I used Bluetooth API and following code is for on/off, show paired devices list, and connect paired devices.
other functions work well, but connecting devices doesn't work .
I try to use thread bidirectional, when bluetooth turns on, serverthread(acceptthread) generated and started. And when I choose device on the list, clientthread(connectthread) generated and started. This is my intent, but when I try to connect on the phone, app is turned off(almost at the client, occasionally at the server).
I thought maybe it's UUID problem so I checked UUID 00enter code here001101-0000-1000-8000-00805F9B34FB, but it didn't help.enter code here
sorry for the import code chunks, I would really appreciate your help.
'''
package com.practice.bluetoothmodule;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.ExecutionException;
public class MainActivity extends AppCompatActivity {
TextView bthStatus;
Button bthOn;
Button bthOff;
Button bthCon;
BluetoothAdapter bthAdapter;
Set<BluetoothDevice> pairedDevices;
List<String> listofPairedDevices;
private String btAddress=null;
BluetoothDevice bthDevice;
AcceptThread acceptThread;
ConnectThread connectThread;
private Handler mHandler = null;
final static int BT_REQUEST_ENABLE=1;
final static UUID BT_UUID = UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bthStatus = (TextView)findViewById(R.id.text_check);
bthOn = (Button)findViewById(R.id.bth_on);
bthOff=(Button)findViewById(R.id.bth_off);
bthCon=(Button)findViewById(R.id.dev_con);
bthAdapter=BluetoothAdapter.getDefaultAdapter();
bthOn.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View view){
bluetoothOn();
}
});
bthOff.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View view){
bluetoothOff();
}
});
bthCon.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View view){
listPairedDevices();
}
});
}
@Override
public void onStart(){
super.onStart();
}
@Override
public void onDestroy(){
super.onDestroy();
if(acceptThread != null){
acceptThread.cancel();
acceptThread=null;
}
if(connectThread != null){
connectThread.cancel();
connectThread=null;
}
}
void bluetoothOn(){
if(bthAdapter == null){
Toast.makeText(getApplicationContext(),"블루투스를 지원하지 않는 기기입니다",Toast.LENGTH_SHORT).show();
}
else{
if(bthAdapter.isEnabled()){
Toast.makeText(getApplicationContext(),"블루투스가 이미 활성화된 상태입니다",Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(getApplicationContext(),"블루투스가 활성화 되어 있지 않습니다",Toast.LENGTH_SHORT).show();
Intent intentBthEnable = new Intent(bthAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(intentBthEnable,BT_REQUEST_ENABLE);
}
}
}
void bluetoothOff(){
if(bthAdapter.isEnabled()){
bthAdapter.disable();
Toast.makeText(getApplicationContext(),"블루투스가 비활성화 되었습니다.",Toast.LENGTH_SHORT).show();
bthStatus.setText("비활성화");
}
else{
Toast.makeText(getApplicationContext(),"블루투스가 이미 비활성화 상태입니다",Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onActivityResult(int requestCode,int resultCode,Intent data){
switch(requestCode){
case BT_REQUEST_ENABLE:
if(resultCode == RESULT_OK){
Toast.makeText(getApplicationContext(),"블루투스 활성화",Toast.LENGTH_LONG).show();
bthStatus.setText("활성화");
start();
} else if(resultCode == RESULT_CANCELED){
Toast.makeText(getApplicationContext(),"취소",Toast.LENGTH_LONG).show();
bthStatus.setText("비활성화");
}
break;
}
super.onActivityResult(requestCode,resultCode,data);
}
void listPairedDevices(){
if(bthAdapter.isEnabled()){
pairedDevices = bthAdapter.getBondedDevices();
if(pairedDevices.size()>0){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("장치 선택");
listofPairedDevices = new ArrayList();
for(BluetoothDevice device: pairedDevices){
listofPairedDevices.add(device.getName());
}
final CharSequence[] items= listofPairedDevices.toArray(new CharSequence[listofPairedDevices.size()]);
listofPairedDevices.toArray(new CharSequence[listofPairedDevices.size()]);
builder.setItems(items, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int item) {
connectSelectedDevice(items[item].toString());
}
});
AlertDialog alert=builder.create();
alert.show();
}
else{
Toast.makeText(getApplicationContext(),"페어링된 장치가 없습니다",Toast.LENGTH_LONG).show();
}
}
else{
Toast.makeText(getApplicationContext(),"블루투스가 비활성화 되어 있습니다.",Toast.LENGTH_LONG).show();
}
}
void connectSelectedDevice(String selectedDeviceName){
for(BluetoothDevice tempDevice: pairedDevices){
if(selectedDeviceName.equals(tempDevice.getName())){
bthDevice=tempDevice;
btAddress=bthDevice.getAddress();
break;
}
}
connect(bthDevice);
//Toast.makeText(getApplicationContext(),"연결 시도"+bthDevice.getName(),Toast.LENGTH_LONG).show();
}
public synchronized void start(){
acceptThread = new AcceptThread();
acceptThread.start();
}
public synchronized void connect(BluetoothDevice device){
connectThread=new ConnectThread(device);
connectThread.start();
}
private class AcceptThread extends Thread{
private final BluetoothServerSocket mmServerSocket;
public AcceptThread(){
BluetoothServerSocket tmp=null;
try{
tmp=bthAdapter.listenUsingRfcommWithServiceRecord("Listen",BT_UUID);
Toast.makeText(getApplicationContext(),"서버 열림",Toast.LENGTH_LONG).show();
}catch(IOException e){
Toast.makeText(getApplicationContext(),"서버 안열림",Toast.LENGTH_LONG).show();
}
mmServerSocket=tmp;
}
public void run(){
BluetoothSocket socket=null;
while(true){
try{
socket=mmServerSocket.accept();
} catch(IOException e){
break;
}
if(socket != null){
Toast.makeText(getApplicationContext(),"연결됨",Toast.LENGTH_SHORT).show();
try{
sleep(3000);
} catch (Exception e){}
}
}
}
public void cancel(){
try{
mmServerSocket.close();
} catch(IOException e){
e.printStackTrace();
}
}
}
private class ConnectThread extends Thread{
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device){
BluetoothSocket tmp=null;
mmDevice=device;
try{
tmp=device.createRfcommSocketToServiceRecord(BT_UUID);
//Toast.makeText(getApplicationContext(),"클라 초기화 됨.",Toast.LENGTH_LONG).show();
}catch (IOException e){
//Toast.makeText(getApplicationContext(),"클라 초기화 실패.",Toast.LENGTH_LONG).show();
}
mmSocket=tmp;
//Toast.makeText(getApplicationContext(),"클라 초기화",Toast.LENGTH_LONG).show();
}
public void run() {
try {
bthAdapter.cancelDiscovery();
mmSocket.connect();
Toast.makeText(getApplicationContext(), "클라이언트 연결", Toast.LENGTH_LONG).show();
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "연결실패", Toast.LENGTH_LONG).show();
}
}
public void cancel(){
try{
mmSocket.close();
} catch (IOException e){
e.printStackTrace();
}
}
}
}
'''
