以下是一个完整的 Android Kotlin 网络连接检测工具类：
- 添加权限
首先在 AndroidManifest.xml 中添加网络权限：
xml
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />- 网络连接工具类
kotlin
import android.content.Context
import android.net.ConnectivityManager
import android.net.Network
import android.net.NetworkCapabilities
import android.net.NetworkRequest
import android.os.Build
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
/**
* 网络连接状态工具类
* 支持实时监听网络状态变化
*/
object NetworkUtils {
private var connectivityManager: ConnectivityManager? = null
// 网络状态流，可以观察网络状态变化
private val _networkState = MutableStateFlow(false)
val networkState: StateFlow<Boolean> = _networkState
/**
* 初始化工具类
*/
fun initialize(context: Context) {
connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as? ConnectivityManager
updateNetworkState(context)
registerNetworkCallback(context)
}
/**
* 检查是否连接网络
*/
fun isNetworkConnected(context: Context): Boolean {
return try {
val cm = connectivityManager ?: context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
val network = cm.activeNetwork
val capabilities = cm.getNetworkCapabilities(network)
capabilities != null && (
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) ||
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) ||
capabilities.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET)
)
} else {
@Suppress("DEPRECATION")
val networkInfo = cm.activeNetworkInfo
networkInfo != null && networkInfo.isConnected
}
} catch (e: Exception) {
e.printStackTrace()
false
}
}
/**
* 检查是否是 WiFi 连接
*/
fun isWifiConnected(context: Context): Boolean {
return try {
val cm = connectivityManager ?: context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
val network = cm.activeNetwork
val capabilities = cm.getNetworkCapabilities(network)
capabilities?.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) == true
} else {
@Suppress("DEPRECATION")
val networkInfo = cm.activeNetworkInfo
networkInfo != null && networkInfo.isConnected && networkInfo.type == ConnectivityManager.TYPE_WIFI
}
} catch (e: Exception) {
e.printStackTrace()
false
}
}
/**
* 检查是否是移动数据连接
*/
fun isMobileDataConnected(context: Context): Boolean {
return try {
val cm = connectivityManager ?: context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
val network = cm.activeNetwork
val capabilities = cm.getNetworkCapabilities(network)
capabilities?.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) == true
} else {
@Suppress("DEPRECATION")
val networkInfo = cm.activeNetworkInfo
networkInfo != null && networkInfo.isConnected && networkInfo.type == ConnectivityManager.TYPE_MOBILE
}
} catch (e: Exception) {
e.printStackTrace()
false
}
}
/**
* 获取网络类型
*/
fun getNetworkType(context: Context): String {
return when {
isWifiConnected(context) -> "WiFi"
isMobileDataConnected(context) -> "Mobile"
else -> "No Network"
}
}
/**
* 注册网络状态监听
*/
private fun registerNetworkCallback(context: Context) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
val cm = connectivityManager ?: return
val networkRequest = NetworkRequest.Builder()
.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
.addTransportType(NetworkCapabilities.TRANSPORT_ETHERNET)
.build()
cm.registerNetworkCallback(networkRequest, object : ConnectivityManager.NetworkCallback() {
override fun onAvailable(network: Network) {
_networkState.value = true
}
override fun onLost(network: Network) {
_networkState.value = false
}
override fun onUnavailable() {
_networkState.value = false
}
})
}
}
/**
* 更新网络状态
*/
private fun updateNetworkState(context: Context) {
_networkState.value = isNetworkConnected(context)
}
}- 扩展函数
kotlin
/**
* Context 的扩展函数，简化调用
*/
fun Context.isNetworkConnected(): Boolean {
return NetworkUtils.isNetworkConnected(this)
}
fun Context.isWifiConnected(): Boolean {
return NetworkUtils.isWifiConnected(this)
}
fun Context.isMobileDataConnected(): Boolean {
return NetworkUtils.isMobileDataConnected(this)
}
fun Context.getNetworkType(): String {
return NetworkUtils.getNetworkType(this)
}- 使用示例
在 Application 中初始化：
kotlin
class MyApplication : Application() {
override fun onCreate() {
super.onCreate()
NetworkUtils.initialize(this)
}
}在 Activity/Fragment 中使用：
kotlin
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// 基本使用
checkNetworkStatus()
// 观察网络状态变化
observeNetworkState()
}
/**
* 检查当前网络状态
*/
private fun checkNetworkStatus() {
if (isNetworkConnected()) {
val networkType = getNetworkType()
Toast.makeText(this, "网络已连接 - $networkType", Toast.LENGTH_SHORT).show()
} else {
Toast.makeText(this, "网络未连接", Toast.LENGTH_SHORT).show()
}
// 或者使用工具类直接调用
if (NetworkUtils.isNetworkConnected(this)) {
// 执行网络请求
}
}
/**
* 观察网络状态变化
*/
private fun observeNetworkState() {
lifecycleScope.launch {
NetworkUtils.networkState.collect { isConnected ->
if (isConnected) {
// 网络恢复
showNetworkRestored()
} else {
// 网络断开
showNetworkLost()
}
}
}
}
private fun showNetworkRestored() {
// 显示网络恢复提示
Snackbar.make(findViewById(android.R.id.content),
"网络已恢复", Snackbar.LENGTH_SHORT).show()
}
private fun showNetworkLost() {
// 显示网络断开提示
Snackbar.make(findViewById(android.R.id.content),
"网络连接已断开", Snackbar.LENGTH_LONG).show()
}
}在网络请求前检查：
kotlin
class UserRepository(private val context: Context) {
suspend fun fetchUserData(): Result<User> {
// 在发起网络请求前检查网络
if (!context.isNetworkConnected()) {
return Result.failure(IOException("网络未连接"))
}
return try {
// 执行网络请求
val response = apiService.getUser()
Result.success(response)
} catch (e: Exception) {
Result.failure(e)
}
}
}- 高级功能 - 网络状态监听器
如果需要更详细的回调，可以添加监听器：
kotlin
interface NetworkStateListener {
fun onNetworkAvailable(networkType: String)
fun onNetworkLost()
fun onNetworkTypeChanged(networkType: String)
}
class AdvancedNetworkMonitor(private val context: Context) {
private val listeners = mutableSetOf<NetworkStateListener>()
private var lastNetworkType = ""
init {
observeNetworkState()
}
private fun observeNetworkState() {
lifecycleScope.launch {
NetworkUtils.networkState.collect { isConnected ->
val currentType = context.getNetworkType()
if (isConnected) {
listeners.forEach { it.onNetworkAvailable(currentType) }
if (lastNetworkType != currentType) {
listeners.forEach { it.onNetworkTypeChanged(currentType) }
}
} else {
listeners.forEach { it.onNetworkLost() }
}
lastNetworkType = currentType
}
}
}
fun addListener(listener: NetworkStateListener) {
listeners.add(listener)
}
fun removeListener(listener: NetworkStateListener) {
listeners.remove(listener)
}
}这个工具类提供了：
· ✅ 检测网络连接状态
· ✅ 区分 WiFi 和移动数据
· ✅ 实时网络状态监听
· ✅ 简洁的 API 调用
· ✅ 支持协程 StateFlow
· ✅ 兼容不同 Android 版本
可以直接在项目中使用，确保在网络请求前进行连接检查！