bluetooth scan not working android studio api 29

I have an app made with android studio that connects to my propitiatory wind gauge that I developed. everything was working perfectly until I submitted it to google. They rejected it saying i need targetSdkVersion 29. when I build it with targetSdkVersion 29 the app no longer scans. But it works when I build it with targetSdkVersion 26

AndroidManifest.xml

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.windgauge"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />
    <uses-feature
        android:name="android.hardware.bluetooth_le"
        android:required="true" />
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.windgauge.ScanActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="com.windgauge.DeviceActivity"    android:label="@string/app_name"     />
    </application>
</manifest>

ScanActivity.java

    package com.windgauge;

import android.Manifest;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.windgauge.util.BleUtil;
import com.windgauge.util.ScannedDevice;

import java.util.ArrayList;

import permissions.dispatcher.NeedsPermission;
import permissions.dispatcher.RuntimePermissions;

@RuntimePermissions
public class ScanActivity extends AppCompatActivity implements BluetoothAdapter.LeScanCallback {
    private BluetoothAdapter mBTAdapter;
    private DeviceAdapter mDeviceAdapter;
    private boolean mIsScanning;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        setContentView(R.layout.activity_scan);
        Button scan = findViewById(R.id.scan);
        scan.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ScanActivityPermissionsDispatcher.startScanWithPermissionCheck(ScanActivity.this);
            }
        });
        init();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        stopScan();
    }


    @Override
    public void onLeScan(final BluetoothDevice newDeivce, final int newRssi,
                         final byte[] newScanRecord) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mDeviceAdapter.update(newDeivce, newRssi, newScanRecord);
            }
        });
    }

    private void init() {
        // BLE check
        if (!BleUtil.isBLESupported(this)) {
            Toast.makeText(this, R.string.ble_not_supported, Toast.LENGTH_SHORT).show();
            finish();
            return;
        }

        // BT check
        BluetoothManager manager = BleUtil.getManager(this);
        if (manager != null) {
            mBTAdapter = manager.getAdapter();
        }
        if (mBTAdapter == null) {
            Toast.makeText(this, R.string.bt_unavailable, Toast.LENGTH_SHORT).show();
            finish();
            return;
        }
        if (!mBTAdapter.isEnabled()) {
            Toast.makeText(this, R.string.bt_disabled, Toast.LENGTH_SHORT).show();
            finish();
            return;
        }

        // init listview
        ListView deviceListView = (ListView) findViewById(R.id.list);
        mDeviceAdapter = new DeviceAdapter(this, R.layout.listitem_device,
                new ArrayList<ScannedDevice>());
        deviceListView.setAdapter(mDeviceAdapter);
        deviceListView.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterview, View view, int position, long id) {
                ScannedDevice item = mDeviceAdapter.getItem(position);
                if (item != null) {
                    Intent intent = new Intent(view.getContext(), DeviceActivity.class);
                    BluetoothDevice selectedDevice = item.getDevice();
                    intent.putExtra(DeviceActivity.EXTRA_BLUETOOTH_DEVICE, selectedDevice);
                    startActivity(intent);

                    // stop before change Activity
                    stopScan();
                }
            }
        });

        stopScan();
    }

    @NeedsPermission(Manifest.permission.ACCESS_COARSE_LOCATION)
    void startScan() {
        if ((mBTAdapter != null) && (!mIsScanning)) {
            mBTAdapter.startLeScan(this);
            mIsScanning = true;
            setProgressBarIndeterminateVisibility(true);
            invalidateOptionsMenu();
        }
    }

    private void stopScan() {
        if (mBTAdapter != null) {
            mBTAdapter.stopLeScan(this);
        }
        mIsScanning = false;
        setProgressBarIndeterminateVisibility(false);
        invalidateOptionsMenu();
    }
}