如何检测何时电池电量低：Android？

在代码中而不是在

AndroidManifest

registerReceiver(batteryChangeReceiver, new IntentFilter(    Intent.ACTION_BATTERY_CHANGED)); // register in activity or servicepublic class BatteryChangeReceiver extends BroadcastReceiver {    int scale = -1;    int level = -1;    int voltage = -1;    int temp = -1;    @Override    public void onReceive(Context context, Intent intent) {        level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);        scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);        temp = intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE, -1);        voltage = intent.getIntExtra(BatteryManager.EXTRA_VOLTAGE, -1);    }}unregisterReceiver(batteryChangeReceiver);//unregister in the activity or service

或使用

null

Intent BATTERYintent = this.registerReceiver(null, new IntentFilter(        Intent.ACTION_BATTERY_CHANGED));int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);Log.v(null, "LEVEL" + level);