[英]Objective-C framework used in Swift - ambiguous use of method error
[英]Error Handling an Objective-C framework in Swift Language
我正在使用Objective-C框架创建一个iOS Swift应用程序。
框架头文件(SMPort.h):
// ... do all the import //
@interface PortException : NSException
{
}
@end
@interface PortInfo : NSObject
- (id)initWithPortName:(NSString *)portName_ macAddress:(NSString *)macAddress_ modelName:(NSString *)modelName_;
@property(retain, readonly) NSString *portName;
@property(retain, readonly) NSString *macAddress;
@property(retain, readonly) NSString *modelName;
@property(readonly, getter=isConnected) BOOL connected;
@end
@interface SMPort : NSObject {
void * m_port;
WBluetoothPort* wBluetoothPort;
BluetoothPort* bluetoothPort;
NSString * m_portName;
NSString * m_portSettings;
int m_ioTimeoutMillis;
BOOL checkedBlockSupport;
}
@property(assign, readwrite, nonatomic) u_int32_t endCheckedBlockTimeoutMillis;
// Initializer and staff methods...
/*!
* This function retreives the device's detailed status.
*
* @param starPrinterStatus Pointer to a StarPrinterStatus_n structure where the devices detailed status is written
* (either StarPrinterStatus_0, StarPrinterStatus_1, or StarPrinterStatus_2).
* @param level Integer designating the level of status structure (either 0, 1, or 2).
*
* @note Throws PortException on failure.
*/
- (void)getParsedStatus:(void *)starPrinterStatus :(u_int32_t)level;
// The other methods...
我阅读了框架文档,我发现了这个Objective-C代码(完美地运行):
@try
{
[starPort getParsedStatus:&status :2];
}
@catch (PortException *exception){
// Print error
}
所以我尝试在Swift 2.1中做这样的事情:
do{
try starPort.getParsedStatus(status , 2)
}
catch is PortException{
print("error")
}
但是当错误发生时 ,编译器会停止应用程序,说我没有捕到该错误:
2015-11-18 18:59:51.297 $$$$$ [$$$$$:$$$$$] *由于未捕获的异常'PortException'终止应用程序,原因:'Native GetParsedStatusEx failed'* First throw call堆栈:(0x2524a67b 0x36e76e17 0xa3af7 0x6f378 0x6f3d8 0x6fbc0 0x6fd10 0x6ef00 0x87bf8 0x87d80 0x29371559 0x293714e9 0x293594ff 0x29370e45 0x29370abf 0x2936947f 0x2933a561 0x29338bdb 0x2520dbff 0x2520d7ed 0x2520bb5b 0x2515f119 0x2515ef05 0x2e2fcac9 0x293a1f15 0x7f410 0x375e5873)的libc ++ abi.dylib:与类型PortException的未捕获的异常终止
我也尝试过这样的事情:
func doGPS() throws { starPort.getParsedStatus(status ,2) }
func test() {
do {
try doGPS()
} catch is PortException{
print("Error")
} catch{
print("WTF? : \(error)")
}
}
test()
得到相同的结果......
那么,我怎样才能在Swift 2.1中捕获这个错误?
这里是SMPort.h的完整代码https://github.com/gabebear/receiptbooth/blob/master/StarIO.framework/Headers/SMPort.h
这个问题问得好! 这是一个需要解决的合法问题。 不幸的是,你现在无法做到这一点。 原因如下:
Swift异常处理与Exceptions无关。 实际上,你无法捕获NSException,这是在Obj-C方面提出的。 Swift捕获NSError,实际上(在Swift中)是一个Enum。 简而言之,在Objective-C中有两种处理错误的模式:1。引发NSException 2.返回NSError
正如我解释的那样,您无法处理使用第一种方法引发的错误。 因此,您确实必须使用NSError修改Objective-C代码以符合第二种方法。
一些好的链接:
https://www.bignerdranch.com/blog/error-handling-in-swift-2/ https://forums.developer.apple.com/thread/7582
所以,多亏了@Peyman和@dan,我写了两个新的Objective-C文件,我实现了一个新方法(扩展SMPort
类),捕获错误并返回一个NSError
SMPort + handler.h中
#import <Foundation/Foundation.h>
#import <StarIO/SMPort.h>
@interface SMPort ( Handler )
- (BOOL)getParsedStatusThrowing:(void *)starPrinterStatus
level:(u_int32_t)level
didFailWithError:(NSError **)error;
@end
SMPort + Handler.m
#import "SMPort+Handler.h"
@implementation SMPort ( Handler )
- (BOOL)getParsedStatusThrowing:(void *)starPrinterStatus
level:(u_int32_t)level
didFailWithError:(NSError **)error
{
@try
{
[self getParsedStatus:&starPrinterStatus :level];
return TRUE;
}
@catch (PortException *exception){
NSMutableDictionary* details = [NSMutableDictionary dictionary];
// exemption.name in my case should be PortExeption
[details setValue:exception.name forKey:NSLocalizedDescriptionKey];
*error = [NSError errorWithDomain:@"somedomain" code:100 userInfo:details];
return FALSE;
}
}
@end
现在,我只是(在我的Swift代码中):
do{
//starPort.getParsedStatus(status ,2)
try starPort.getParsedStatusThrowing(status, level: 2)
defer{
// Release the port in any case.
SMPort.releasePort(starPort)
}
}catch{
print(error)
// do staff like return
}
非常感谢!
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