title: How to get the characteristic from UUID in objective-C?
body: <p>I am developing for BLE in objective-C.</p>
  
  <p>I define the UUID like the following code:</p>
  
  <pre><code>    static NSString *const LEDStateCharacteristicUUID = @"ffffffff-7777-7uj7-a111-d631d00173f4";
  </code></pre>
  
  <p>I want to write characteristic to BLE device by following code , it need to pass 3 parameter:1.Data  2.Characteristic  3.type </p>
  
  <pre><code>CBCharacteristic *chara = ??? // how to set the characteristic via above UUID let it can pass to following function?
  
  [peripheral writeValue:data forCharacteristic:chara type:CBCharacteristicWriteWithoutResponse];
  </code></pre>
  
  <p>How to set the characteristic via above UUID let it can pass to <code>writeCharacteristic</code> function?</p>
  
  <p>Thanks in advance.</p>