Question

我想创建一个Android服务，它会在断开连接并再次重新连接互联网时通知主要活动。我有以下检查互联网连接的功能：。

private boolean haveInternet(){
        NetworkInfo info=(NetworkInfo)((ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();

        if(info==null || !info.isConnected()){
            return false;
        }
        if(info.isRoaming()){
            //here is the roaming option you can change it if you want to disable internet while roaming, just return false
            return true;
        }
        return true;
    }

但我想知道如何在服务中使用它。

Answer 1

服务专为长期运行任务而设计。您应该使用BroadcastReceiver：

这是我用来监控网络状态进入主Activity的示例方法：

private void installListener() {

        if (broadcastReceiver == null) {

            broadcastReceiver = new BroadcastReceiver() {

                @Override
                public void onReceive(Context context, Intent intent) {

                    Bundle extras = intent.getExtras();

                    NetworkInfo info = (NetworkInfo) extras
                            .getParcelable("networkInfo");

                    State state = info.getState();
                    Log.d("InternalBroadcastReceiver", info.toString() + " "
                            + state.toString());

                    if (state == State.CONNECTED) {

                        onNetworkUp();

                    } else {

                        onNetworkDown();

                    }

                }
            };

            final IntentFilter intentFilter = new IntentFilter();
            intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
            registerReceiver(broadcastReceiver, intentFilter);
        }
    }

记得在onDestroy事件发生时调用unregisterReceiver

希望得到这个帮助。

Answer 2

这是 Kotlin版本，遵循Francesco Laurita的解决方案：

private val broadcastReceiver by lazy {
    NetworkListener.create({
        btnOnlineVideos.visibility = View.VISIBLE
    }, {
        btnOnlineVideos.visibility = View.GONE
    })
}

override fun onResume() {
    super.onResume()

    NetworkListener.register(this, broadcastReceiver)
}

override fun onPause() {
    super.onPause()

    NetworkListener.unregister(this, broadcastReceiver)
}

为此，我只需覆盖onResume和onPause方法，即可注册和注销BroadcastReceiver。

这是如何工作的？

我创建了以下类，该类有助于初始化，注册和注销BroadcastReceiver。这样，就无需重复大多数样板代码。

package com.programacionymas.app.services

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.net.ConnectivityManager
import android.net.NetworkInfo
import android.os.Parcelable
import android.util.Log

object NetworkListener {

    fun create(onNetworkUp: () -> Unit, onNetworkDown: () -> Unit): BroadcastReceiver {
        return object : BroadcastReceiver() {
            override fun onReceive(context: Context, intent: Intent) {

                intent.extras?.getParcelable<Parcelable>("networkInfo")?.let {
                    val info = it as NetworkInfo
                    val state: NetworkInfo.State = info.state

                    Log.d("BroadcastReceiver", "$info $state")
                    if (state === NetworkInfo.State.CONNECTED) {
                        onNetworkUp()
                    } else {
                        onNetworkDown()
                    }
                }

            }
        }
    }

    fun register(context: Context, broadcastReceiver: BroadcastReceiver) {
        val intentFilter = IntentFilter()
        intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION)
        context.registerReceiver(broadcastReceiver, intentFilter)
    }

    fun unregister(context: Context, broadcastReceiver: BroadcastReceiver) {
        context.unregisterReceiver(broadcastReceiver)
    }

}

如果只需要为一种状态执行语句，则也可以传递一个null匿名函数：

private val broadcastReceiver by lazy {
    NetworkListener.create(null, {
        toast(getString(R.string.check_your_internet))
        finish()
    })
}

并在create方法中将参数声明为可选参数：

fun create(onNetworkUp: (()->Unit)?, onNetworkDown: (()->Unit)?): BroadcastReceiver {/* ... */}

以及仅在将函数作为参数发送时才调用这些函数：

if (state === NetworkInfo.State.CONNECTED) {
    onNetworkUp?.invoke()
} else {
    onNetworkDown?.invoke()
}

Android服务检查互联网连接？

2 个答案: