/**
nil, @"", @" ", @"\n" will Returns NO; otherwise Returns YES.
*/
- (BOOL)isNotBlank;
/**
Returns YES if the target string is contained within the receiver.
@param string A string to test the the receiver.
@discussion Apple has implemented this method in iOS8.
*/
- (BOOL)containsString:(NSString *)string;
/**
Returns YES if the target CharacterSet is contained within the receiver.
@param set A character set to test the the receiver.
*/
- (BOOL)containsCharacterSet:(NSCharacterSet *)set;
/**
Try to parse this string and returns an `NSNumber`.
@return Returns an `NSNumber` if parse succeed, or nil if an error occurs.
*/
- (nullable NSNumber *)numberValue;
/**
Returns an NSData using UTF-8 encoding.
*/
- (nullable NSData *)dataValue;
/**
Returns NSMakeRange(0, self.length).
*/
- (NSRange)rangeOfAll;
/**
Returns an NSDictionary/NSArray which is decoded from receiver.
Returns nil if an error occurs.
e.g. NSString: @"{"name":"a","count":2}" => NSDictionary: @[@"name":@"a",@"count":@2]
*/
- (nullable id)jsonValueDecoded;
/**
Create a string from the file in main bundle (similar to [UIImage imageNamed:]).
@param name The file name (in main bundle).
@return A new string create from the file in UTF-8 character encoding.
*/
+ (nullable NSString *)stringNamed:(NSString *)name;
1. + (NSString *)stringWithUUID;
该方法返回的是UUID字符串。
示例调用
NSString *resultStr = [NSString stringWithUUID];
NSLog(@"UUID为 = %@", resultStr);
下面看一下输出结果
2018-03-19 14:28:47.932947+0800 JJWebImage[29178:4163246] UUID为 = 03367F43-93A0-41AC-A2AC-650A31F0A40A
方法实现
+ (NSString *)stringWithUUID {
CFUUIDRef uuid = CFUUIDCreate(NULL);
CFStringRef string = CFUUIDCreateString(NULL, uuid);
CFRelease(uuid);
return (__bridge_transfer NSString *)string;
}
2. + (nullable NSString *)stringWithUTF32Char:(UTF32Char)char32;
该方法的作用就是将给定的UTF32Char类型的字符转化为一个NSString类型的字符串，如果这个字符是无效的，那么转化的字符串为nil。
示例调用
下面看一个示例。
UTF32Char number = 97;
NSString *resultStr = [NSString stringWithUTF32Char:number];
NSLog(@"resultStr = %@", resultStr);
下面看一下输出结果
2018-03-19 14:35:36.296366+0800 JJWebImage[29190:4166179] resultStr = a
方法实现
下面看一下该方法的实现
+ (NSString *)stringWithUTF32Char:(UTF32Char)char32 {
char32 = NSSwapHostIntToLittle(char32);
return [[NSString alloc] initWithBytes:&char32 length:4 encoding:NSUTF32LittleEndianStringEncoding];
}
上面方法的实现中调用的两个方法均为系统内部的方法。
3. + (nullable NSString *)stringWithUTF32Chars:(const UTF32Char *)char32 length:(NSUInteger)length;
该方法的作用就是根据给定的 UTF-32字符组和长度，返回一个字符串。
方法实现
下面看一下该方法的实现
+ (NSString *)stringWithUTF32Chars:(const UTF32Char *)char32 length:(NSUInteger)length {
return [[NSString alloc] initWithBytes:(const void *)char32
length:length * 4
encoding:NSUTF32LittleEndianStringEncoding];
}
4. - (void)enumerateUTF32CharInRange:(NSRange)range usingBlock:(void (^)(UTF32Char char32, NSRange range, BOOL *stop))block;
枚举字符串指定范围内的Unicode字符（UTF-32），这里需要说明下几个参数：
-
range：字符串在range范围内遍历子字符串。 -
block：执行遍历的块。-
char32： unicode字符 -
range：这个是接受者，如果range.length == 1，字符是BMP；否则（range.length == 2），该字符在非BMP平面中，并由代理对存储在接收器中。 -
stop： 一个布尔值的引用，块可以通过设置* stop = YES来停止遍历。
-
下面看一下该方法的实现
- (void)enumerateUTF32CharInRange:(NSRange)range usingBlock:(void (^)(UTF32Char char32, NSRange range, BOOL *stop))block {
NSString *str = self;
if (range.location != 0 || range.length != self.length) {
str = [self substringWithRange:range];
}
NSUInteger len = [str lengthOfBytesUsingEncoding:NSUTF32StringEncoding] / 4;
UTF32Char *char32 = (UTF32Char *)[str cStringUsingEncoding:NSUTF32LittleEndianStringEncoding];
if (len == 0 || char32 == NULL) return;
NSUInteger location = 0;
BOOL stop = NO;
NSRange subRange;
UTF32Char oneChar;
for (NSUInteger i = 0; i < len; i++) {
oneChar = char32[i];
subRange = NSMakeRange(location, oneChar > 0xFFFF ? 2 : 1);
block(oneChar, subRange, &stop);
if (stop) return;
location += subRange.length;
}
}
5. - (NSString *)stringByTrim;
该方法的作用就是修剪头部和尾部的空白字符（空格和换行符）。
示例调用
下面看一个示例。
NSString *str = @" aaaa ";
NSLog(@"str = %@, length = %ld", str, str.length);
NSString *resultStr = [str stringByTrim];
NSLog(@"resultStr = %@, length = %ld", resultStr, resultStr.length);
下面看一下输出结果
2018-03-19 15:25:58.879383+0800 JJWebImage[29207:4179554] str = aaaa , length = 6
2018-03-19 15:25:58.879752+0800 JJWebImage[29207:4179554] resultStr = aaaa, length = 4
方法实现
下面看一下该方法的实现
- (NSString *)stringByTrim {
NSCharacterSet *set = [NSCharacterSet whitespaceAndNewlineCharacterSet];
return [self stringByTrimmingCharactersInSet:set];
}
6. - (NSString *)stringByAppendingNameScale:(CGFloat)scale;
下面我们看一下这个方法
/**
Add scale modifier to the file name (without path extension),
From @"name" to @"name@2x".
e.g.
<table>
<tr><th>Before </th><th>After(scale:2)</th></tr>
<tr><td>"icon" </td><td>"icon@2x" </td></tr>
<tr><td>"icon " </td><td>"icon @2x" </td></tr>
<tr><td>"icon.top" </td><td>"icon.top@2x" </td></tr>
<tr><td>"/p/name" </td><td>"/p/name@2x" </td></tr>
<tr><td>"/path/" </td><td>"/path/" </td></tr>
</table>
@param scale Resource scale.
@return String by add scale modifier, or just return if it's not end with file name.
*/
- (NSString *)stringByAppendingNameScale:(CGFloat)scale;
其实，就是实现类似@"name" 到 @"name@2x"这样的功能。
方法实现
下面看一下该方法的实现
- (NSString *)stringByAppendingNameScale:(CGFloat)scale {
if (fabs(scale - 1) <= __FLT_EPSILON__ || self.length == 0 || [self hasSuffix:@"/"]) return self.copy;
return [self stringByAppendingFormat:@"@%@x", @(scale)];
}
7. - (NSString *)stringByAppendingPathScale:(CGFloat)scale;
看一下这个方法
/**
Add scale modifier to the file path (with path extension),
From @"name.png" to @"name@2x.png".
e.g.
<table>
<tr><th>Before </th><th>After(scale:2)</th></tr>
<tr><td>"icon.png" </td><td>"icon@2x.png" </td></tr>
<tr><td>"icon..png"</td><td>"icon.@2x.png"</td></tr>
<tr><td>"icon" </td><td>"icon@2x" </td></tr>
<tr><td>"icon " </td><td>"icon @2x" </td></tr>
<tr><td>"icon." </td><td>"icon.@2x" </td></tr>
<tr><td>"/p/name" </td><td>"/p/name@2x" </td></tr>
<tr><td>"/path/" </td><td>"/path/" </td></tr>
</table>
@param scale Resource scale.
@return String by add scale modifier, or just return if it's not end with file name.
*/
- (NSString *)stringByAppendingPathScale:(CGFloat)scale;
其实就是实现从@"name.png" 到 @"name@2x.png"这样的类似转化。
方法实现
下面看一下该方法的实现
- (NSString *)stringByAppendingPathScale:(CGFloat)scale {
if (fabs(scale - 1) <= __FLT_EPSILON__ || self.length == 0 || [self hasSuffix:@"/"]) return self.copy;
NSString *ext = self.pathExtension;
NSRange extRange = NSMakeRange(self.length - ext.length, 0);
if (ext.length > 0) extRange.location -= 1;
NSString *scaleStr = [NSString stringWithFormat:@"@%@x", @(scale)];
return [self stringByReplacingCharactersInRange:extRange withString:scaleStr];
}
8. - (CGFloat)pathScale;
下面我们看一下该方法
/**
Return the path scale.
e.g.
<table>
<tr><th>Path </th><th>Scale </th></tr>
<tr><td>"icon.png" </td><td>1 </td></tr>
<tr><td>"icon@2x.png" </td><td>2 </td></tr>
<tr><td>"icon@2.5x.png" </td><td>2.5 </td></tr>
<tr><td>"icon@2x" </td><td>1 </td></tr>
<tr><td>"icon@2x..png" </td><td>1 </td></tr>
<tr><td>"icon@2x.png/" </td><td>1 </td></tr>
</table>
*/
- (CGFloat)pathScale;
方法实现
下面看一下该方法的实现
- (CGFloat)pathScale {
if (self.length == 0 || [self hasSuffix:@"/"]) return 1;
NSString *name = self.stringByDeletingPathExtension;
__block CGFloat scale = 1;
[name enumerateRegexMatches:@"@[0-9]+\\.?[0-9]*x$" options:NSRegularExpressionAnchorsMatchLines usingBlock: ^(NSString *match, NSRange matchRange, BOOL *stop) {
scale = [match substringWithRange:NSMakeRange(1, match.length - 2)].doubleValue;
}];
return scale;
}
9. - (BOOL)isNotBlank;
该方法的作用就是用来判断是否是空白。nil, @"", @" ", @"\n"会返回NO，其他返回YES。
示例调用
下面看一个示例。
NSString *str = @" ";
BOOL isNotBlank = [str isNotBlank];
NSLog(@"isNotBlank = %d", isNotBlank);
NSString *str1 = @"aaaa";
BOOL isNotBlank1 = [str1 isNotBlank];
NSLog(@"isNotBlank1 = %d", isNotBlank1);
下面看一下输出结果
2018-03-19 15:44:04.690104+0800 JJWebImage[29214:4184283] isNotBlank = 0
2018-03-19 15:44:04.690198+0800 JJWebImage[29214:4184283] isNotBlank1 = 1
方法实现
下面看一下该方法的实现
- (BOOL)isNotBlank {
NSCharacterSet *blank = [NSCharacterSet whitespaceAndNewlineCharacterSet];
for (NSInteger i = 0; i < self.length; ++i) {
unichar c = [self characterAtIndex:i];
if (![blank characterIsMember:c]) {
return YES;
}
}
return NO;
}
10. - (BOOL)containsString:(NSString *)string;
这个方法很好理解，就是判断一个字符串是否包含另外一个字符串。
示例调用
下面看一个示例。
NSString *str = @"abcde";
BOOL isContain = [str containsString:@"a"];
NSLog(@"isContain = %d", isContain);
NSString *str1 = @"abcde";
BOOL isContain1 = [str1 containsString:@"f"];
NSLog(@"isContain = %d", isContain1);
下面我们看一下输出结果
2018-03-19 16:16:17.588977+0800 JJWebImage[29217:4192114] isContain = 1
2018-03-19 16:16:17.589063+0800 JJWebImage[29217:4192114] isContain = 0
方法实现
下面看一下该方法的实现
- (BOOL)containsString:(NSString *)string {
if (string == nil) return NO;
return [self rangeOfString:string].location != NSNotFound;
}
11. - (BOOL)containsCharacterSet:(NSCharacterSet *)set;
这个方法的作用就是字符串是否包含某个字符。
示例调用
下面看一个示例。
NSString *str = @"abc de";
BOOL isContain = [str containsCharacterSet:[NSCharacterSet whitespaceCharacterSet]];
NSLog(@"isContain = %d", isContain);
NSString *str1 = @"abcde";
BOOL isContain1 = [str1 containsCharacterSet:[NSCharacterSet whitespaceCharacterSet]];
NSLog(@"isContain1 = %d", isContain1);
下面看一下输出结果
2018-03-19 16:22:55.638426+0800 JJWebImage[29222:4194182] isContain = 1
2018-03-19 16:22:55.638514+0800 JJWebImage[29222:4194182] isContain1 = 0
方法实现
下面看一下该方法的实现
- (BOOL)containsCharacterSet:(NSCharacterSet *)set {
if (set == nil) return NO;
return [self rangeOfCharacterFromSet:set].location != NSNotFound;
}
12. - (nullable NSNumber *)numberValue;
这个方法很简单就不举例了，就是将字符串转化为NSNumber数据类型，如果不能转换，就返回nil。
下面看一下方法实现
- (NSNumber *)numberValue {
return [NSNumber numberWithString:self];
}
13. - (nullable NSData *)dataValue;
这个方法很简单就不举例了，就是将字符串转化为NSData数据类型，使用的是UTF - 8编码。
下面看一下方法实现
- (NSData *)dataValue {
return [self dataUsingEncoding:NSUTF8StringEncoding];
}
14. - (NSRange)rangeOfAll;
这个方法很简单就不举例了，就是将返回字符串的range - NSMakeRange(0, self.length)。
下面我们看一下方法的实现过程。
- (NSRange)rangeOfAll {
return NSMakeRange(0, self.length);
}
15. - (nullable id)jsonValueDecoded;
该方法的作用就是将指定的Json字符串转化为字典或者数组。
方法实现
下面看一下该方法的实现。
- (id)jsonValueDecoded {
return [[self dataValue] jsonValueDecoded];
}
下面就是调用NSData分类的这个方法了。
- (id)jsonValueDecoded {
NSError *error = nil;
id value = [NSJSONSerialization JSONObjectWithData:self options:kNilOptions error:&error];
if (error) {
NSLog(@"jsonValueDecoded error:%@", error);
}
return value;
}
16. + (nullable NSString *)stringNamed:(NSString *)name;
该方法的作用就是从main bundle文件中创建字符串，类似于[UIImage imageNamed:]。返回值为文件中UTF - 8编码的字符串。
方法实现
下面看一下该方法的实现。
+ (NSString *)stringNamed:(NSString *)name {
NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:@""];
NSString *str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:NULL];
if (!str) {
path = [[NSBundle mainBundle] pathForResource:name ofType:@"txt"];
str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:NULL];
}
return str;
}
后记
本篇我们分析了Utilities部分的功能，主要就是涉及到字符串处理的一些小的工具，比如获取UUID字符串等，喜欢的给个赞~~~