如何在iOS中获取电池使用情况和设备的电量

Question

I want to get battery usage data from my iPhone. I used UIDevice currentDevice.batteryLevel code, but its returning -1.0000 in NSLog value.

Anyone please help me?

One more question, can I able to fetch other app battery usages in my app?

Answer 1

First, you must enable batteryStatus notification (in appDelegate.m for instance):

- (void)applicationDidBecomeActive:(UIApplication *)application {
    ...
    [[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];
    // Now, the system will post UIDeviceBatteryStateDidChangeNotification notification when batteryStatus (or connection) will change

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(batteryStatusDidChange:) name:UIDeviceBatteryStateDidChangeNotification object:nil];
    ...
}

Then, you can check battery level calling:

[UIDevice currentDevice].batteryLevel;

that will return you a value between 0.0 (0% chareg) and 1.0 (100% charge).

Without calling first setBatteryMonitoringEnabled , battery state will return UIDeviceBatteryStateUnknown and the value of this property is –1.0. (from docs).