React Native Get battery status / level Using Native Modules

Question

I am writing a react native app to get IOS and Android Battery status. I search through the net and found few libraries which can get battery level of the phone.

https://github.com/robinpowered/react-native-device-battery

https://github.com/remobile/react-native-battery-status

https://github.com/oojr/react-native-battery

Every library has issues when I try that and not much support for the developer when ask a question on git hub.

Can any one provide me better solution or library to get Battery status of IOS and Android.

Thanks in advance

Hynes

Hi, I have the same situation right now. Have you solved it and found a working solution? Thanks for your help. – Manslayer

@StefanN. I posted an answer to my question – Hynes

Ah got it, must have missed that ^^. Actually it looks like your answer gonna help me to find out how to connect native code with the react part and how to get the battery level. Thank you. – Manslayer

Answer 1

I wrote my own IOS and Android classes to get the Battery Status. Here are the steps if any one interested on that,

For IOS,

1. Open the iOS project in XCode
2. Create 2 new files call BatteryStatus.h and BatteryStatus.m

BatteryStatus.h file should contain following code

#import <Foundation/Foundation.h>
#import <React/RCTBridgeModule.h>
#import <React/RCTEventEmitter.h>

@interface BatteryStatus : RCTEventEmitter <RCTBridgeModule>
@end

BatteryStatus.m file should

#import "BatteryStatus.h"

@implementation BatteryStatus
RCT_EXPORT_MODULE(BatteryStatus)

- (instancetype)init
{
 if ((self = [super init])) {

   [[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];

 }
 return self;
}

RCT_EXPORT_METHOD(hide) {
}

RCT_EXPORT_METHOD(updateBatteryLevel:(RCTResponseSenderBlock)callback)
{
 callback(@[[self getBatteryStatus]]);
}

 //manually get battery status by calling following method

-(NSDictionary*)getBatteryStatus
{

 float batteryLevel = [UIDevice currentDevice].batteryLevel;

 NSObject* currentLevel = nil;

 currentLevel = [NSNumber numberWithFloat:(batteryLevel * 100)];

 NSMutableDictionary* batteryData = [NSMutableDictionary dictionaryWithCapacity:2];

 [batteryData setObject:currentLevel forKey:@"level"];
 return batteryData;

  }

@end

3. Inside your react native app, inside your js file add following code

   import { NativeModules } from 'react-native';
   
   constructor(props) {
    super(props);
    this.state = {
    batteryLevel: null,
    };
   }
   
   componentDidMount() {
     NativeModules.BatteryStatus.updateBatteryLevel((info) => {
     //console.log(info.level)
     const level = Math.ceil(info.level);
     this.setState({ batteryLevel: level});
     });
   }
   

For IOS above code is working for me to get the battery level

For Android,

1. Open the Android project in Android Studio
2. Create a group call BatteryStatus and include 2 Files named , BatteryStatusModule.java and BatteryStatusPackage.java

BatteryStatusModule.java Should contain following code

package com.yourproject.BatteryStatus;

import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;

import com.facebook.react.bridge.Callback;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.ReactMethod;

public class BatteryStatusModule extends ReactContextBaseJavaModule  {
     public BatteryStatusModule(ReactApplicationContext reactContext) {

         super(reactContext);
     }

     @Override
     public String getName() {
    return "BatteryStatus";
}

@ReactMethod
public void getBatteryStatus(Callback successCallback) {
    Intent batteryIntent = getCurrentActivity().registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
    int level = batteryIntent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
    int scale = batteryIntent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);

    if(level == -1 || scale == -1) {
        level = 0;
    }
    //System.out.print("battery level");
    //System.out.print(level);
    successCallback.invoke(null ,((float)level / (float)scale) * 100.0f);
    }
 }

BatteryStatusPackage.java should contain following code

 package com.yourproject.BatteryStatus;

 import com.facebook.react.ReactPackage;
 import com.facebook.react.bridge.JavaScriptModule;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.uimanager.ViewManager;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;

 public class BatteryStatusPackage implements ReactPackage {
@Override
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
    List<NativeModule> modules = new ArrayList<>();

    modules.add(new BatteryStatusModule(reactContext));

    return modules;
}

@Override
public List<Class<? extends JavaScriptModule>> createJSModules() {
    return Collections.emptyList();
}

@Override
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
    return Collections.emptyList();
}
}

4. Inside MainApplication.java include following code

   @Override
   protected List<ReactPackage> getPackages() {
     return Arrays.<ReactPackage>asList(
         new MainReactPackage(),
           new MapsPackage(),
           new BatteryStatusPackage()
     );
   }
   

5. Inside your react native app, inside your js file add following code

    import { NativeModules } from 'react-native';
   
    constructor(props) {
    super(props);
   
    this.state = {
      batteryLevel: null
    };
   }
   
   getBatteryLevel = (callback) => {
      NativeModules.BatteryStatus.getBatteryStatus(callback);
   }
   

6.Call it something like this:

componentDidMount() {
 this.getBatteryLevel((batteryLevel) => {
   console.log(batteryLevel);
 });
}

For Android above code is working for me to get the battery level

Hope this will help some one to get battery level for IOS and ANDROID

Hynes

Answer 2

We can use react-native-device-info for getting any device's specific information.

Install with command

npm install --save react-native-device-info
# or
yarn add react-native-device-info

Get the battery level of the device as a float comprised between 0 and 1 with getBatteryLevel().

DeviceInfo.getBatteryLevel().then(batteryLevel => {
    console.log(batteryLevel);
    // 0.759999
});

Note:

Returns -1 on the iOS Simulator

Freddafreddi

Answer 3

Just some addition to the right answer. You have to override the 'supportedEvents' function in the BatteryStatus.m file to make it work like this :

-(NSArray<NSString *> *)supportedEvents{ 
  return @[@"level"];
}

Disquisition