Android 判断蓝牙是否开启，监听蓝牙状态，处理客制化需求

import android.bluetooth.BluetoothAdapter;

【BluetoothAdapter.java】

@SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)

public static final String
ACTION_STATE_CHANGED = "android.bluetooth.adapter.action.STATE_CHANGED";//当前action动作

/**
* Used as an int extra field in {@link #ACTION_STATE_CHANGED}
* intents to request the current power state. Possible values are:
* {@link #STATE_OFF},
* {@link #STATE_TURNING_ON},
* {@link #STATE_ON},
* {@link #STATE_TURNING_OFF},
*/

//intent.getIntExtra 参数
public static final String EXTRA_STATE = "android.bluetooth.adapter.extra.STATE";//当前状态

public static final String EXTRA_PREVIOUS_STATE =
"android.bluetooth.adapter.extra.PREVIOUS_STATE";//上一个状态

public static final int STATE_OFF = 10;

public static final int STATE_TURNING_ON = 11;

public static final int STATE_ON = 12;

public static final int STATE_TURNING_OFF = 13;

BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
boolean bluetoothEnable = bluetoothAdapter == null ? false : bluetoothAdapter.isEnabled();
if (bluetoothEnable) {//判断蓝牙是否开启
//处理逻辑
}

监听蓝牙广播：

IntentFilter bt = new IntentFilter();
bt.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
mContext.registerReceiver(mReceiver, bt);

private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);//监听当前蓝牙状态

switch (state) {
case BluetoothAdapter.STATE_OFF:
//添加其他处理逻辑，比如亮灭led灯，密码弹窗，控制可用禁用等
break;
case BluetoothAdapter.STATE_ON:
//添加其他处理逻辑
break;

case BluetoothAdapter.STATE_TURNING_OFF:
break;

case BluetoothAdapter.STATE_TURNING_ON:
break;
}
}
}
};