监听电池状态只需要接收Intent.ACTION_BATTERY_CHANGED的广播即可，当电池状态发生变化时会发出广播。

1.运行状态如下图：

（1）连接USB时的状态

（2）断开USB时的状态

2.实现代码如下，各个状态通过名字就很容易知道意思，BatteryManager类中定义了电池状态。

public class MainActivity extends Activity {

    private static final String TAG = "MainActivity";

    private TextView mTvVoltage;

    private TextView mTvTemperature;

    private TextView mTvLevel;

    private TextView mTvStatus;

    private TextView mTvHealth;

    private TextView mTvTechnology;

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		mTvVoltage = (TextView)findViewById(R.id.tv_voltage);

		mTvTemperature = (TextView)findViewById(R.id.tv_temperature);

		mTvLevel = (TextView)findViewById(R.id.tv_level);

		mTvStatus = (TextView)findViewById(R.id.tv_status);

		mTvHealth = (TextView)findViewById(R.id.tv_health);

		mTvTechnology = (TextView)findViewById(R.id.tv_technology);

		this.registerReceiver(this.mBatteryReceiver, new IntentFilter(

                Intent.ACTION_BATTERY_CHANGED));

	}

	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.main, menu);

		return true;

	}

	private BroadcastReceiver mBatteryReceiver = new BroadcastReceiver() {

        @Override

        public void onReceive(Context arg0, Intent arg1) {

            int voltage=arg1.getIntExtra(BatteryManager.EXTRA_VOLTAGE, 0);

            mTvVoltage.setText("电压：" + voltage / 1000 + "." + voltage % 1000 + "V");

            int temperature=arg1.getIntExtra(BatteryManager.EXTRA_TEMPERATURE,0);

            mTvTemperature.setText("温度：" + temperature / 10 + "." + temperature % 10 + "℃");

            if (temperature >= 300) {

                mTvTemperature.setTextColor(Color.RED);

            } else {

                mTvTemperature.setTextColor(Color.BLUE);

            }

            int level=arg1.getIntExtra(BatteryManager.EXTRA_LEVEL,0);

            int scale=arg1.getIntExtra(BatteryManager.EXTRA_SCALE,0);

            int levelPercent = (int)(((float)level / scale) * 100);

            mTvLevel.setText("电量：" + levelPercent + "%");

            if (level <= 10) {

                mTvLevel.setTextColor(Color.RED);

            } else {

                mTvLevel.setTextColor(Color.BLUE);

            }

            int status = arg1.getIntExtra(BatteryManager.EXTRA_STATUS, BatteryManager.BATTERY_STATUS_UNKNOWN);

            String strStatus = "未知状态";;

            switch (status) {

            case BatteryManager.BATTERY_STATUS_CHARGING:

                strStatus = "充电中……";

                break;

            case BatteryManager.BATTERY_STATUS_DISCHARGING:

                strStatus = "放电中……";

                break;

            case BatteryManager.BATTERY_STATUS_NOT_CHARGING:

                strStatus = "未充电";

                break;

            case BatteryManager.BATTERY_STATUS_FULL:

                strStatus = "充电完成";

                break;

            }

            mTvStatus.setText("状态：" + strStatus);

            int health = arg1.getIntExtra(BatteryManager.EXTRA_HEALTH, BatteryManager.BATTERY_HEALTH_UNKNOWN);

            String strHealth = "未知 :(";;

            switch (status) {

            case BatteryManager.BATTERY_HEALTH_GOOD:

                strHealth = "好 :)";

                break;

            case BatteryManager.BATTERY_HEALTH_OVERHEAT:

                strHealth = "过热！";

                break;

            case BatteryManager.BATTERY_HEALTH_DEAD: // 未充电时就会显示此状态，这是什么鬼？

                strHealth = "良好";

                break;

            case BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE:

                strHealth = "电压过高！";

                break;

            case BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE:

                strHealth = "未知 :(";

                break;

            case BatteryManager.BATTERY_HEALTH_COLD:

                strHealth = "过冷！";

                break;

            }

            mTvHealth.setText("健康状况：" + strHealth);

            String technology = arg1.getStringExtra(BatteryManager.EXTRA_TECHNOLOGY);

            mTvTechnology.setText("电池技术：" + technology);

        }

    };

}

3.Layout布局如下，很简单只有几个TextView：

<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:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

    <TextView

        android:id="@+id/tv_battery_status"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:textColor="#0000FF"

        android:textStyle="bold"

        android:text="@string/battery_status" />

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:orientation="vertical"

        android:layout_below="@id/tv_battery_status"

        >

        <TextView

            android:id="@+id/tv_voltage"

	        android:layout_width="wrap_content"

	        android:layout_height="wrap_content"

	        />

        <TextView

            android:id="@+id/tv_temperature"

	        android:layout_width="wrap_content"

	        android:layout_height="wrap_content"

	        />

         <TextView

            android:id="@+id/tv_level"

	        android:layout_width="wrap_content"

	        android:layout_height="wrap_content"

	        />

        <TextView

            android:id="@+id/tv_status"

	        android:layout_width="wrap_content"

	        android:layout_height="wrap_content"

	        />

        <TextView

            android:id="@+id/tv_health"

	        android:layout_width="wrap_content"

	        android:layout_height="wrap_content"

	        />

        <TextView

            android:id="@+id/tv_technology"

	        android:layout_width="wrap_content"

	        android:layout_height="wrap_content"

	        />

       </LinearLayout>

</RelativeLayout>