Android监听电池状态

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>