Monitoring Battery Status in Your Flutter App with battery_plus

battery_plus is a Flutter plugin that provides access to the battery level and state for both Android and iOS platforms. With battery_plus, you can easily retrieve the current battery level and monitor changes in battery state.

To get started with using battery_plus in your Flutter project, follow these steps:

Step 1: Install the package

To install the battery_plus package, add the following dependency to your pubspec.yaml file:

dependencies: battery_plus: latest_version

After adding the dependency, run the command flutter pub get to download and install the package.

Step 2: Import the package

Once you have installed the package, you can import it in your Dart code by adding the following import statement:

import 'package:battery_plus/battery_plus.dart';

Step 3: Get battery level

To get the current battery level, you need to create an instance of the Battery class, which is provided by the battery_plus package. This class provides a method called batteryLevel that returns the current battery level as an integer between 0 and 100.

Here’s an example of how to use the Battery class to get the battery level:

Battery battery = Battery();
int batteryLevel = await battery.batteryLevel;
print('Battery level: $batteryLevel%');

In this example, we create an instance of the Battery class and call the batteryLevel method to get the current battery level. The await keyword is used to wait for the result, as the method is asynchronous.

Step 4: Monitor battery state

battery_plus also provides a way to monitor changes in battery state, such as changes in the charging status or the battery level. To do this, you need to create a Stream of battery state changes by calling the onBatteryStateChanged method on the Battery class.

Here’s an example of how to use the onBatteryStateChanged method to monitor changes in battery state:

Battery battery = Battery();
Stream<BatteryState> batteryState = battery.onBatteryStateChanged;
batteryState.listen((BatteryState state) {
  // Handle battery state change
  print('Battery state changed: $state');
});

In this example, we create a Stream of battery state changes by calling the onBatteryStateChanged method on the Battery class. We then listen to the stream and handle each battery state change as it occurs.

Note that the onBatteryStateChanged method returns a Stream of BatteryState objects, which represent the current state of the battery. The BatteryState enum provided by battery_plus includes values such as BatteryState.charging, BatteryState.full, and BatteryState.discharging.

Step 5: Check if device is charging

In addition to the battery level and state, battery_plus also provides a way to check if the device is currently charging. This can be done by calling the isCharging method on the Battery class.

Here’s an example of how to use the isCharging method to check if the device is charging:

Battery battery = Battery();
bool isCharging = await battery.isCharging;
print('Device is charging: $isCharging');

In this example, we create an instance of the Battery class and call the isCharging method to check if the device is currently charging. The await keyword is used to wait for the result, as the method is asynchronous.

Step 6: Handle errors

It’s important to handle any errors that may occur when using battery_plus, such as if the user denies permission to access the battery information. To handle errors, you can use a try-catch block when calling the relevant Battery methods.

Here’s an example of how to handle errors when getting the battery level:

Battery battery = Battery();
try {
  int batteryLevel = await battery.batteryLevel;
  print('Battery level: $batteryLevel%');
} catch (e) {
  print('Error getting battery level: $e');
}

In this example, we wrap the batteryLevel method call in a try-catch block. If an error occurs, we catch the error and print a message to the console.

Step 7: Permission handling for Android

On Android, the battery_plus plugin requires the android.permission.BATTERY_STATS permission to access battery information. To request this permission, you need to add the following line to your AndroidManifest.xml file:

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

Note that this permission is automatically added to your app when you add the battery_plus package to your project. However, you should still add this line to your AndroidManifest.xml file to ensure that the permission is properly requested at runtime.

Step 8: Permission handling for iOS

On iOS, the battery_plus plugin does not require any special permissions to access battery information.

Step 9: Support for desktop platforms

The battery_plus plugin supports desktop platforms such as Windows, macOS, and Linux. However, on these platforms, the plugin can only provide the battery level and state if the device has a built-in battery. If the device does not have a built-in battery, the plugin will return null.

Step 10: Limitations

Finally, it’s important to note that the battery_plus plugin may not work correctly on all devices or in all situations. For example, some devices may not report the battery level accurately, or the battery state may change unexpectedly. Additionally, the plugin may not work correctly in certain low-power modes or when the device is charging very slowly.

That being said, battery_plus is a reliable and easy-to-use plugin for accessing battery information in your Flutter app. By following the steps outlined above, you can easily retrieve the current battery level, monitor changes in battery state, and check if the device is charging.