Zebra藍牙打印機只能在調試器下工作

Question

我正在打印到QLn420，它在調試器下工作良好，或者只有極少量的ZPL傳遞給它，但當我運行不在調試器下的應用程序時，它失敗。代碼與Zebra的演示代碼（https://km.zebra.com/kb/index?page=content&id=WH122&actp=LIST）基本相同，不同之處在於dispatch_async在調用堆棧中較早執行。

NSString *serialNumber = [ZebraPrintManager getBluetoothSerial]; 

// Instantiate connection to Zebra Bluetooth accessory 
id<ZebraPrinterConnection, NSObject> thePrinterConn = [[MfiBtPrinterConnection alloc] initWithSerialNumber:serialNumber]; 

// Open the connection - physical connection is established here. 
BOOL success = [thePrinterConn open]; 

NSError *error = nil; 

// Send the data to printer as a byte array. 
NSData* data = [ZPL dataUsingEncoding:NSUTF8StringEncoding]; 
success = success && [thePrinterConn write:data error:&error]; 

dispatch_async(dispatch_get_main_queue(), ^{ 
    if(success != YES || error != nil) { 
     UIAlertView *errorAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:[error localizedDescription] delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil]; 
     [errorAlert show]; 
    } 
}); 

// Close the connection to release resources. 
[thePrinterConn close]; 

Answer 1

藍牙有延遲設置。將此增加到至少100.某些電話不能使用設置爲30的值。