Android 6.0 Kotlin 蓝牙BLE扫描（改为指定时间没有发现新设备后停止扫描）

package com.arci.myapplication

import android.os.Bundle
import android.support.design.widget.Snackbar
import android.support.v7.app.AppCompatActivity
import android.view.Menu
import android.view.MenuItem
import android.view.View

import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.android.synthetic.main.content_main.*
import android.bluetooth.BluetoothManager
import android.content.Context
import android.bluetooth.BluetoothAdapter
import android.widget.Toast
import android.content.Intent
import android.bluetooth.BluetoothDevice
import android.bluetooth.le.BluetoothLeScanner
import android.bluetooth.le.ScanCallback
import android.bluetooth.le.ScanResult
import android.os.Handler

class MainActivity : AppCompatActivity() {
    private val REQUEST_BLUETOOTH_TURN_ON = 1
    private lateinit var bleAdapter: BluetoothAdapter
    private lateinit var bleManager: BluetoothManager
    private lateinit var bleScanner: BluetoothLeScanner
    private lateinit var bleScanCallback: BleScanCallback
    private var bleScanResults = mutableMapOf<String?, BluetoothDevice?>()

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

        fab.setOnClickListener { view ->
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show()
        }
        //蓝牙管理，这是系统服务可以通过getSystemService(BLUETOOTH_SERVICE)的方法获取实例
        bleManager = getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
        //通过蓝牙管理实例获取适配器，然后通过扫描方法（scan）获取设备(device)
        bleAdapter = bleManager.adapter
        if (!bleAdapter.isEnabled) {
            val bluetoothTurnOn = Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE)
            startActivityForResult(bluetoothTurnOn, REQUEST_BLUETOOTH_TURN_ON)
        } else {
            bleStartScan.run()
        }
    }

    //start scan
    private val bleStartScan = Runnable {
        bleScanner = bleAdapter.bluetoothLeScanner
        bleScanCallback = BleScanCallback(bleScanResults)
        bleScanCallback.setContext(this.applicationContext)
        bleScanCallback.setStopScan(this.bleStopScan)
        bleScanner.startScan(bleScanCallback)
        Toast.makeText(this.applicationContext, "蓝牙BLE扫描开始", Toast.LENGTH_SHORT).show()
        bleScanCallback.scanHandler.postDelayed(bleStopScan, bleScanCallback.SCAN_PERIOD)
    }

    private val bleStopScan = Runnable {
        if (bleScanner != null) {
            bleScanner.stopScan(bleScanCallback)
        }
        Toast.makeText(this.applicationContext, "蓝牙BLE扫描结束", Toast.LENGTH_SHORT).show()
    }

    class BleScanCallback(resultMap: MutableMap<String?, BluetoothDevice?>) : ScanCallback() {
        val SCAN_PERIOD : Long = 10000
        var resultOfScan = resultMap
        private var context: Context? = null
        private var stopScan: Runnable? = null
        var scanHandler = Handler()

        fun setContext(context: Context) {
            this.context = context
        }

        fun setStopScan(runnable: Runnable) {
            this.stopScan = runnable
        }

        override fun onScanResult(callbackType: Int, result: ScanResult?) {
            addScanResult(result)
        }

        override fun onBatchScanResults(results: MutableList<ScanResult>?) {
            results?.forEach { result -> addScanResult(result) }
        }

        override fun onScanFailed(errorCode: Int) {
            Toast.makeText(this.context, "蓝牙BLE扫描失败" + "Error Code: " + errorCode, Toast.LENGTH_SHORT).show()
        }

        fun addScanResult(scanResult: ScanResult?) {
            val bleDevice = scanResult?.device
            val deviceAddress = bleDevice?.address
            if (!resultOfScan.contains(deviceAddress)) {
                resultOfScan.put(deviceAddress, bleDevice)
                if (this.context != null) {
                    Toast.makeText(this.context, bleDevice?.name + ": " + bleDevice?.address, Toast.LENGTH_SHORT).show()
                }
                this.scanHandler.removeCallbacks(this.stopScan)
                this.scanHandler.postDelayed(this.stopScan, this.SCAN_PERIOD)
            }
        }
    }
    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        when (requestCode) {
            REQUEST_BLUETOOTH_TURN_ON->{
                when (resultCode) {
                    RESULT_OK->{
                        //TextView1.text = "蓝牙开启成功"
                        Toast.makeText(this.applicationContext, "蓝牙开启成功", Toast.LENGTH_SHORT).show()
                        bleStartScan.run()
                    }
                    RESULT_CANCELED->{
                        //TextView1.text = "蓝牙开启失败"
                        Toast.makeText(this.applicationContext, "蓝牙开启失败", Toast.LENGTH_SHORT).show()
                    }
                }
            }
        }
    }
    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        // Inflate the menu; this adds items to the action bar if it is present.
        menuInflater.inflate(R.menu.menu_main, menu)
        return true
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        return when (item.itemId) {
            R.id.action_settings -> true
            else -> super.onOptionsItemSelected(item)
        }
    }
}