CODEWITHSUNDEEP
androidqr-code
Vijayachandran Chettiar
Vijayachandran Chettiar

Reputation: 69

How to start QR scanner immediately upon starting the application?

My code for QR code scanning is given below:

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        //View objects
        buttonScan = findViewById<View>(R.id.buttonScan) as Button
        textViewName = findViewById<View>(R.id.textViewName) as TextView
        textViewAddress = findViewById<View>(R.id.textViewAddress) as TextView

        //intializing scan object
        qrScan = IntentIntegrator(this)

        //attaching onclick listener
        buttonScan!!.setOnClickListener(this)


    }

    //Getting the scan results
    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent) {
        val result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data)
        if (result != null) {
            //if qrcode has nothing in it
            if (result.contents == null) {
                Toast.makeText(this, "Result Not Found", Toast.LENGTH_LONG).show()
            } else {
                //if qr contains data
                try {

                    //converting the data to json
                    val obj = JSONObject(result.contents)
                    //setting values to textviews
                    textViewName!!.text = obj.getString("busno")

                    textViewAddress!!.text = obj.getString("busname")


                } catch (e: JSONException) {
                    e.printStackTrace()
                    //if control comes here
                    //that means the encoded format not matches
                    //in this case you can display whatever data is available on the qrcode
                    //to a toast
                    Toast.makeText(this, result.contents, Toast.LENGTH_LONG).show()
                }

            }
        } else {
            super.onActivityResult(requestCode, resultCode, data)
        }
    }

    override fun onClick(view: View) {
        //initiating the qr code scan
        qrScan!!.initiateScan()
    }

The QR code scanner starts after I press the button declared as buttonScan. How do I start the QR scanner immediately after the application is opened and then display the scan details? Does it require a new activity?

I have used ZXING library for implementing the scanner.

Thank you!

Upvotes: 1

Views: 94

Answers (1)

Gratien Asimbahwe
Gratien Asimbahwe

Reputation: 1614

With your code you can start the QR Scanner in two ways:

the first way is to initiate scan directly after this qrScan = IntentIntegrator(this)

so your onCreate can be:

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        //View objects
        buttonScan = findViewById<View>(R.id.buttonScan) as Button
        textViewName = findViewById<View>(R.id.textViewName) as TextView
        textViewAddress = findViewById<View>(R.id.textViewAddress) as TextView

        //intializing scan object
        qrScan = IntentIntegrator(this)

        //initiate scan directly
        qrScan!!.initiateScan()

        //attaching onclick listener
        buttonScan!!.setOnClickListener(this)


    }

The second way is to trigger the click event to the buttonScan and it will initiatiate scan directly.

buttonScan!!.callOnClick

Upvotes: 1

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