1、MainActivity.java

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package club.stm32;
import android.Manifest;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
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.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    /**
     * 需要根据条件修改的参数
     */
    private String MacHeader = "A6:C0:80";  //蓝牙的Mac地址前六位，需要根据自己的蓝牙进行修改
    private BluetoothAdapter bluetoothAdapter;
    private Button btnCheckPermission;
    private TextView tvmsg;
    private Button btnSearchBLE;
    private BluetoothDevice mdevice;
    private BluetoothGatt bluetoothGatt;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getPermission();  //获取权限
        bluetoothInit();    //蓝牙初始化
        widgetInit();       //控件初始化
        widgetListener();   //控件监听
    }
    //获取权限
    private void getPermission() {
        //如果sdk版本大于23
        if (Build.VERSION.SDK_INT >=23){
            //如果没有权限
            if ((ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED))
            {
                //动态申请权限
                ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, 10);
            }
        }
    }
    //控件初始化
    private void widgetInit() {
        //请自行提升到全局，原型是：Button startscan = findViewById(R.id.startscan);
        btnCheckPermission = findViewById(R.id.btnCheckPermission);
        //请自行提升到全局，原型是：TextView tvmsg = findViewById(R.id.tvmsg);
        tvmsg = findViewById(R.id.tvmsg);
        //请自行提升到全局，原型是：Button btnSearchBLE = findViewById(R.id.btnSearchBLE);
        btnSearchBLE = findViewById(R.id.btnSearchBLE);
    }
    //控件监听
    private void widgetListener() {
        //测试权限按钮监听
        btnCheckPermission.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int permissionCheck = ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION);
                if (permissionCheck == PackageManager.PERMISSION_GRANTED) {//如果有权限
                    Toast.makeText(MainActivity.this, "hava this permission", Toast.LENGTH_SHORT).show();//toast信息
                    Log.d("权限：","有定位权限");//在logcat上打印信息
                    tvmsg.setText("有定位权限");
                }else {
                    getPermission();//获取权限
                    Toast.makeText(MainActivity.this, "no this permission", Toast.LENGTH_SHORT).show();//toast信息
                    Log.d("权限：","无定位权限");//在logcat上打印信息
                    tvmsg.setText("无定位权限");
                }
            }
        });
        //搜索蓝牙按钮监听
        btnSearchBLE.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //开始搜索蓝牙
                bluetoothAdapter.startLeScan(mBLEScanCallback);
            }
        });
    }
    //mBLEScanCallback回调函数
    private BluetoothAdapter.LeScanCallback mBLEScanCallback = new BluetoothAdapter.LeScanCallback() {
        @Override
        public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {
            //打印蓝牙mac地址
            Log.d("BleMAC", device.getAddress());
            if(device.toString().indexOf(MacHeader) == 0){
                Log.d("符合的蓝牙地址", device.getAddress());
                bluetoothAdapter.stopLeScan(mBLEScanCallback);
                //停止搜索蓝牙，降低功耗
                bluetoothAdapter.stopLeScan(mBLEScanCallback);
                //获取远程设备（连接蓝牙）原型是BluetoothDevice mdevice = bluetoothAdapter.getRemoteDevice(des);请自行提升全局
                mdevice = bluetoothAdapter.getRemoteDevice(device.toString());
                //连接bluetoothGatt 到这一步时，蓝牙已经连接上了
                //原型是BluetoothGatt bluetoothGatt = device.connectGatt(MainActivity.this, false, bluetoothGattCallback); 请自行提升全局
                //bluetoothGattCallback是蓝牙gatt回调函数，接下来会跳到bluetoothGattCallback函数
                bluetoothGatt = mdevice.connectGatt(MainActivity.this, false, bluetoothGattCallback);
                Log.d("已连接到蓝牙", device.getAddress());
            }
        }
    };
    //蓝牙回调函数
    private final BluetoothGattCallback bluetoothGattCallback = new BluetoothGattCallback() {
    };
    private void bluetoothInit() {
        //如果不支持蓝牙
        if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE))
        {
            //提示不支持蓝牙
            Toast.makeText(this, "程序不支持该设备", Toast.LENGTH_SHORT).show();
            //退出程序
            finish();
        }
        //创建蓝牙适配器原型是BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        //如果蓝牙适配器为空
        if (bluetoothAdapter == null)
        {
            //显示设备无蓝牙
            Toast.makeText(this, "设备无蓝牙", Toast.LENGTH_SHORT).show();
            //退出
            finish();
        }
        //如果蓝牙未开启
        if (!bluetoothAdapter.isEnabled())
        {
            //不提示,直接开启蓝牙
            bluetoothAdapter.enable();
            //提示开启蓝牙中
            Toast.makeText(this, "开启蓝牙中,如果未开启,请检查应用权限", Toast.LENGTH_SHORT).show();
        }
    }
}

2、布局文件activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:text="Hello World!"
        android:id="@+id/tvmsg"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="测试权限"
            android:id="@+id/btnCheckPermission"
            />
        <Button
            android:layout_weight="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="搜索蓝牙"
            android:id="@+id/btnSearchBLE"
            />
    </LinearLayout>
</LinearLayout>