当用户离线时显示对话框并在用户在线时关闭它（使用 broadcastReceiver）

Question

这是我的基地 activity，延伸 class activity。我让我的其他活动扩展这个基础 class:

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());
}
}

正如您在代码中看到的那样，我已经注册了一个用于检查连接状态的接收器。

我希望当用户离线时向用户显示一个对话框并通知他他离线并且应该在线才能继续。这部分效果不错。

我还希望在显示该对话框时以及在用户上线时关闭该对话框，但这部分不起作用，对话框仍显示在屏幕上。

有什么问题，如何关闭对话框？

Answer 1

您每次收到广播时都会创建一个新对话，因此您关闭的对话与用于显示的对话完全不同"you are currently offline"。

尝试将 "offline" 对话框放在 activity 中，而不是放在 onReceive 回调中。

一个简单的例子是：

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 2

让它全局访问您的对话框对象引用：

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

然后您就可以关闭对话框了。

Answer 3

您在每次广播时创建一个新对话，而不是使用您之前创建的对话。

将dialog变量设为activityclass的成员变量，就可以了。

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();
                }
            }

当用户离线时显示对话框并在用户在线时关闭它（使用 broadcastReceiver）

Show dialog when user becomes offline and dismiss it when user becomes online (with broadcastReceiver)

java

android

dialog

broadcastreceiver