android studio判断是否连接wifi的代码

以下是一个简单的Android Studio代码示例，用于检查设备是否连接到WiFi网络：

public boolean isWifiConnected() {
    ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
        return true;
    } else {
        return false;
    }
}

在上面的示例中，我们使用ConnectivityManager类来获取当前网络连接的信息。如果设备当前连接到WiFi网络，则返回true，否则返回false。

相关问题

android studio实现串口通信

要在Android Studio中实现串口通信，您需要遵循以下步骤：

1. 配置权限：在AndroidManifest.xml文件中添加以下行：

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
<uses-permission android:name="android.permission.READ_LOGS" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.NFC" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.WRITE_CONTACTS" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.READ_PROFILE" />
<uses-permission android:name="android.permission.WRITE_PROFILE" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />
<uses-permission android:name="android.permission.ACCESS_NOTIFICATION_POLICY" />
<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
<uses-permission android:name="android.permission.INSTALL_PACKAGES" />
<uses-permission android:name="android.permission.DOWNLOAD_WITHOUT_NOTIFICATION" />
<uses-permission android:name="android.permission.REQUEST_DELETE_PACKAGES" />
<uses-permission android:name="android.permission.DELETE_PACKAGES" />
<uses-permission android:name="android.permission.ANSWER_PHONE_CALLS" />
<uses-permission android:name="android.permission.READ_PHONE_NUMBERS" />
<uses-permission android:name="android.permission.ANSWER_PHONE_CALLS" />
<uses-permission android:name="android.permission.READ_PHONE_NUMBERS" />
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
<uses-permission android:name="android.permission.ACTIVITY_RECOGNITION" />
<uses-permission android:name="android.permission.BODY_SENSORS" />
<uses-permission android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
<uses-permission android:name="android.hardware.usb.action.USB_DEVICE_DETACHED" />
<uses-feature android:name="android.hardware.usb.host" />

2. 添加依赖项：在build.gradle文件中添加以下依赖项：

dependencies {
    implementation 'com.android.support:support-v4:28.0.0'
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:design:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation files('libs/usbSerialForAndroid.jar')
}

3. 添加代码：在您的Android Studio项目中添加以下代码：

public class MainActivity extends AppCompatActivity implements UsbSerialInterface.UsbReadCallback {

    private static final String TAG = MainActivity.class.getSimpleName();
    private UsbManager usbManager;
    private UsbDevice device;
    private UsbSerialDevice serialPort;
    private UsbDeviceConnection connection;
    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = findViewById(R.id.text_view);

        usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
        IntentFilter filter = new IntentFilter();
        filter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
        filter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
        registerReceiver(usbReceiver, filter);

        //获取设备列表
        HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();
        if (!deviceList.isEmpty()) {
            boolean keep = true;
            for (UsbDevice device : deviceList.values()) {
                // 判断设备VID和PID是否符合
                if (device.getVendorId() == 0x1a86 && device.getProductId() == 0x7523) {
                    // 找到设备
                    this.device = device;
                    Log.i(TAG, "找到设备");
                    break;
                } else {
                    connection = null;
                    this.device = null;
                }
            }
            if (device == null) {
                Log.e(TAG, "没有找到设备");
                return;
            }
        } else {
            Log.e(TAG, "没有设备");
            return;
        }
        // 打开设备，获取 UsbDeviceConnection 对象，连接设备，用于后面的通讯
        connection = usbManager.openDevice(device);
        if (connection == null) {
            Log.e(TAG, "连接失败");
            return;
        }
        serialPort = UsbSerialDevice.createUsbSerialDevice(device, connection);
        if (serialPort != null) {
            if (serialPort.open()) { // 开启设备
                //设置波特率
                serialPort.setBaudRate(9600);
                //设置数据位
                serialPort.setDataBits(UsbSerialInterface.DATA_BITS_8);
                //设置停止位
                serialPort.setStopBits(UsbSerialInterface.STOP_BITS_1);
                //设置校验位
                serialPort.setParity(UsbSerialInterface.PARITY_NONE);
                //设置流控制
                serialPort.setFlowControl(UsbSerialInterface.FLOW_CONTROL_OFF);

                // 开启读取线程，开始接收数据
                serialPort.read(this);
                Log.i(TAG, "连接成功");
            } else {
                serialPort.close();
                Log.e(TAG, "开启设备失败");
            }
        } else {
            Log.e(TAG, "没有找到设备");
        }
    }

    @Override
    public void onReceivedData(byte[] bytes) {
        // 接收到数据的回调
        runOnUiThread(() -> {
            String s = new String(bytes);
            textView.setText(s);
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(usbReceiver);
        if (serialPort != null) {
            serialPort.close();
        }
    }

    private BroadcastReceiver usbReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
                // USB设备插入
                Log.i(TAG, "USB设备已插入");
            } else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
                // USB设备拔出
                Log.i(TAG, "USB设备已拔出");
            }
        }
    };
}

在这个示例中，我们使用了USB to TTL串口模块。请注意，您需要正确设置波特率、数据位、停止位、校验位和流控制，以便与您的设备通信。

希望这个步骤能够帮助您在Android Studio中实现串口通信。