Get battery level and state in Android

问题

How can I get battery level and state (plugged in, discharging, charging, etc)? I researched the developer docs and I found a BatteryManager class. But it doesn\'t contain any methods, just constants. How do I even use it?

回答1:

Here is a code sample that explains how to get battery information.

To sum it up, a broadcast receiver for the ACTION_BATTERY_CHANGED intent is set up dynamically, because it can not be received through components declared in manifests, only by explicitly registering for it with Context.registerReceiver().

public class Main extends Activity {
  private TextView batteryTxt;
  private BroadcastReceiver mBatInfoReceiver = new BroadcastReceiver(){
    @Override
    public void onReceive(Context ctxt, Intent intent) {
      int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
      batteryTxt.setText(String.valueOf(level) + "%");
    }
  };

  @Override
  public void onCreate(Bundle b) {
    super.onCreate(b);
    setContentView(R.layout.main);
    batteryTxt = (TextView) this.findViewById(R.id.batteryTxt);
    this.registerReceiver(this.mBatInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
  }
}

回答2:

Since API 21 its been possible to use the following to get current battery level as a percentage:

BatteryManager bm = (BatteryManager)getSystemService(BATTERY_SERVICE);
int batLevel = bm.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY);

回答3:

Based on official android docs, you can use this method in a Helper or Util class to get current battery percentage:

public static int getBatteryPercentage(Context context) {

    if (Build.VERSION.SDK_INT >= 21) {

         BatteryManager bm = (BatteryManager) context.getSystemService(BATTERY_SERVICE);
         return bm.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY);

    } else {

         IntentFilter iFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
         Intent batteryStatus = context.registerReceiver(null, iFilter);

         int level = batteryStatus != null ? batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1) : -1;
         int scale = batteryStatus != null ? batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1) : -1;

         double batteryPct = level / (double) scale;

         return (int) (batteryPct * 100);
   }
}

回答4:

You don't have to register an actual BroadcastReceiver as Android's BatteryManager is using a sticky Intent:

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
Intent batteryStatus = registerReceiver(null, ifilter);

int level = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
int scale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1);

float batteryPct = level / (float)scale;

return (int)(batteryPct*100);

This is from the official docs over at https://developer.android.com/training/monitoring-device-state/battery-monitoring.html.

回答5:

You can use this to get remaining charged in percentage.

private void batteryLevel() {
        BroadcastReceiver batteryLevelReceiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                context.unregisterReceiver(this);
                int rawlevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
                int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
                int level = -1;
                if (rawlevel >= 0 && scale > 0) {
                    level = (rawlevel * 100) / scale;
                }
                batterLevel.setText("Battery Level Remaining: " + level + "%");
            }
        };
        IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        registerReceiver(batteryLevelReceiver, batteryLevelFilter);
    }

回答6:

try this function no need permisson or any reciver

void getBattery_percentage()
{
      IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
      Intent batteryStatus = getApplicationContext().registerReceiver(null, ifilter);
      int level = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
      int scale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
      float batteryPct = level / (float)scale;
      float p = batteryPct * 100;

      Log.d("Battery percentage",String.valueOf(Math.round(p)));
  }

回答7:

To check battery percentage we use BatteryManager, the following method will return battery percentage.

Source Link

public static float getBatteryLevel(Context context, Intent intent) {
    Intent batteryStatus = context.registerReceiver(null,
            new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
    int batteryLevel = -1;
    int batteryScale = 1;
    if (batteryStatus != null) {
        batteryLevel = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, batteryLevel);
        batteryScale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, batteryScale);
    }
    return batteryLevel / (float) batteryScale * 100;
}

回答8:

private void batteryLevel() {
        BroadcastReceiver batteryLevelReceiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                context.unregisterReceiver(this);
                int rawlevel = intent.getIntExtra("level", -1);
                int scale = intent.getIntExtra("scale", -1);
                int level = -1;
                if (rawlevel >= 0 && scale > 0) {
                    level = (rawlevel * 100) / scale;
                }
                mBtn.setText("Battery Level Remaining: " + level + "%");
            }
        };
        IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        registerReceiver(batteryLevelReceiver, batteryLevelFilter);
    }

回答9:

one mistake in official docs, you must use double instead float. Because 0.53F * 100F = 52F

int level = batteryStatus != null ? 
batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1) : -1; int scale = 
batteryStatus != null ? batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1) : -1; 
double batteryPct = (double) level / (double) scale; int percent = (int) (batteryPct * 100D);

回答10:

After some MORE researching, I found BatteryManager.EXTRA_LEVEL.

回答11:

Other answers didn't mention how to access battery status (chraging or not).

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
Intent batteryStatus = context.registerReceiver(null, ifilter);

// Are we charging / charged?
int status = batteryStatus.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
                     status == BatteryManager.BATTERY_STATUS_FULL;

// How are we charging?
int chargePlug = batteryStatus.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB;
boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC;

来源：https://stackoverflow.com/questions/3291655/get-battery-level-and-state-in-android

标签

java

android

battery