Android enables Bluetooth devices to detect connections

2020-02-13 • Android

Both WiFi and 4G networks access Internet resources after establishing a network connection, and can not directly access LAN resources. For example, when two people are together, a should transmit the video on the mobile phone to B. usually, it is to open the mobile phone QQ and transmit files to each other through QQ. However, uploading videos consumes a lot of traffic. What if there is no WiFi available on site and the data traffic on the mobile phone is insufficient? In order to solve the problem of transferring files nearby, Bluetooth technology came into being. Bluetooth technology is a wireless technology standard, which can realize short-distance data exchange between devices.

Android provides four tool classes for Bluetooth technology, namely Bluetooth adapter, Bluetooth device, Bluetooth server socket and Bluetooth client socket.

Bluetooth adapter

The function of Bluetooth adapter is similar to that of other * * mangers. You can use it as a Bluetooth manager. The following is a description of common methods of Bluetooth adapter.

Getdefaultadapter: static method to obtain the default Bluetooth adapter object; Enable: turn on Bluetooth function; Disable: turn off Bluetooth function; Isenable: judge whether the Bluetooth function is turned on; Startdiscovery: start searching the surrounding Bluetooth devices; Canceldiscovery: cancels the search operation; Isdiscovering: judge whether the device is currently being searched; Getbondeddevices: get the bound device list; Setname: set the Bluetooth name of this computer; Getname: get the Bluetooth name of this machine; Getaddress: get the Bluetooth address of the machine; Getremotedevice: obtain the remote Bluetooth device according to the Bluetooth address; Getstate: get the status of the local Bluetooth adapter; Listenusingrfcommwithservicerecord: creates and returns a Bluetooth servicesocket according to the name and UUID; Listenusingrfcommon: creates and returns a Bluetooth service socket according to the channel number.

Bluetooth devicebluetooth device

Bluetooth device refers to a Bluetooth device, usually the other device. Bluetooth adapter manages native Bluetooth devices. The following is a description of common methods of Bluetooth device.

Bluetooth server socket

Bluetooth service socket is the socket of the server, which is used to receive socket connection requests from the client. The following is a description of common methods.

Accept: listen for external Bluetooth connection requests; Close: turn off Bluetooth monitoring on the server.

Bluetooth client socket

Bluetooth socket is the socket of the client, which is used for data communication with the other device. The following is a description of common methods.

layout\activity_ Bluetooth.xml interface layout code is as follows:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  android:padding="5dp">

  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <Check@R_382_2419@
      android:id="@+id/ck_bluetooth"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:button="@null"
      android:checked="false"
      android:drawableLeft="@drawable/ck_status_selector"
      android:text="蓝牙"
      android:textColor="#ff000000"
      android:textSize="17sp" />

    <TextView
      android:id="@+id/tv_discovery"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1"
      android:gravity="right|center"
      android:textColor="#ff000000"
      android:textSize="17sp" />
  </LinearLayout>

  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:orientation="horizontal">

    <TextView
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="4"
      android:gravity="center"
      android:text="名称"
      android:textColor="#ff000000"
      android:textSize="17sp" />

    <TextView
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="5"
      android:gravity="center"
      android:text="地址"
      android:textColor="#ff000000"
      android:textSize="17sp" />

    <TextView
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="2"
      android:gravity="center"
      android:text="状态"
      android:textColor="#ff000000"
      android:textSize="17sp" />
  </LinearLayout>

  <ListView
    android:id="@+id/lv_bluetooth"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

</LinearLayout>

The logical code of bluetoothactivity.java is as follows:

package com.fukaimei.bluetoothtest;

import java.io.IOException;
import java.lang.reflect.Method;
import java.util.ArrayList;

import android.app.AlertDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Check@R_382_2419@;
import android.widget.CompoundButton;
import android.widget.ListView;
import android.widget.CompoundButton.OnCheckedchangelistener;
import android.widget.TextView;
import android.widget.Toast;

import com.fukaimei.bluetoothtest.adapter.Bluelistadapter;
import com.fukaimei.bluetoothtest.bean.BlueDevice;
import com.fukaimei.bluetoothtest.task.BlueAcceptTask;
import com.fukaimei.bluetoothtest.task.BlueConnectTask;
import com.fukaimei.bluetoothtest.task.BlueReceiveTask;
import com.fukaimei.bluetoothtest.util.BluetoothUtil;
import com.fukaimei.bluetoothtest.widget.InputDialogFragment;

public class BluetoothActivity extends AppCompatActivity implements
    OnClickListener,OnItemClickListener,OnCheckedchangelistener,BlueConnectTask.BlueConnectListener,InputDialogFragment.InputCallbacks,BlueAcceptTask.BlueAcceptListener {
  private static final String TAG = "BluetoothActivity";
  private Check@R_382_2419@ ck_bluetooth;
  private TextView tv_discovery;
  private ListView lv_bluetooth;
  private BluetoothAdapter mBluetooth;
  private ArrayList<BlueDevice> mDeviceList = new ArrayList<BlueDevice>();

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_bluetooth);
    bluetoothPermissions();
    ck_bluetooth = (Check@R_382_2419@) findViewById(R.id.ck_bluetooth);
    tv_discovery = (TextView) findViewById(R.id.tv_discovery);
    lv_bluetooth = (ListView) findViewById(R.id.lv_bluetooth);
    if (BluetoothUtil.getBlueToothStatus(this) == true) {
      ck_bluetooth.setChecked(true);
    }
    ck_bluetooth.setOnCheckedchangelistener(this);
    tv_discovery.setOnClickListener(this);
    mBluetooth = BluetoothAdapter.getDefaultAdapter();
    if (mBluetooth == null) {
      Toast.makeText(this,"本机未找到蓝牙功能",Toast.LENGTH_SHORT).show();
      finish();
    }
  }

  // 定义获取基于地理位置的动态权限
  private void bluetoothPermissions() {
    if (ContextCompat.checkSelfPermission(this,android.Manifest.permission.ACCESS_COARSE_LOCATION)
        != PackageManager.PERMISSION_GRANTED) {
      ActivityCompat.requestPermissions(this,new String[]{
          android.Manifest.permission.ACCESS_COARSE_LOCATION},1);
    }
  }

  /**
   * 重写onRequestPermissionsResult方法
   * 获取动态权限请求的结果,再开启蓝牙
   */
  @Override
  public void onRequestPermissionsResult(int requestCode,@NonNull String[] permissions,@NonNull int[] grantResults) {
    if (requestCode == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
      if (BluetoothUtil.getBlueToothStatus(this) == true) {
        ck_bluetooth.setChecked(true);
      }
      ck_bluetooth.setOnCheckedchangelistener(this);
      tv_discovery.setOnClickListener(this);
      mBluetooth = BluetoothAdapter.getDefaultAdapter();
      if (mBluetooth == null) {
        Toast.makeText(this,Toast.LENGTH_SHORT).show();
        finish();
      }
    } else {
      Toast.makeText(this,"用户拒绝了权限",Toast.LENGTH_SHORT).show();
    }
    super.onRequestPermissionsResult(requestCode,permissions,grantResults);
  }

  @Override
  public void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {
    if (buttonView.getId() == R.id.ck_bluetooth) {
      if (isChecked == true) {
        beginDiscovery();
        Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
        startActivityForResult(intent,1);
        // 下面这行代码为服务端需要，客户端不需要
        mHandler.postDelayed(mAccept,1000);
      } else {
        cancelDiscovery();
        BluetoothUtil.setBlueToothStatus(this,false);
        mDeviceList.clear();
        Bluelistadapter adapter = new Bluelistadapter(this,mDeviceList);
        lv_bluetooth.setAdapter(adapter);
      }
    }
  }

  private Runnable mAccept = new Runnable() {
    @Override
    public void run() {
      if (mBluetooth.getState() == BluetoothAdapter.STATE_ON) {
        BlueAcceptTask acceptTask = new BlueAcceptTask(true);
        acceptTask.setBlueAcceptListener(BluetoothActivity.this);
        acceptTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
      } else {
        mHandler.postDelayed(this,1000);
      }
    }
  };

  @Override
  public void onClick(View v) {
    if (v.getId() == R.id.tv_discovery) {
      beginDiscovery();
    }
  }

  @Override
  protected void onActivityResult(int requestCode,int resultCode,Intent intent) {
    super.onActivityResult(requestCode,resultCode,intent);
    if (requestCode == 1) {
      if (resultCode == RESULT_OK) {
        Toast.makeText(this,"允许本地蓝牙被附近的其它蓝牙设备发现",Toast.LENGTH_SHORT).show();
      } else if (resultCode == RESULT_CANCELED) {
        Toast.makeText(this,"不允许蓝牙被附近的其它蓝牙设备发现",Toast.LENGTH_SHORT).show();
      }
    }
  }

  private Runnable mRefresh = new Runnable() {
    @Override
    public void run() {
      beginDiscovery();
      mHandler.postDelayed(this,2000);
    }
  };

  private void beginDiscovery() {
    if (mBluetooth.isDiscovering() != true) {
      mDeviceList.clear();
      Bluelistadapter adapter = new Bluelistadapter(BluetoothActivity.this,mDeviceList);
      lv_bluetooth.setAdapter(adapter);
      tv_discovery.setText("正在搜索蓝牙设备");
      mBluetooth.startDiscovery();
    }
  }

  private void cancelDiscovery() {
    mHandler.removeCallbacks(mRefresh);
    tv_discovery.setText("取消搜索蓝牙设备");
    if (mBluetooth.isDiscovering() == true) {
      mBluetooth.cancelDiscovery();
    }
  }

  @Override
  protected void onStart() {
    super.onStart();
    mHandler.postDelayed(mRefresh,50);
    blueReceiver = new BluetoothReceiver();
    //需要过滤多个动作，则调用IntentFilter对象的addAction添加新动作
    IntentFilter foundFilter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
    foundFilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
    foundFilter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
    registerReceiver(blueReceiver,foundFilter);
  }

  @Override
  protected void onStop() {
    super.onStop();
    cancelDiscovery();
    unregisterReceiver(blueReceiver);
  }

  private BluetoothReceiver blueReceiver;

  private class BluetoothReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context,Intent intent) {
      String action = intent.getAction();
      Log.d(TAG,"onReceive action=" + action);
      // 获得已经搜索到的蓝牙设备
      if (action.equals(BluetoothDevice.ACTION_FOUND)) {
        BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
        BlueDevice item = new BlueDevice(device.getName(),device.getAddress(),device.getBondState() - 10);
        mDeviceList.add(item);
        Bluelistadapter adapter = new Bluelistadapter(BluetoothActivity.this,mDeviceList);
        lv_bluetooth.setAdapter(adapter);
        lv_bluetooth.setOnItemClickListener(BluetoothActivity.this);
      } else if (action.equals(BluetoothAdapter.ACTION_DISCOVERY_FINISHED)) {
        mHandler.removeCallbacks(mRefresh);
        tv_discovery.setText("蓝牙设备搜索完成");
      } else if (action.equals(BluetoothDevice.ACTION_BOND_STATE_CHANGED)) {
        BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
        if (device.getBondState() == BluetoothDevice.BOND_BONDING) {
          tv_discovery.setText("正在配对" + device.getName());
        } else if (device.getBondState() == BluetoothDevice.BOND_BONDED) {
          tv_discovery.setText("完成配对" + device.getName());
          mHandler.postDelayed(mRefresh,50);
        } else if (device.getBondState() == BluetoothDevice.BOND_NONE) {
          tv_discovery.setText("取消配对" + device.getName());
        }
      }
    }
  }

  @Override
  public void onItemClick(AdapterView<?> parent,View view,int position,long id) {
    cancelDiscovery();
    BlueDevice item = mDeviceList.get(position);
    BluetoothDevice device = mBluetooth.getRemoteDevice(item.address);
    try {
      if (device.getBondState() == BluetoothDevice.BOND_NONE) {
        Method createBondMethod = BluetoothDevice.class.getmethod("createBond");
        Log.d(TAG,"开始配对");
        Boolean result = (Boolean) createBondMethod.invoke(device);
      } else if (device.getBondState() == BluetoothDevice.BOND_BONDED &&
          item.state != Bluelistadapter.CONNECTED) {
        tv_discovery.setText("开始连接");
        BlueConnectTask connectTask = new BlueConnectTask(item.address);
        connectTask.setBlueConnectListener(this);
        connectTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,device);
      } else if (device.getBondState() == BluetoothDevice.BOND_BONDED &&
          item.state == Bluelistadapter.CONNECTED) {
        tv_discovery.setText("正在发送消息");
        InputDialogFragment dialog = InputDialogFragment.newInstance(
            "","请输入要发送的消息");
        String fragTag = getResources().getString(R.string.app_name);
        dialog.show(getFragmentManager(),fragTag);
      }
    } catch (Exception e) {
      e.printStackTrace();
      tv_discovery.setText("配对异常：" + e.getMessage());
    }
  }

  //向对方发送消息
  @Override
  public void onInput(String title,String message,int type) {
    Log.d(TAG,"onInput message=" + message);
    Log.d(TAG,"mBlueSocket is " + (mBlueSocket == null ? "null" : "not null"));
    BluetoothUtil.writeOutputStream(mBlueSocket,message);
  }

  private BluetoothSocket mBlueSocket;

  //客户端主动连接
  @Override
  public void onBlueConnect(String address,BluetoothSocket socket) {
    mBlueSocket = socket;
    tv_discovery.setText("连接成功");
    refreshAddress(address);
  }

  //刷新已连接的状态
  private void refreshAddress(String address) {
    for (int i = 0; i < mDeviceList.size(); i++) {
      BlueDevice item = mDeviceList.get(i);
      if (item.address.equals(address) == true) {
        item.state = Bluelistadapter.CONNECTED;
        mDeviceList.set(i,item);
      }
    }
    Bluelistadapter adapter = new Bluelistadapter(this,mDeviceList);
    lv_bluetooth.setAdapter(adapter);
  }

  //服务端侦听到连接
  @Override
  public void onBlueAccept(BluetoothSocket socket) {
    Log.d(TAG,"onBlueAccept socket is " + (socket == null ? "null" : "not null"));
    if (socket != null) {
      mBlueSocket = socket;
      BluetoothDevice device = mBlueSocket.getRemoteDevice();
      refreshAddress(device.getAddress());
      BlueReceiveTask receive = new BlueReceiveTask(mBlueSocket,mHandler);
      receive.start();
    }
  }

  //收到对方发来的消息
  private Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      if (msg.what == 0) {
        byte[] readBuf = (byte[]) msg.obj;
        String readMessage = new String(readBuf,msg.arg1);
        Log.d(TAG,"handleMessage readMessage=" + readMessage);
        AlertDialog.Builder builder = new AlertDialog.Builder(BluetoothActivity.this);
        builder.setTitle("我收到消息啦").setMessage(readMessage).setPositiveButton("确定",null);
        builder.create().show();
      }
    }
  };

  @Override
  protected void onDestroy() {
    super.onDestroy();
    if (mBlueSocket != null) {
      try {
        mBlueSocket.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }
}

Add the corresponding permissions required for Bluetooth:

 <!-- 蓝牙 -->
  <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
  <uses-permission android:name="android.permission.BLUETOOTH" />
  <!--基于地理位置-->
  <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

The screenshot of demo program running effect interface is as follows:

The above is the whole content of this article. I hope it will help you in your study, and I hope you will support us a lot.

The content of this article comes from the network collection of netizens. It is used as a learning reference. The copyright belongs to the original author.

THE END

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