接收充电状态和电量的系统广播_broadcastreceiver 只有充电才执行

public class BroadcastR_PowerListener extends BroadcastReceiver {
 
    private static final String ACTION_POWER_CONNECTED = "android.intent.action.ACTION_POWER_CONNECTED";
    private static final String ACTION_POWER_DISCONNECTED = "android.intent.action.ACTION_POWER_DISCONNECTED";
 
    private static final String POWER_LOG_PATH = "Cache";
 
    private static BroadcastReceiver instance = null;
 
    private BroadcastR_PowerListener() {
 
    }
 
    public static void registerPowerListener() {
        if (instance == null) {
            instance = new BroadcastR_PowerListener();
            IntentFilter intentFilter = new IntentFilter();
 
            intentFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
            intentFilter.addAction(ACTION_POWER_CONNECTED);
            intentFilter.addAction(ACTION_POWER_DISCONNECTED);
 
            intentFilter.setPriority(Integer.MAX_VALUE);
            MyApplication.getInstance().registerReceiver(instance, intentFilter);
        }
    }
 
    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)) {
            //你可以读到充电状态,如果在充电，可以读到是usb还是交流电
 
            // 是否在充电
            int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
 
            boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
                    status == BatteryManager.BATTERY_STATUS_FULL;
 
            // 怎么充
            int chargePlug = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
            boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB;
            boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC;
 
            String fileName = String.format("uid_%d_power.txt", User.getUid());
            int powerLevel = intent.getIntExtra("level", 0);
            if (usbCharge) {
                write(powerLevel+"", POWER_LOG_PATH, fileName);
            }
 
        } else if (intent.getAction().equals(ACTION_POWER_CONNECTED)) {
            ErrRpt.debug("powerlistener", "Power Connected.");
        } else if (intent.getAction().equals(ACTION_POWER_DISCONNECTED)) {
            ErrRpt.debug("powerlistener", "Power DisConnected.");
        }
    }
 
    private void write(String content, String directory, String fileName) {
 
        try {
 
            File dir = new File(Environment.getExternalStorageDirectory()
                    + "/" + directory);
            File file = new File(dir + "/" + fileName);
 
            if (!dir.exists()) {
                dir.mkdirs();
            }
 
            if (!file.exists()) {
                try {
                    file.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            //true: append 追加的方式打开
            FileOutputStream fouts = new FileOutputStream(file, false);
            //将FileOutputStream包装成PrintStream
            PrintStream ps = new PrintStream(fouts);
            //输出文件内容
            ps.print(content);
 
            ps.close();
            fouts.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}