Question

此代码应该建议手机是否正在实时充电，更改文本视图。

public class MainActivity extends AppCompatActivity {
TextView testoStatoCarica;
String positivo = "Sto caricando";
String negativo = "Non in carica";
boolean variabileStato;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    testoStatoCarica = (TextView) findViewById(R.id.TestoStatoCarica);


    //Ricevo lo stato di carica
    registerReceiver( null ,new IntentFilter("broadcastStato"));

    BroadcastReceiver ricettore =  new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Bundle b1 = intent.getExtras();
            variabileStato = intent.getBooleanExtra("isCharging", isCharging);
        }
    };


}
}

在另一个类（PowerConnectionReceiver）中我做了这个！

public class PowerConnectionReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
    int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
    boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
            status == BatteryManager.BATTERY_STATUS_FULL;

    int chargePlug = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
    boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB;
    boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC;

    Bundle bundle = intent.getExtras();

    Intent i1 = new Intent("broadcastStato");
    i1.putExtra("isCharging", isCharging);
    Intent i2 = new Intent("broadcastTipo1");
    i2.putExtra("usbCharge", usbCharge);
    Intent i3 = new Intent("broadcastTipo2");
    i3.putExtra("acCharge", acCharge);

    context.sendBroadcast(i1);
    context.sendBroadcast(i2);
    context.sendBroadcast(i3);
}
}

现在，问题在于我真的不明白在我的MainActivity中做了什么，并且在最后一堂课中创造了booleand！有人可以帮忙吗？

Answer 1

查看Monitoring the Battery Level and Charging State文章，其中包含代码示例：

首先，您需要在BroadcastReceiver中指定AndroidManifest：

<receiver android:name=".PowerConnectionReceiver">
  <intent-filter>
    <action android:name="android.intent.action.ACTION_POWER_CONNECTED"/>
    <action android:name="android.intent.action.ACTION_POWER_DISCONNECTED"/>
  </intent-filter>
</receiver>

然后，指定PowerConnectionReceiver：

public class PowerConnectionReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
        boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
                            status == BatteryManager.BATTERY_STATUS_FULL;

        int chargePlug = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
        boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB;
        boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC;
    }
}

现在，将新值从PowerConnectionReceiver传递到MainActivity的最后一步：您可以在此处找到该教程：https://trinitytuts.com/pass-data-from-broadcast-receiver-to-activity-without-reopening-activity/

（一旦您传递了新值 - 您可以更新TextView的文字）

就是这样！我希望，这有帮助

为什么我的文字视图没有变化？

1 个答案: