android bluetooth 搜尋距離

【实例截图】

【核心代码】

package com.example.weichen.afinal;


import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.bluetooth.BluetoothManager;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;




public class MainActivity extends AppCompatActivity {
    private Button btn, btn2;
    private TextView textView;
    private ListView scanlist;
    private ArrayList<String> deviceName; //用來裝搜尋到的設備名稱
    private ListAdapter listAdapter;      //等等用來將listView綁上Adapter

    private BluetoothManager bluetoothManager;
    private BluetoothAdapter mBluetoothAdapter;
    private static final String TAG = "mylogggg";
    private ArrayList<BluetoothDevice> mBluetoothDevices = new ArrayList<BluetoothDevice>();
    ArrayAdapter<String> btArrayAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn = (Button) findViewById(R.id.btn_find); //按鈕打開藍芽
        btn2 = (Button) findViewById(R.id.button2); //按鈕偵測
        textView = (TextView) findViewById(R.id.textView);
        scanlist = (ListView) findViewById(R.id.mListView);
        btn.setOnClickListener(mybtn1);
        btn2.setOnClickListener(mybtn2);



        //ListView相關宣告
        deviceName = new ArrayList<String>();
        listAdapter = new ArrayAdapter<String>(getBaseContext(),
android.R.layout.simple_expandable_list_item_1, deviceName);//ListView使用的Adapter，
//listAdapter一定要先new出來，才能做setAdapter ////將listView綁上Adapter
        scanlist.setAdapter(listAdapter); 

        System.out.println(deviceName);
    }

    //『是否開啟藍芽』    (沒問題)
    private Button.OnClickListener mybtn1 = new Button.OnClickListener() {
        @Override
        public void onClick(View v) {
            //得到 BluetoothAdapter對象
            BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
            //判斷 BluetoothAdapter 對象是否為空，若空則表示本機無藍芽設備
            if (adapter == null) {
                Toast toast = Toast.makeText(MainActivity.this, "本機無藍芽設備", Toast.LENGTH_SHORT);
                toast.show();
            }
            /*if (!adapter.isEnabled()) {
                //用Intent提示使用者開啟藍芽 (用Intent從APP本身要求開啟)
                Intent in = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
                startActivity(in);
                Toast toast = Toast.makeText(MainActivity.this, "已經開藍芽了", Toast.LENGTH_SHORT);
                toast.show();
            }*/
            /* 下面三行 為了讓mBluetoothAdapter.enable()不會crash ，所以需要*/
            bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
                mBluetoothAdapter = bluetoothManager.getAdapter();
            }
            if (mBluetoothAdapter.enable()) { //(從系統本身要求開啟)
                Toast toast = Toast.makeText(MainActivity.this, "已經開啟藍芽了", Toast.LENGTH_SHORT);
                toast.show();
            }
        }
    };


    private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {
        @Override
        public void onLeScan(final BluetoothDevice device, final int rssi, byte[] scanRecord) {
            runOnUiThread(new Runnable() { 
//使用runOnUiThread方法，其功能等同於WorkThread透過Handler將資訊傳到MainThread(UiThread)中，
                //詳細可進到runOnUiThread中觀察
                @Override
                public void run() {
                    if (!mBluetoothDevices.contains(device)) { //利用contains判斷是否有搜尋到重複的device
                        mBluetoothDevices.add(device);         //如沒重複則添加到bluetoothdevices中
//將device的Name、rssi、address裝到此ArrayList<Strin>中
                        deviceName.add(device.getName() " rssi:" rssi "\r\n" device.getAddress()); 
//使用notifyDataSetChanger()更新listAdapter的內容
                        ((BaseAdapter) listAdapter).notifyDataSetChanged();
                    }
                }
            });
        }


    };
    private final BroadcastReceiver ActionFoundReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            // TODO Auto-generated method stub
            String action = intent.getAction();
            if (BluetoothDevice.ACTION_FOUND.equals(action)) {

                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                short rssi = intent.getShortExtra(BluetoothDevice.EXTRA_RSSI, Short.MIN_VALUE);
                btArrayAdapter.add("Name: " device.getName() "\n" "Address: " device.getAddress()
"\n" "rssi: " rssi " dBm");
                btArrayAdapter.notifyDataSetChanged();
            }
        }
    };

    private Button.OnClickListener mybtn2 = new Button.OnClickListener(){

        @Override
        public void onClick(View v) {

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
                mBluetoothAdapter.startLeScan(mLeScanCallback);//跳到mLeScanCallback開始搜尋BLE設備
            }
            textView.setText("Scanning");
            Log.d(TAG, "Start Scan");
            System.out.println(deviceName);


        }
    };

}