[Android] BatteryManager バッテリー情報を取り出す

バッテリーの充電情報を BatteryManager と Broadcast Intent のACTION_BATTERY_CHANGED を使って取得できます。また、Lollipop で追加された機能もあります。
　

Android Studio
２０21.2.1

BateryManager

BatteryManagerはバッテリー情報を sticky Intent でブロードキャストしますが、sticky Intent なので BroadCast の登録をわざわざしなくてもよく、null を渡せばできます。
Ref: BatteryManager
Monitoring the Battery Level and Charging State
　
簡単に今の電池残量は下のようにして取得できます
　

//package your.package.name;

import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

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

        int batteryLevel = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
        Log.d("Battery","Level: " + batteryLevel);
    }
}

//package your.package.name;

import android.content.Intent;

import android.content.IntentFilter;

import android.os.BatteryManager;

import android.os.Bundle;

import android.util.Log;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

IntentFilter intentfilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);

Intent batteryStatus = this.registerReceiver(null, intentfilter );

int batteryLevel = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);

Log.d("Battery","Level: " + batteryLevel);

}

　
バッテリーレベルはログによると「91」です

2022-06-09 13:00:04.527 10393-10393/com.example.testbatterylevel D/Battery: Level: 91

1	2022-06-09 13:00:04.527 10393-10393/com.example.testbatterylevel D/Battery: Level: 91

ただ、正確には BatteryManager.EXTRA_SCALE で最大値を出して
level/maxLevel
のように計算しますが、大概Max は100の場合が多いようですのでそのまま％で扱えます。

MainActivity.java

//package your.package.name;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private final StringBuilder sbuilder = new StringBuilder();
    private Intent batteryStatus;
    private BatteryManager bManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);

        batteryStatus = this.registerReceiver(null, ifilter);

        if(batteryStatus != null) {
            baInfo();
        }

        // 以降は Lollipop と機種によるサポートの違いあり
        bManager = (BatteryManager)this.getSystemService(Context.BATTERY_SERVICE);

        if(bManager != null){
            batteryAgeing();
        }

        TextView textView = findViewById(R.id.text_view);
        textView.setText(sbuilder);

    }

    private void baInfo(){

        // Battery Level
        int level = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_LEVEL, -1);
        sbuilder.append("Level: ");
        sbuilder.append(level);
        sbuilder.append("\n");

        // Battery Health
        int bh = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_HEALTH, -1);
        sbuilder.append("Health: ");
        sbuilder.append(batteryHealth(bh));
        sbuilder.append("\n");

        // icon ID
        int bi = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_ICON_SMALL, -1);
        sbuilder.append("Icon: ");
        sbuilder.append(bi);
        sbuilder.append("\n");

        // Battery plugged
        int bpl = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_PLUGGED, -1);
        sbuilder.append("Plugged: ");
        sbuilder.append(batteryPluggCheck(bpl));
        sbuilder.append("\n");

        // Battery present or not
        boolean bpr = batteryStatus.getBooleanExtra(
                BatteryManager.EXTRA_PRESENT, false);
        sbuilder.append("Present: ");
        sbuilder.append(batteryPresent(bpr));
        sbuilder.append("\n");

        // scale
        int bsc = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_SCALE, -1);
        sbuilder.append("Scale: ");
        sbuilder.append(bsc);
        sbuilder.append("\n");

        // Battery status
        int bst = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_STATUS, -1);
        sbuilder.append("Status: ");
        sbuilder.append(status(bst));
        sbuilder.append("\n");

        // Battery technology
        String bte = batteryStatus.getStringExtra(
                BatteryManager.EXTRA_TECHNOLOGY);
        sbuilder.append("Technology: ");
        sbuilder.append(bte);
        sbuilder.append("\n");

        // temperature
        int btp = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_TEMPERATURE, -1);
        sbuilder.append("Tempareture: ");
        sbuilder.append((float)btp/10);
        sbuilder.append(" ℃\n");

        // Voltage
        int bv = batteryStatus.getIntExtra(
                BatteryManager.EXTRA_VOLTAGE, -1);
        sbuilder.append("Voltage: ");
        sbuilder.append((float)bv/1000);
        sbuilder.append(" [v]\n\n");

    }

    private String batteryHealth(int bh){
        String health = null;

        if(bh == BatteryManager.BATTERY_HEALTH_GOOD){
            health = "GOOD";
        }
        else if(bh == BatteryManager.BATTERY_HEALTH_DEAD){
            health = "DEAD";
        }
        else if(bh == BatteryManager.BATTERY_HEALTH_COLD){
            health = "COLD";
        }
        else if(bh == BatteryManager.BATTERY_HEALTH_OVERHEAT){
            health = "OVERHEAT";
        }
        else if(bh == BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE){
            health = "OVER_VOLTAGE";
        }
        else if(bh == BatteryManager.BATTERY_HEALTH_UNKNOWN){
            health = "UNKNOWN";
        }
        else if(bh == BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE){
            health = "UNSPECIFIED_FAILURE";
        }

        return health;
    }

    private String batteryPluggCheck(int bpl){
        String plugged = "NOT PLUGGED";
        if(bpl == BatteryManager.BATTERY_PLUGGED_AC){
            plugged = "PLUGGED AC";
        }
        else if(bpl == BatteryManager.BATTERY_PLUGGED_USB){
            plugged = "PLUGGED USB";
        }
        else if(bpl == BatteryManager.BATTERY_PLUGGED_WIRELESS){
            plugged = "PLUGGED WIRELESS";
        }

        return plugged;
    }

    private String batteryPresent(boolean bpr){
        String present;
        if(bpr){
            present = "PRESENT";
        }
        else{
            present = "NOT PRESENT";
        }
        return present;
    }

    private String status(int bst){
        String status = "?";
        if(bst == BatteryManager.BATTERY_STATUS_CHARGING){
            status = "CHARGING";
        }
        else if(bst == BatteryManager.BATTERY_STATUS_DISCHARGING){
            status = "DISCHARGING";
        }
        else if(bst == BatteryManager.BATTERY_STATUS_FULL){
            status = "FULL";
        }
        else if(bst == BatteryManager.BATTERY_STATUS_NOT_CHARGING){
            status = "NOT CHARGING";
        }
        else if(bst == BatteryManager.BATTERY_STATUS_UNKNOWN){
            status = "UNKNOWN";
        }

        return status;
    }

    private void batteryAgeing(){
        // RemainingCapacityRatio
        int remainingCapacityRatio = bManager.getIntProperty(
                BatteryManager.BATTERY_PROPERTY_CAPACITY);
        sbuilder.append("RemainingCapacityRatio: ");
        sbuilder.append(remainingCapacityRatio);
        sbuilder.append(" %\n");

        // BatteryCapacityMicroAh
        int batteryCapacityMicroAh = bManager.getIntProperty(
                BatteryManager.BATTERY_PROPERTY_CHARGE_COUNTER);
        sbuilder.append("BatteryCapacityMicroAh: ");
        sbuilder.append(batteryCapacityMicroAh);
        sbuilder.append(" uAh\n");

        // DischargingTimeSeconds
        int dischargingTimeSeconds  = bManager.getIntProperty(
                BatteryManager.BATTERY_PROPERTY_CURRENT_AVERAGE);
        sbuilder.append("DischargingTimeSeconds: ");
        sbuilder.append(dischargingTimeSeconds);
        sbuilder.append(" msec\n");

        // Current
        int currentNow  = bManager.getIntProperty(
                BatteryManager.BATTERY_PROPERTY_CURRENT_NOW);
        sbuilder.append("CurrentNow: ");
        sbuilder.append(currentNow);
        sbuilder.append(" uA\n");

        // EnergyCounter
        long energyCounter  = bManager.getLongProperty(
                BatteryManager.BATTERY_PROPERTY_ENERGY_COUNTER);
        sbuilder.append("EnergyCounter: ");
        sbuilder.append(energyCounter);
        sbuilder.append(" nWh\n\n");

    }
}

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//package your.package.name;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.os.BatteryManager;

import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private final StringBuilder sbuilder = new StringBuilder();

private Intent batteryStatus;

private BatteryManager bManager;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);

batteryStatus = this.registerReceiver(null, ifilter);

if(batteryStatus != null) {

baInfo();

}

// 以降は Lollipop と機種によるサポートの違いあり

bManager = (BatteryManager)this.getSystemService(Context.BATTERY_SERVICE);

if(bManager != null){

batteryAgeing();

}

TextView textView = findViewById(R.id.text_view);

textView.setText(sbuilder);

}

private void baInfo(){

// Battery Level

int level = batteryStatus.getIntExtra(

BatteryManager.EXTRA_LEVEL, -1);

sbuilder.append("Level: ");

sbuilder.append(level);

sbuilder.append("\n");

// Battery Health

int bh = batteryStatus.getIntExtra(

BatteryManager.EXTRA_HEALTH, -1);

sbuilder.append("Health: ");

sbuilder.append(batteryHealth(bh));

sbuilder.append("\n");

// icon ID

int bi = batteryStatus.getIntExtra(

BatteryManager.EXTRA_ICON_SMALL, -1);

sbuilder.append("Icon: ");

sbuilder.append(bi);

sbuilder.append("\n");

// Battery plugged

int bpl = batteryStatus.getIntExtra(

BatteryManager.EXTRA_PLUGGED, -1);

sbuilder.append("Plugged: ");

sbuilder.append(batteryPluggCheck(bpl));

sbuilder.append("\n");

// Battery present or not

boolean bpr = batteryStatus.getBooleanExtra(

BatteryManager.EXTRA_PRESENT, false);

sbuilder.append("Present: ");

sbuilder.append(batteryPresent(bpr));

sbuilder.append("\n");

// scale

int bsc = batteryStatus.getIntExtra(

BatteryManager.EXTRA_SCALE, -1);

sbuilder.append("Scale: ");

sbuilder.append(bsc);

sbuilder.append("\n");

// Battery status

int bst = batteryStatus.getIntExtra(

BatteryManager.EXTRA_STATUS, -1);

sbuilder.append("Status: ");

sbuilder.append(status(bst));

sbuilder.append("\n");

// Battery technology

String bte = batteryStatus.getStringExtra(

BatteryManager.EXTRA_TECHNOLOGY);

sbuilder.append("Technology: ");

sbuilder.append(bte);

sbuilder.append("\n");

// temperature

int btp = batteryStatus.getIntExtra(

BatteryManager.EXTRA_TEMPERATURE, -1);

sbuilder.append("Tempareture: ");

sbuilder.append((float)btp/10);

sbuilder.append(" ℃\n");

// Voltage

int bv = batteryStatus.getIntExtra(

BatteryManager.EXTRA_VOLTAGE, -1);

sbuilder.append("Voltage: ");

sbuilder.append((float)bv/1000);

sbuilder.append(" [v]\n\n");

}

private String batteryHealth(int bh){

String health = null;

if(bh == BatteryManager.BATTERY_HEALTH_GOOD){

health = "GOOD";

}

else if(bh == BatteryManager.BATTERY_HEALTH_DEAD){

health = "DEAD";

}

else if(bh == BatteryManager.BATTERY_HEALTH_COLD){

health = "COLD";

}

else if(bh == BatteryManager.BATTERY_HEALTH_OVERHEAT){

health = "OVERHEAT";

}

else if(bh == BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE){

health = "OVER_VOLTAGE";

}

else if(bh == BatteryManager.BATTERY_HEALTH_UNKNOWN){

health = "UNKNOWN";

}

else if(bh == BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE){

health = "UNSPECIFIED_FAILURE";

}

return health;

}

private String batteryPluggCheck(int bpl){

String plugged = "NOT PLUGGED";

if(bpl == BatteryManager.BATTERY_PLUGGED_AC){

plugged = "PLUGGED AC";

}

else if(bpl == BatteryManager.BATTERY_PLUGGED_USB){

plugged = "PLUGGED USB";

}

else if(bpl == BatteryManager.BATTERY_PLUGGED_WIRELESS){

plugged = "PLUGGED WIRELESS";

}

return plugged;

}

private String batteryPresent(boolean bpr){

String present;

if(bpr){

present = "PRESENT";

}

else{

present = "NOT PRESENT";

}

return present;

}

private String status(int bst){

String status = "?";

if(bst == BatteryManager.BATTERY_STATUS_CHARGING){

status = "CHARGING";

}

else if(bst == BatteryManager.BATTERY_STATUS_DISCHARGING){

status = "DISCHARGING";

}

else if(bst == BatteryManager.BATTERY_STATUS_FULL){

status = "FULL";

}

else if(bst == BatteryManager.BATTERY_STATUS_NOT_CHARGING){

status = "NOT CHARGING";

}

else if(bst == BatteryManager.BATTERY_STATUS_UNKNOWN){

status = "UNKNOWN";

}

return status;

}

private void batteryAgeing(){

// RemainingCapacityRatio

int remainingCapacityRatio = bManager.getIntProperty(

BatteryManager.BATTERY_PROPERTY_CAPACITY);

sbuilder.append("RemainingCapacityRatio: ");

sbuilder.append(remainingCapacityRatio);

sbuilder.append(" %\n");

// BatteryCapacityMicroAh

int batteryCapacityMicroAh = bManager.getIntProperty(

BatteryManager.BATTERY_PROPERTY_CHARGE_COUNTER);

sbuilder.append("BatteryCapacityMicroAh: ");

sbuilder.append(batteryCapacityMicroAh);

sbuilder.append(" uAh\n");

// DischargingTimeSeconds

int dischargingTimeSeconds = bManager.getIntProperty(

BatteryManager.BATTERY_PROPERTY_CURRENT_AVERAGE);

sbuilder.append("DischargingTimeSeconds: ");

sbuilder.append(dischargingTimeSeconds);

sbuilder.append(" msec\n");

// Current

int currentNow = bManager.getIntProperty(

BatteryManager.BATTERY_PROPERTY_CURRENT_NOW);

sbuilder.append("CurrentNow: ");

sbuilder.append(currentNow);

sbuilder.append(" uA\n");

// EnergyCounter

long energyCounter = bManager.getLongProperty(

BatteryManager.BATTERY_PROPERTY_ENERGY_COUNTER);

sbuilder.append("EnergyCounter: ");

sbuilder.append(energyCounter);

sbuilder.append(" nWh\n\n");

}

　
Android機により一部の機能のみの実装だったりと機種次第のところがあります。いずれこれが実装されれば便利なアプリが作れそうです。
　
activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:background="#dfe"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/text_view"
        android:textSize="20sp"
        android:textColor="#000"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:padding="16dp"

android:background="#dfe"

tools:context=".MainActivity">

<TextView

android:id="@+id/text_view"

android:textSize="20sp"

android:textColor="#000"

android:layout_width="wrap_content"

android:layout_height="wrap_content" />

</RelativeLayout>

　
基本的にバッテリー残量などの外部デバイスを使う場合は実機に依存する部分があることを前提にすべきですが、Android Studio 2.0からemulatorである程度確認することができます。

バッテリー残量やその他のステータスを変更して試せます。