Persistent bluetooth connection about react-native-bluetooth-escpos-printer

[januslo]

here's the code for reference:

/**
     * Start the ConnectThread to initiate a connection to a remote device.
     *
     * @param device The BluetoothDevice to connect
     */
    public synchronized void connect(BluetoothDevice device) {
        if (DEBUG) Log.d(TAG, "connect to: " + device);
        BluetoothDevice connectedDevice = null;
        if(mConnectedThread!=null){
            connectedDevice = mConnectedThread.bluetoothDevice();
        }
        if( mState==STATE_CONNECTED && connectedDevice!=null && connectedDevice.getAddress().equals(device.getAddress())){
            // connected already
            Map<String, Object> bundle = new HashMap<String, Object>();
            bundle.put(DEVICE_NAME, device.getName());
            bundle.put(DEVICE_ADDRESS,device.getAddress());
            setState(STATE_CONNECTED, bundle);
        }else {
            // Cancel any thread currently running a connection
            this.stop();
            // Start the thread to manage the connection and perform transmissions
            mConnectedThread = new ConnectedThread(device);
            mConnectedThread.start();
            setState(STATE_CONNECTING, null);
        }
    }

[januslo]

yeah, to keep this works, plz update to version 0.0.3 as soon as it's published laster on.

[januslo]

Plz use the master branch directly , keep the last connected device in the localstorage or global vars ,then call connect() again would just resume the connection as long as it's the same one.

[firdaussoberi]

Thanks for the suggestions! I got it to work. For anyone watching this, for example, in the examples/App.js inside render there is a block like so:

/*some code*/
BluetoothManager.connect(rowData.address)
 .then((s)=>{
   this.setState({
    loading:false,
    boundAddress:rowData.address, 
    name:rowData.name || rowData. address
})
    alert(s);
    AsyncStorage.setItem("lastDevice", JSON.stringify(rowData));   //add here
},(e)=>{
   this.setState({
     loading:false
 })
   alert(e);
}

/*some code*/

Then I define a function reconnectDevice() with promise to AsyncStorage.getItem from "lastDevice" then BluetoothManager.connect(address)

reconnectDevice = () => {
    new Promise((resolve, reject) => {
    AsyncStorage.getItem("lastDevice")  
      .then(res => {
        if (res !== null ) {			
          resolve(true);

          BluetoothManager.connect(JSON.parse(res).address).then((s)=>{
          this.setState({
          loading:false,
          boundAddress:JSON.parse(res).address,
          name:JSON.parse(res).name || JSON.parse(res).address
          })
		    /*for debugging*/
            //alert("Connected again! Device: " + s + ", name is: " + JSON.parse(res).name + ", address is: " + JSON.parse(res).address );
          },(e)=>{
              this.setState({
              loading:false
               })
              //alert(e);
			  //alert("Hi :"  + e);
			  console.log(e);
            })	
			
			this.setState({
                deviceAddress: JSON.parse(res).address,
                isLoading_reconnect:false,
                });		  
		  //alert("Result reconnect is: " + res);
        } else {
          resolve(false);
		  //alert("Result reconnect is: " + res);
        }
      })
      .catch(err => {reject(err); alert("Failed to get data. Contact admin");});
    });
	}

Finally I call it as

componentDidMount(){
this.reconnectDevice();
}

This may not be clean, but it solves my problem (at the moment). Thanks.