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("電壓：" + voltage / 1000 + "." + voltage % 1000 + "V");               int temperature=arg1.getIntExtra(BatteryManager.EXTRA_TEMPERATURE,0);       mTvTemperature.setText("溫度：" + 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("電量：" + 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 = "未知狀態";;       switch (status) {       case BatteryManager.BATTERY_STATUS_CHARGING:         strStatus = "充電中……";         break;       case BatteryManager.BATTERY_STATUS_DISCHARGING:         strStatus = "放電中……";         break;       case BatteryManager.BATTERY_STATUS_NOT_CHARGING:         strStatus = "未充電";         break;       case BatteryManager.BATTERY_STATUS_FULL:         strStatus = "充電完成";         break;       }       mTvStatus.setText("狀態：" + 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 = "過熱！";         break;       case BatteryManager.BATTERY_HEALTH_DEAD: // 未充電時就會顯示此狀態，這是什么鬼？         strHealth = "良好";         break;       case BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE:         strHealth = "電壓過高！";         break;       case BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE:         strHealth = "未知 :(";         break;       case BatteryManager.BATTERY_HEALTH_COLD:         strHealth = "過冷！";         break;       }       mTvHealth.setText("健康狀況：" + strHealth);              String technology = arg1.getStringExtra(BatteryManager.EXTRA_TECHNOLOGY);       mTvTechnology.setText("電池技術：" + technology);     }   }; }

<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>