一上午折腾，仍是一地鸡毛。andorid 蓝牙

 

package com.lingrui.btprint;

import android.app.AlertDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCallback;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    public static String MY_UUID="";
    /**
     * 代表本地蓝牙适配器（蓝牙无线电）。BluetoothAdapter是所有蓝牙交互的入口。
     * 使用这个你可以发现其他蓝牙设备，查询已配对的设备列表，
     * 使用一个已知的MAC地址来实例化一个BluetoothDevice，
     * 以及创建一个BluetoothServerSocket来为监听与其他设备的通信。
     */
    private BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    /**
     * 代表一个远程蓝牙设备，使用这个来请求一个与远程设备的BluetoothSocket连接，
     * 或者查询关于设备名称、地址、类和连接状态等设备信息。
     */
    private BluetoothDevice mBluetoothDevice = null;
    /**
     * 代表一个蓝牙socket的接口（和TCP Socket类似）。这是一个连接点，
     * 它允许一个应用与其他蓝牙设备通过InputStream和OutputStream交换数据。
     */
    private BluetoothSocket mBluetoothSocket = null;


    BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

    public ActivityResultLauncher<Intent> register;
    public void MyClick(View v){

    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_main);
        //点击蓝牙按钮
        Button btBlt = findViewById(R.id.bt_blt);
        btBlt.setOnClickListener(this);

        CheckBox ck_1= findViewById(R.id.ck_1);
     


        register = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), new ActivityResultCallback<ActivityResult>() {
            @Override
            public void onActivityResult(ActivityResult o) {
                int s = o.getResultCode();
                if (o == null) {
                    Log.e("error:", "打开失败");
                } else {
                    if (o.getResultCode() == RESULT_CANCELED) {
                        Log.d("debug", "用户取消");
                    }
                    if (o.getResultCode() == RESULT_OK) {
                        Log.d("debug", "蓝牙打开成功");
                    }
                }
            }
        });
    }
/*        BluetoothAdapter  bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        // 如果设备不支持蓝牙
        if (bluetoothAdapter == null)
        {
            Toast.makeText(getApplicationContext(), "该机型不支技蓝牙", Toast.LENGTH_SHORT).show();
            return;
        }
        // 设备支持蓝牙功能，启动蓝牙
        if (!bluetoothAdapter.isEnabled())
        {
            startBlueTooth.launch(new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE));
            Toast.makeText(getApplicationContext(), "开启蓝牙", Toast.LENGTH_SHORT).show();
        }*/


    @Override

    public void onClick(View v) {
        Toast.makeText(getApplicationContext(), "蓝牙TEST", Toast.LENGTH_SHORT).show();
        try {
            Log.d("debug", "点击打开蓝牙按钮");
            BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
            Log.d("debug", "22222222222");
            // 如果设备不支持蓝牙
            if (bluetoothAdapter == null) {
                Log.d("debug", "设备不支持蓝牙");
                return;
            }
            Log.d("debug", "3333333333");
            // 设备支持蓝牙功能，启动蓝牙
            if (!bluetoothAdapter.isEnabled()) {
                register.launch(new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE));
                Log.d("debug", "启动蓝牙");
            }
            Log.d("debug", "44444444444");
            //取得蓝牙开启状态
            //一旦蓝牙已经打开，我们可以使用蓝牙适配器来搜索附近的蓝牙设备
            String tmp = String.valueOf(PackageManager.PERMISSION_GRANTED);
            Log.d("debug", tmp);
            Log.d("debug", "5111111");
            tmp = String.valueOf(android.Manifest.permission.BLUETOOTH_CONNECT);
            Log.d("debug", tmp);
            tmp= String.valueOf((ActivityCompat.checkSelfPermission(this, android.Manifest.permission.BLUETOOTH_CONNECT)));
            Log.d("debug", tmp);
            if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.BLUETOOTH_CONNECT) != PackageManager.PERMISSION_GRANTED) {
                // TODO: Consider calling
                //    ActivityCompat#requestPermissions
                // here to request the missing permissions, and then overriding
                //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
                //                                          int[] grantResults)
                // to handle the case where the user grants the permission. See the documentation
                // for ActivityCompat#requestPermissions for more details.
                Log.d("debug", "5555555555555");
                return;
            }
            Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
            //getBondedDevices 方法返回已经配对的蓝牙设备的集合。通过遍历集合，可以获取设备的名称和地址等信息
            for (BluetoothDevice device : pairedDevices) {
                String deviceName = device.getName();
                String deviceAddress = device.getAddress();
                // 处理找到的设备信息
                Log.d("debug", deviceName);
                Log.d("debug", deviceAddress);
                mBluetoothDevice = device;
            }
            /*步骤四：连接蓝牙设备
            在搜索到蓝牙设备后，我们需要选择一个设备进行连接*/
            BluetoothSocket socket = mBluetoothDevice.createRfcommSocketToServiceRecord(UUID.fromString(MY_UUID));
            socket.connect();

            //连接成功后，我们可以通过蓝牙连接发送打印指令给蓝牙标签打印机。
            OutputStream outputStream = socket.getOutputStream();

        }catch (IllegalStateException | IOException e) {
            Log.d("debug", e.getMessage());
            Toast.makeText(getApplicationContext(), "蓝牙打开失败："+"\n"+e.getMessage(), Toast.LENGTH_SHORT).show();
        }




    }

    public void showPermissionDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this, android.R.style.Theme_DeviceDefault_Light_Dialog_NoActionBar_MinWidth);
        builder.setMessage("需要读SD卡权限，用来获取照片\n需要获取手机状态权限，用来获取设备号\n需要获取联系人权限，用来...");
        builder.setTitle("权限说明");
        builder.setCancelable(true);
        builder.setPositiveButton("申请", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                ;
            }
        });
        builder.show();
    }



}