當用戶脫機時顯示對話框，並在用戶脫機時關閉對話框（使用broadcastReceiver）

Question

這是我的基本活動，是課堂activity擴展。 我讓我的其他活動擴展了這個基類：

public abstract class Base extends Activity {

private BroadcastReceiver netStateReceiver;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(getLayoutResourceId());
}
protected abstract int getLayoutResourceId();

@Override
protected void onPause() {
    if (netStateReceiver != null) {
        unregisterReceiver(netStateReceiver);
        netStateReceiver = null;
    }
    super.onPause();
}

@Override
protected void onResume() {
    if (netStateReceiver == null) {
        netStateReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(final Context context, Intent intent) {

                final Dialog offline = new Dialog(context, android.R.style.Theme_Light);

                //A change occurred in connection state. Check whether user has been become online or offline:
                if (!CheckNet()) {
                    //User became offline (show offline dialog):
                    offline.setContentView(R.layout.activity_offline);
                    offline.setTitle("offline");
                    offline.getWindow().setBackgroundDrawableResource(R.color.transparent);

                    offline.show();

                    final Button retry = (Button) offline.findViewById(R.id.button6);
                    retry.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            if (CheckNet()) {
                                offline.dismiss();
                            }
                        }
                    });

                }
                else {
                    //User became online (dismiss offline dialog):
                    if (offline.isShowing()) {
                        offline.dismiss();
                    }
                }
            }
        };
        registerReceiver(netStateReceiver, new IntentFilter(Values.CONNECTIVITY_RECEIVER_ACTION));
    }
    super.onResume();
}

private boolean CheckNet() {
    final ConnectivityManager conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    final NetworkInfo activeNetwork = conMgr.getActiveNetworkInfo();
    return (activeNetwork != null && activeNetwork.isConnectedOrConnecting());
}
}

如您在代碼中看到的，我已經注冊了一個用於檢查連接狀態的接收器。

我希望當用戶脫機時向用戶顯示一個對話框，並通知他他已脫機，應該聯機后才能繼續。 這部分效果很好。

我還希望在顯示該對話框時以及在用戶聯機時將此對話框關閉，但是該部分不起作用並且對話框仍保留在顯示屏上。

有什么問題，如何關閉對話框？

Answer 1

您可以在每個廣播上創建一個新對話框，而不使用以前已經創建的對話框。

使對話框變量成為活動類的成員變量，然后它將起作用。

private Dialog offline;

@Override
protected void onResume() {
    if (netStateReceiver == null) {
        netStateReceiver = new BroadcastReceiver() {
            @Override
        public void onReceive(final Context context, Intent intent) {

            if (!CheckNet()) {
                if(offline==null || !offline.isShowing()){
                    offline = new Dialog(context, android.R.style.Theme_Light);
                }
                ...
            } else {
                //User became online (dismiss offline dialog):
                if (offline!=null && offline.isShowing()) {
                    offline.dismiss();
                }
            }

Answer 2

每次接收廣播時，您都在創建一個新對話框，因此您關閉的對話框與用於顯示“您當前處於離線狀態”的對話框完全不同。

嘗試將“離線”對話框放在活動中，而不是放在onReceive回調中。

一個簡單的例子是：

public abstract class Base extends Activity {

    private BroadcastReceiver netStateReceiver;

    final Dialog offline;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(getLayoutResourceId());

        // You create the dialog here instead within the onReceive callback
        offline = new Dialog(this, android.R.style.Theme_Light);
        offline.setContentView(R.layout.activity_offline);
        offline.setTitle("offline");
        offline.getWindow().setBackgroundDrawableResource(R.color.transparent);
    }


    @Override
    protected void onResume() {
        if (netStateReceiver == null) {
            netStateReceiver = new BroadcastReceiver() {
                @Override
                public void onReceive(final Context context, Intent intent) {
                    if (!CheckNet()) {
                        // Your dialog already exists, just show it immediately
                        offline.show();

                        final Button retry = (Button) offline.findViewById(R.id.button6);
                        retry.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                if (CheckNet()) {
                                    offline.dismiss();
                                }
                            }
                        });

                    }
                    else {
                        //User became online (dismiss offline dialog):
                        if (offline.isShowing()) {
                            offline.dismiss();
                        }
                    }
                }
            };
            registerReceiver(netStateReceiver, new IntentFilter(Values.CONNECTIVITY_RECEIVER_ACTION));
        }
        super.onResume();
    }
}

Answer 3

使它全局訪問您的對話框對象引用：

final Dialog offline = new Dialog(context, android.R.style.Theme_Light);

然后，您將能夠關閉對話框。