//佈局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
tools:context="com.a1511j.day02_.MainActivity"
 
>

    <Button
android:id="@+id/btn_start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="開啟藍芽"
tools:layout_editor_absoluteX="6dp"
tools:layout_editor_absoluteY="3dp"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart=
 
"true"
android:layout_marginLeft="120dp"
android:layout_marginStart="120dp"
android:layout_marginTop="40dp" />

    <Button
android:id="@+id/btn_stop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="關閉藍芽"
tools:layout_editor_absoluteX="-3dp"
tools:layout_editor_absoluteY=
 
"77dp"
android:layout_below="@+id/btn_start"
android:layout_alignLeft="@+id/btn_start"
android:layout_alignStart="@+id/btn_start"
android:layout_marginTop="58dp" />

    <Button
android:id="@+id/btn_discoverable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="可被發現藍芽"
tools:layout_editor_absoluteX="-3dp"
tools:layout_editor_absoluteY="155dp"
android:layout_below="@+id/btn_stop"
android:layout_alignLeft="@+id/btn_stop"
android:layout_alignStart="@+id/btn_stop"
android:layout_marginTop="51dp" />

    <Button
android:id="@+id/btn_search"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="搜尋藍芽"
tools:layout_editor_absoluteX="6dp"
tools:layout_editor_absoluteY="250dp"
android:layout_marginLeft="17dp"
android:layout_marginStart="17dp"
android:layout_alignParentBottom="true"
android:layout_alignLeft="@+id/btn_stop"
android:layout_alignStart="@+id/btn_stop"
android:layout_marginBottom="106dp" />

</RelativeLayout>

mian

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class MainActivity extends AppCompatActivity {

    //代替findviewByid;
@BindView(R.id.btn_start)
    Button btnStart;
    @BindView(R.id.btn_stop)
    Button btnStop;
    @BindView(R.id.btn_discoverable)
    Button btnSearch;
    @BindView(R.id.btn_search)
    Button button4;
    private BluetoothAdapter bluetoothAdapter;
    @Override
protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        //獲取藍芽介面卡
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    }

    @OnClick({R.id.btn_start, R.id.btn_stop, R.id.btn_search, R.id.btn_discoverable})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.btn_start:
                bluetoothAdapter.enable();
                Toast.makeText(MainActivity.this,"藍芽已開啟",Toast.LENGTH_SHORT).show();
                break;
            case R.id.btn_stop:
                bluetoothAdapter.disable();
                Toast.makeText(MainActivity.this,"藍芽已關閉",Toast.LENGTH_SHORT).show();
                break;
            case R.id.btn_discoverable:
                discoverableBluetooth();

                break;
            case R.id.btn_search:
                searchBluetooh();
                break;
        }
    }


    /**
     * 開啟藍芽的可檢測性
     */
private void discoverableBluetooth() {

        Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
        startActivityForResult(intent,0);
        Toast.makeText(MainActivity.this,"藍芽可檢測性已開啟",Toast.LENGTH_SHORT).show();
    }

    //搜尋藍芽
private void searchBluetooh() {
        //新增藍芽可以被發現
IntentFilter intentFilter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        MBluetoothBroadCast mBluetoothBroadCast = new MBluetoothBroadCast();
        registerReceiver(mBluetoothBroadCast,intentFilter);

        IntentFilter intentFilter1 = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        registerReceiver(mBluetoothBroadCast,intentFilter1);

        //開始找藍芽裝置
bluetoothAdapter.startDiscovery();


    }

    //符合我註冊的過濾器 ,就可以進入onReceive方法
class MBluetoothBroadCast extends BroadcastReceiver {
        //一旦被發現或連結,我們就能能收到廣播;
@Override
public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            //如果我們搜尋到了其他的藍芽,就會進入這個判斷
if( BluetoothDevice.ACTION_FOUND.equals(action)){
                //得到搜尋到的藍芽裝置
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

                if(device.getBondState()!=BluetoothDevice.BOND_BONDED){
                    //用裝置獲取藍芽名字
System.out.println(device.getName()+",,,,,,,,,,,,,,,,");
                }
                //如果搜尋完畢,會進入這個判斷;
}else if(BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)){
                Toast.makeText(MainActivity.this, "已搜數完成", Toast.LENGTH_LONG).show();

            }

        }
    }


    @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

    }
}

//開啟藍芽的依賴

compile 'com.jakewharton:butterknife:8.8.1'
annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'

//開啟藍芽的許可權

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />