I want to read NFC tag data only while I press the button on Android.

techlist=arrayOf(
            arrayOf (android.nfc.tech.NfcA::class.java.name),
            arrayOf (android.nfc.tech.NfcB::class.java.name),
            arrayOf (android.nfc.tech.IsoDep::class.java.name),
            arrayOf (android.nfc.tech.MifareClassic::class.java.name),
            arrayOf (android.nfc.tech.NfcV::class.java.name),
            arrayOf (android.nfc.tech.NfcF::class.java.name),
            arrayOf (android.nfc.tech.NdefFormatable::class.java.name),
            arrayOf (android.nfc.tech.MifareUltralight::class.java.name)
        )

nfc_adapt!!.enableReaderMode(this, {t->
                        tview!!.text=t.toString()
                        tview!!.setBackgroundColor(Color.YELLOW)
                        tview!!.setTextColor(Color.rgb(0,0,0))
                        nfc_adapt!!.disableReaderMode(this)
                        read_button!!.isEnabled=false//disable read button until user push the delete button
                        delete_button!!.isEnabled=true

                    },(
                            NfcAdapter.FLAG_READER_SKIP_NDEF_CHECK or
                            NfcAdapter.FLAG_READER_NFC_A or
                            NfcAdapter.FLAG_READER_NFC_Bor
                            NfcAdapter.FLAG_READER_NFC_BARCODE or
                            NfcAdapter.FLAG_READER_NFC_For
                            NfcAdapter.FLAG_READER_NFC_V
                            ),
                    null)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.youtube_dler">
    <uses-permission android:name="android.permission.NFC">/uses-permission>
    <application
        android:allowBackup="true"
        android: icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android: roundIcon="@mipmap/ic_launcher_round"
        android:supportRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>

</manifest>

class MainActivity:AppCompatActivity(){
    var pendingintent —PendingIntent?= null
    varnfc_adapt —NfcAdapter ?= null
    variFilter:IntentFilter?= null
    vartview —TextView?= null
    var read_button —Button?=null // Button to press when loading
    var delete_button —Button?=null//Press button to erase TextView (tview) contents
    @SuppressLint ("ClickableViewAccessibility")
    override fun onCreate (savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        tview=findViewById(R.id.textView) // TextView for display
        nfc_adapt = NfcAdapter.getDefaultAdapter (applicationContext)
        pendingIntent=PendingIntent.getActivity(this,0,Intent(this,javaClass).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP),0
        )
        iFilter=IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED)
        valiFilters=arrayOf<IntentFilter> (iFilter!!)

        read_button=findViewById (R.id.button)
        delete_button=findViewById (R.id.button2)
        delete_button!!.isEnabled=false

        read_button!!.setOnTouchListener(fun(v:View, m:MotionEvent): Boolean{
            when(m.action){
                MotionEvent.ACTION_DOWN->{
                    tview!!.setBackgroundColor(Color.rgb(0,0,0))
                    tview!!.setTextColor(Color.rgb(0,255,0))
                    tview!!.text="Now Reading A Tag"
                    Log.d(null, "ACTION UPPED")
                    nfc_adapt!!.enableForegroundDispatches(this,pendintent,iFilters,null)
                    return false
                }
                MotionEvent.ACTION_UP->{
                    nfc_adapt!!.disableForegroundDispatches(this)
                    US>tview!!.text="
                    return false
                }
            }
            return false
        })

        // Delete contents of TextView

        delete_button!!.setOnClickListener{
            US>tview!!.text="
            tview!!.setBackgroundColor(Color.rgb(0,0,0))
            tview!!.setTextColor(Color.rgb(0,255,0))
            read_button!!.isEnabled=true
            it.isEnabled=false
        }

    }

    override fun onNewIntent(intent:Intent) {
        super.onNewIntent(intent)
        valaction —String?=intent.action
        if(action.equals(NfcAdapter.ACTION_TECH_DISCOVERED)){
            varnfc_tag_array=intent.getParcelableArrayExtra(NfcAdapter.EXTRA_TAG)
            if(nfc_tag_array==null){
                tvview?.setBackgroundColor(Color.YELLOW)
                tview?.setTextColor(Color.rgb(0,0,0))
                tvview?.text="read a tag but does not contain tag data"
                return
            }
            valt=nfc_tag_array[0]as Tag?
            if(t==null){
                tview!!.text="Read a tag but it a null"
            } else{
                tview!!.text=t.toString()// Display TAG contents (not data) as a string
            }
            tview!!.setBackgroundColor(Color.YELLOW)
            tview!!.setTextColor(Color.rgb(0,0,0))
            nfc_adapt!!.disableForegroundDispatches(this)
            read_button!!.isEnabled=false//Disable the read button once you read it so that you can read it again when delete_button is pressed
            delete_button!!.isEnabled=true


        }
        else{
            // nothing to do
        }
    }

}