# WiFi Keep-Alive Feature

## Overview

This document describes the implementation of the WiFi keep-alive feature in the robot application. The feature prevents frequent WiFi disconnections by using Android's WifiLock mechanism to keep the WiFi radio awake even when the device is idle.

## Implementation Details

### WiFiKeepAliveManager

The core component of this feature is the [WiFiKeepAliveManager](file:///d:/ismart_peng/source/robot/app/app/src/main/java/com/ismart/ib86/feature/network/WiFiKeepAliveManager.java#L12-L101) class, which manages the WifiLock lifecycle:

1. **Initialization**: Acquires WifiManager and creates WifiLock
2. **Network Monitoring**: Listens to network state changes using [NetworkStateMonitor](file:///d:/ismart_peng/source/robot/app/app/src/main/java/com/ismart/ib86/feature/network/NetworkStateMonitor.java#L15-L149)
3. **WifiLock Management**: Acquires lock when WiFi is connected, releases when disconnected
4. **Resource Cleanup**: Properly releases resources when destroyed

### Integration

The [WiFiKeepAliveManager](file:///d:/ismart_peng/source/robot/app/app/src/main/java/com/ismart/ib86/feature/network/WiFiKeepAliveManager.java#L12-L101) is integrated into the [MainActivity](file:///d:/ismart_peng/source/robot/app/app/src/main/java/com/ismart/ib86/app/MainActivity.java#L74-L1315) and is initialized during the application startup. It's destroyed when the application is terminated.

### Permissions

The following permissions were added to [AndroidManifest.xml](file:///d:/ismart_peng/source/robot/app/app/src/main/AndroidManifest.xml):

```xml
<uses-permission android:name="android.permission.WAKE_LOCK" />
```

The following permissions were already present:
```xml
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
```

## Key Components

### WiFiKeepAliveManager.java

Located at: `app/src/main/java/com/ismart/ib86/feature/network/WiFiKeepAliveManager.java`

Main methods:
- `initialize()`: Sets up network state monitoring
- `acquireWifiLock()`: Acquires the WiFi lock when WiFi is connected
- `releaseWifiLock()`: Releases the WiFi lock when WiFi is disconnected
- `destroy()`: Cleans up resources

### Integration in MainActivity.java

The [WiFiKeepAliveManager](file:///d:/ismart_peng/source/robot/app/app/src/main/java/com/ismart/ib86/feature/network/WiFiKeepAliveManager.java#L12-L101) is initialized in the [initNetworkStateManager()](file:///d:/ismart_peng/source/robot/app/app/src/main/java/com/ismart/ib86/app/MainActivity.java#L484-L492) method and destroyed in the `onDestroy()` method of [MainActivity](file:///d:/ismart_peng/source/robot/app/app/src/main/java/com/ismart/ib86/app/MainActivity.java#L74-L1315).

## Testing

A unit test class [WiFiKeepAliveManagerTest.java](file:///d:/ismart_peng/source/robot/app/app/src/test/java/com/ismart/ib86/feature/network/WiFiKeepAliveManagerTest.java) has been created to test the functionality:

- Test creation of the manager
- Test acquiring WiFi lock
- Test releasing WiFi lock
- Test destroying the manager

Located at: `app/src/test/java/com/ismart/ib86/feature/network/WiFiKeepAliveManagerTest.java`

## Benefits

1. **Stable WiFi Connection**: Prevents frequent WiFi disconnections
2. **Continuous Network Communication**: Ensures stable network connectivity for robot functionalities
3. **Automatic Management**: Automatically acquires and releases WiFi lock based on network state
4. **Resource Efficient**: Only holds WiFi lock when WiFi is connected

## Performance Considerations

1. **Battery Impact**: Using WifiLock will increase battery consumption as WiFi radio remains active
2. **Optimization**: Only acquire WifiLock when WiFi is connected, release when disconnected
3. **Android Version Compatibility**: Handles differences in WiFi management across Android versions

## Error Handling

The implementation includes proper error handling:
- Handles cases where WifiLock cannot be acquired
- Gracefully handles missing permissions
- Logs errors for debugging and monitoring