使用框架时如何将 NSMutableString 转换为 NSString？
我编写了一个 Objective-C 框架，它使用 NSMutableString 构建一些 HTML 代码，该代码将值作为 NSString 返回。
我已经在接口 .h 文件中声明了 NSString 和 NSMutableString：
NSString *_outputLanguage; // Tests language output
NSMutableString *outputBuilder;
NSString *output;
这是框架实现 .m 代码中的示例（我无法打印实际代码，因为它是专有的）：
-(NSString*)doThis:(NSString*)aString num:(int)aNumber {
if ([outputBuilder length] != 0) {
[outputBuilder setString:@""];
}
if ([_outputLanguage isEqualToString:@"html"]) {
[outputBuilder appendString:@"Some Text..."];
[outputBuilder appendString:aString];
[outputBuilder appendString:[NSString stringWithFormat:@"%d", aNumber]];
}
else if ([_outputLanguage isEqualToString:@"xml"]) {
[outputBuilder appendString:@"Etc..."];
}
else {
[outputBuilder appendString:@""];
}
output = outputBuilder;
return output;
}
当我编写文本程序时，NSLog 只是打印出“ （无效的）”。我在那里写的代码是：
TheClass *instance = [[TheClass alloc] init];
NSString *testString = [instance doThis:@"This String" num:20];
NSLog(@"%@", testString);
[instance release];
我希望这是足够的信息！
I have written an Objective-C framework which builds some HTML code with NSMutableString which returns the value as an NSString.
I have declared an NSString and NSMutableString in the inteface .h file:
NSString *_outputLanguage; // Tests language output
NSMutableString *outputBuilder;
NSString *output;
This is a sample from the framework implementation .m code (I cannot print the actual code as it is proprietary):
-(NSString*)doThis:(NSString*)aString num:(int)aNumber {
if ([outputBuilder length] != 0) {
[outputBuilder setString:@""];
}
if ([_outputLanguage isEqualToString:@"html"]) {
[outputBuilder appendString:@"Some Text..."];
[outputBuilder appendString:aString];
[outputBuilder appendString:[NSString stringWithFormat:@"%d", aNumber]];
}
else if ([_outputLanguage isEqualToString:@"xml"]) {
[outputBuilder appendString:@"Etc..."];
}
else {
[outputBuilder appendString:@""];
}
output = outputBuilder;
return output;
}
When I wrote a text program, NSLog simply printed out "(null)". The code I wrote there was:
TheClass *instance = [[TheClass alloc] init];
NSString *testString = [instance doThis:@"This String" num:20];
NSLog(@"%@", testString);
[instance release];
I hope this is enough information!
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我猜你忘记
分配/初始化你的字符串......I'm guessing that you're forgetting to
alloc/inityour strings...确保
outputBuilder有效。你在哪里alloc/init'ing它？Make sure
outputBuilderis valid. Where are youalloc/init'ing it?您的
doThis:方法似乎没有初始化outputBuilder。因此，如果它是空指针，则不会对其执行任何操作。Your
doThis:method doesn't seem to initialiseoutputBuilder. So if it is a null pointer, then nothing will be done to it.