連接Blutooth低能量設備。如何等待BluetoothGattCallback方法完成

Question

我是Android的新手，並且我有一個項目將Android設備與其他設備連接到BLE。連接後我有mBluetoothGatt.discoverServices()，我需要在調用onServicesDiscovered之後致電mBluetoothGatt.getServices()。現在我使用這個代碼：

@Override 
public void onServicesDiscovered(BluetoothGatt gatt, int status) { 
    if(status == BluetoothGatt.GATT_SUCCESS){ 
     servicesFound = true; 
     Log.i("Send", String.valueOf(gatt.getServices().size())); 
    } 
} 

，這是在點擊按鈕：

public void btnTestWriteOnClick(View v){ 
    if(mBluetoothGatt != null) { 
     mBluetoothGatt.discoverServices(); 

     byte[] allBytesToSend = new byte[]{...};//Test byte array. 

     List<BluetoothGattService> serviceList = mBluetoothGatt.getServices(); 
     while(!servicesFound){ 

     } 
     servicesFound = false; 
     displayGattServicesTest(serviceList, allBytesToSend); 
    } 
}  

編輯

我displayGattServicesTest：

private void displayGattServicesTest(List<BluetoothGattService> gattServices, byte[] allBytesToSend) { 
    if (gattServices == null) return; 
    //Sets the interval for printing. 
    //ChangeIntervalAndTimeout(); 

    // Enable notification for characteristic. 
    EnableNotificationInFFF4(gattServices); 

    // Loops through available GATT Services. 
    for (BluetoothGattService gattService : gattServices) { 
     if (gattService.getUuid().toString().contains(serviceUUID)) { 
      for (final BluetoothGattCharacteristic characteristic : gattService.getCharacteristics()) { 
       if (characteristic.getUuid().toString().contains(characUUID)) { 

        long startTime = System.currentTimeMillis(); 
        Log.i("Send", "===========================BEGINNING==========================="); 

        int size = 19; 
        int times = allBytesToSend.length/size; 
        if (allBytesToSend.length > times * size) { 
         times++; 
        } 

        params = new byte[times][]; 
        int tmp; 
        for (tmp = 0; tmp < 1000; tmp++) { 
         int logCount = 0; 
         for (int i = 0; i < allBytesToSend.length; i++) { 
          if(allBytesToSend.length < i + size){ 
           size = allBytesToSend.length - i; 
          } 
          params[logCount] = new byte[size]; 
          System.arraycopy(allBytesToSend, i, params[logCount], 0, size); 
          i += size - 1; 
          Log.i("Send", "====Sending command No " + logCount + "===="); 
          logCount++; 
         } 
         WriteIntoPrinter t = new WriteIntoPrinter(characteristic); 
         t.execute(params); 

         try { 
          t.get(2000, TimeUnit.MILLISECONDS); 
         } catch (InterruptedException | ExecutionException | TimeoutException e) { 
          e.printStackTrace(); 
          t.cancel(true); 
          break; 
         } 
        } 

        Log.i("Send", "===========================DONE==========================="); 
        Log.i("Send", "Tmp = " + tmp); 
        long difference = System.currentTimeMillis() - startTime; 
        Log.i("Send", "Time - " + (double) (difference/1000) + " sec."); 
        break; 
       } 
      } 
      break; 
     } 
    } 
} 

我的AsyncTask：

private class WriteIntoPrinter extends AsyncTask<byte[], Void, Void>{ 
    BluetoothGattCharacteristic characteristic; 

    WriteIntoPrinter(BluetoothGattCharacteristic characteristic){ 
     this.characteristic = characteristic; 
     //characteristic.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE); 
    } 

    @Override 
    protected Void doInBackground(final byte[]... params) { 
     for (int i = 0; i < params.length ; i++) { 
      Log.i("Send", "Sending - " + i + " part. Number of bytes: " + params[i].length); 
      characteristic.setValue(params[i]); 
      mBluetoothGatt.writeCharacteristic(characteristic); 

      final int finalI = i; 
      Thread t = new Thread(new Runnable() { 
       @Override 
       public void run() { 
        if (finalI == params.length - 1) { 
         Log.i("Send", "WaitingThread final - " + finalI); 
         while (!isWritingOnPaper) { 
          //SystemClock.sleep(20); 
         } 
         Log.i("Send", "WaitingThread final - " + finalI + " Done."); 
        } 
        else{ 
         while (!isSuccessful) { 
          //SystemClock.sleep(20); 
         } 
        } 
       } 
      }); 

      t.start(); 
      try { 
       t.join(); // wait for thread to finish 
      } catch (InterruptedException e) { 
       e.printStackTrace(); 
      } 
      isWritingOnPaper = false; 
      isSuccessful = false; 
     } 

     return null; 
    } 
} 

NOTE這只是一個測試，不介意for循環和AsyncTask中的新線程。在displayGattServicesTest的Basecally中，我將byte[]分成19個字節的數組併發送1000次以測試速度。

注2 Dept描述：displayGattServicesTest採取byte[]，這正好是4 * 19字節長。之後，它將生成byte[4][19]，並將byte[4][19]賦給AsyncTask，該AsyncTask開始寫入特徵。每次等待onCharacteristicWrite返回true，當它寫入最後一個[19]字節時，等待onCharacteristicChanged返回true，然後寫入下一個byte[4][19]。這是目標。

我在閱讀和寫作時也會這麼想。

這是行得通的，但我不認爲這是正確的做法。 :)有沒有其他方式可以等待onServicesDiscovered,onCharacteristicWrite和onCharacteristicChanged成功完成。

Answer 1

在你btnTestWriteOnClick只是顯示進度條，然後等待結果onServicesDiscovered，如果你有結果，那麼隱藏進度條，做你的東西（叫displayGattServicesTest在onServicesDiscovered），你可以在發現是禁用按鈕阻止用戶點擊並開始新發現。