Android检查网络连接

我想创建一个使用互联网的应用程序，我试图创建一个功能，检查连接是否可用，如果它不是，去到一个活动，有一个重试按钮和解释。

附件是我的代码到目前为止，但我得到错误Syntax error, insert "}" to complete MethodBody.

现在我已经把这些放在试图让它工作，但到目前为止没有运气…任何帮助都将不胜感激。

public class TheEvoStikLeagueActivity extends Activity {
private final int SPLASH_DISPLAY_LENGHT = 3000;


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);


private boolean checkInternetConnection() {
ConnectivityManager conMgr = (ConnectivityManager) getSystemService (Context.CONNECTIVITY_SERVICE);
// ARE WE CONNECTED TO THE NET
if (conMgr.getActiveNetworkInfo() != null
&& conMgr.getActiveNetworkInfo().isAvailable()
&& conMgr.getActiveNetworkInfo().isConnected()) {


return true;


/* New Handler to start the Menu-Activity
* and close this Splash-Screen after some seconds.*/
new Handler().postDelayed(new Runnable() {
public void run() {
/* Create an Intent that will start the Menu-Activity. */
Intent mainIntent = new Intent(TheEvoStikLeagueActivity.this, IntroActivity.class);
TheEvoStikLeagueActivity.this.startActivity(mainIntent);
TheEvoStikLeagueActivity.this.finish();
}
}, SPLASH_DISPLAY_LENGHT);
} else {
return false;


Intent connectionIntent = new Intent(TheEvoStikLeagueActivity.this, HomeActivity.class);
TheEvoStikLeagueActivity.this.startActivity(connectionIntent);
TheEvoStikLeagueActivity.this.finish();
}
}
}
492413 次浏览
小开

不能在另一个方法中创建方法，不能将private boolean checkInternetConnection() {方法移出onCreate

小开
最佳答案

这个方法检查手机是否连接到互联网，如果连接则返回true:

private boolean isNetworkConnected() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);


return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected();
}

在清单,

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<强>编辑: 这个方法实际上检查设备是否连接到internet(有可能它连接到网络但没有连接到internet) 

public boolean isInternetAvailable() {
try {
InetAddress ipAddr = InetAddress.getByName("google.com");
//You can replace it with your name
return !ipAddr.equals("");


} catch (Exception e) {
return false;
}
}
小开

试试下面的代码:

public static boolean isNetworkAvailable(Context context) {
boolean outcome = false;


if (context != null) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);


NetworkInfo[] networkInfos = cm.getAllNetworkInfo();


for (NetworkInfo tempNetworkInfo : networkInfos) {




/**
* Can also check if the user is in roaming
*/
if (tempNetworkInfo.isConnected()) {
outcome = true;
break;
}
}
}


return outcome;
}
小开

检查以确保它是“连接”的;对网络:

public boolean isNetworkAvailable(Context context) {
ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
}

检查以确保它是“连接”的;对互联网来说:

public boolean isInternetAvailable() {
try {
InetAddress address = InetAddress.getByName("www.google.com");
return !address.equals("");
} catch (UnknownHostException e) {
// Log error
}
return false;
}

需要许可:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

https://stackoverflow.com/a/17583324/950427 < a href = " https://stackoverflow.com/a/17583324/950427 " > < / >

小开

“return”语句后，您不能再编写任何代码(不包括try-finally块)。 将新的活动代码移到return语句之前

小开 
public boolean checkInternetConnection(Context context) {
ConnectivityManager connectivity = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivity == null) {
return false;
} else {
NetworkInfo[] info = connectivity.getAllNetworkInfo();
if (info != null) {
for (int i = 0; i < info.length; i++){
if (info[i].getState()==NetworkInfo.State.CONNECTED){
return true;
}
}
}
}
return false;
}
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当您连接到Wi-Fi源或通过手机数据包时，上述方法都有效。但在Wi-Fi连接的情况下，有时你会被进一步要求登录，就像在咖啡馆一样。所以在这种情况下，你的应用程序将失败，因为你连接的是Wi-Fi源，而不是互联网。

这个方法很有效。

    public static boolean isConnected(Context context) {
ConnectivityManager cm = (ConnectivityManager)context
.getSystemService(Context.CONNECTIVITY_SERVICE);


NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
if (activeNetwork != null && activeNetwork.isConnected()) {
try {
URL url = new URL("http://www.google.com/");
HttpURLConnection urlc = (HttpURLConnection)url.openConnection();
urlc.setRequestProperty("User-Agent", "test");
urlc.setRequestProperty("Connection", "close");
urlc.setConnectTimeout(1000); // mTimeout is in seconds
urlc.connect();
if (urlc.getResponseCode() == 200) {
return true;
} else {
return false;
}
} catch (IOException e) {
Log.i("warning", "Error checking internet connection", e);
return false;
}
}


return false;


}

请在与主线程分开的线程中使用此线程，因为它会进行网络调用，如果不遵循将抛出networkkonmainthreadexception。

也不要把这个方法放在onCreate或任何其他方法中。把它放到一个类中并访问它。

小开

下面是我作为Utils类的一部分使用的函数:

public static boolean isNetworkConnected(Context context) {
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
return (cm.getActiveNetworkInfo() != null) && cm.getActiveNetworkInfo().isConnectedOrConnecting();
}

像这样使用它:Utils.isNetworkConnected(MainActivity.this);

小开

不需要太复杂。最简单和框架的方式是使用ACCESS_NETWORK_STATE权限并只创建一个connected方法

public boolean isOnline() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnectedOrConnecting();
}

如果你有特定的主机和连接类型(wifi/移动)，你也可以使用requestRouteToHost。

你还需要:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

在你的android清单中。

去这里获取更多详细信息

小开

这是处理所有情况的另一个选项:

public void isNetworkAvailable() {
ConnectivityManager connectivityManager = (ConnectivityManager) ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
if (activeNetworkInfo != null && activeNetworkInfo.isConnected()) {
} else {
Toast.makeText(ctx, "Internet Connection Is Required", Toast.LENGTH_LONG).show();


}
}
小开

1-创建新的Java文件(右键单击包。新建>类>命名文件ConnectionDetector.java

2-在文件中添加以下代码

package <add you package name> example com.example.example;


import android.content.Context;
import android.net.ConnectivityManager;


public class ConnectionDetector {


private Context mContext;


public ConnectionDetector(Context context){
this.mContext = context;
}


public boolean isConnectingToInternet(){


ConnectivityManager cm = (ConnectivityManager)mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
if(cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected() == true)
{
return true;
}


return false;


}
}

3-打开你的MainActivity.java -你想检查连接的活动，并执行以下操作

创建并定义函数。

ConnectionDetector mConnectionDetector;</pre>

在“OnCreate”中添加以下内容

mConnectionDetector = new ConnectionDetector(getApplicationContext());

C -检查连接使用以下步骤

if (mConnectionDetector.isConnectingToInternet() == false) {
//no connection- do something
} else {
//there is connection
}
小开

我的问题是IsInternetAvailable答案没有测试蜂窝网络，而只是在连接wifi的情况下。这个答案适用于wifi和移动数据:

如何检查网络连接启用或禁用在WIFI和3G(数据计划)在移动?< / >

小开

在清单

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

在代码中,

public static boolean isOnline(Context ctx) {
if (ctx == null)
return false;


ConnectivityManager cm =
(ConnectivityManager) ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()) {
return true;
}
return false;
}
小开

使用此代码检查网络连接

ConnectivityManager connectivityManager = (ConnectivityManager) ctx
.getSystemService(Context.CONNECTIVITY_SERVICE);
if ((connectivityManager
.getNetworkInfo(ConnectivityManager.TYPE_MOBILE) != null && connectivityManager
.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED)
|| (connectivityManager
.getNetworkInfo(ConnectivityManager.TYPE_WIFI) != null && connectivityManager
.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
.getState() == NetworkInfo.State.CONNECTED)) {
return true;
} else {
return false;
}
小开

检查网络可用在android与互联网数据速度。

public boolean isConnectingToInternet(){
ConnectivityManager connectivity = (ConnectivityManager) Login_Page.this.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivity != null)
{
NetworkInfo[] info = connectivity.getAllNetworkInfo();
if (info != null)
for (int i = 0; i < info.length; i++)
if (info[i].getState() == NetworkInfo.State.CONNECTED)
{
try
{
HttpURLConnection urlc = (HttpURLConnection) (new URL("http://www.google.com").openConnection());
urlc.setRequestProperty("User-Agent", "Test");
urlc.setRequestProperty("Connection", "close");
urlc.setConnectTimeout(500); //choose your own timeframe
urlc.setReadTimeout(500); //choose your own timeframe
urlc.connect();
int networkcode2 = urlc.getResponseCode();
return (urlc.getResponseCode() == 200);
} catch (IOException e)
{
return (false);  //connectivity exists, but no internet.
}
}


}
return false;
}

此函数返回true或false。 必须获得用户权限

    <uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
小开

您可以使用以下代码片段检查Internet连接。

这两种方式都很有用，你可以检查NETWORK的类型 连接是可用的，所以你可以这样做你的进程

你只需要复制下面的类，并直接粘贴在你的包。

/**
* @author Pratik Butani
*/
public class InternetConnection {


/**
* CHECK WHETHER INTERNET CONNECTION IS AVAILABLE OR NOT
*/
public static boolean checkConnection(Context context) {
final ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);


if (connMgr != null) {
NetworkInfo activeNetworkInfo = connMgr.getActiveNetworkInfo();


if (activeNetworkInfo != null) { // connected to the internet
// connected to the mobile provider's data plan
if (activeNetworkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
// connected to wifi
return true;
} else return activeNetworkInfo.getType() == ConnectivityManager.TYPE_MOBILE;
}
}
return false;
}
}

现在你可以用like:

if (InternetConnection.checkConnection(context)) {
// Its Available...
} else {
// Not Available...
}

别忘了征求同意:)

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

您可以根据自己的需求进行修改。

谢谢你！

小开

所有的官方方法只告诉一个设备是否对网络开放，
如果你的设备连接到Wifi，但Wifi没有连接到互联网，那么这些方法将会失败(发生了很多次)，没有内置的网络检测方法会告诉这种情况，所以创建了Async回调类，它将在onConnectionSuccess和onConnectionFail中返回

new CheckNetworkConnection(this, new CheckNetworkConnection.OnConnectionCallback() {


@Override
public void onConnectionSuccess() {
Toast.makeText(context, "onSuccess()", toast.LENGTH_SHORT).show();
}


@Override
public void onConnectionFail(String msg) {
Toast.makeText(context, "onFail()", toast.LENGTH_SHORT).show();
}
}).execute();

网络调用异步任务 

public class CheckNetworkConnection extends AsyncTask < Void, Void, Boolean > {
private OnConnectionCallback onConnectionCallback;
private Context context;


public CheckNetworkConnection(Context con, OnConnectionCallback onConnectionCallback) {
super();
this.onConnectionCallback = onConnectionCallback;
this.context = con;
}


@Override
protected void onPreExecute() {
super.onPreExecute();
}


@Override
protected Boolean doInBackground(Void...params) {
if (context == null)
return false;


boolean isConnected = new NetWorkInfoUtility().isNetWorkAvailableNow(context);
return isConnected;
}


@Override
protected void onPostExecute(Boolean b) {
super.onPostExecute(b);


if (b) {
onConnectionCallback.onConnectionSuccess();
} else {
String msg = "No Internet Connection";
if (context == null)
msg = "Context is null";
onConnectionCallback.onConnectionFail(msg);
}


}


public interface OnConnectionCallback {
void onConnectionSuccess();


void onConnectionFail(String errorMsg);
}
}

实际类将ping到服务器 

class NetWorkInfoUtility {


public boolean isWifiEnable() {
return isWifiEnable;
}


public void setIsWifiEnable(boolean isWifiEnable) {
this.isWifiEnable = isWifiEnable;
}


public boolean isMobileNetworkAvailable() {
return isMobileNetworkAvailable;
}


public void setIsMobileNetworkAvailable(boolean isMobileNetworkAvailable) {
this.isMobileNetworkAvailable = isMobileNetworkAvailable;
}


private boolean isWifiEnable = false;
private boolean isMobileNetworkAvailable = false;


public boolean isNetWorkAvailableNow(Context context) {
boolean isNetworkAvailable = false;


ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);


setIsWifiEnable(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnected());
setIsMobileNetworkAvailable(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnected());


if (isWifiEnable() || isMobileNetworkAvailable()) {
/*Sometime wifi is connected but service provider never connected to internet
so cross check one more time*/
if (isOnline())
isNetworkAvailable = true;
}


return isNetworkAvailable;
}


public boolean isOnline() {
/*Just to check Time delay*/
long t = Calendar.getInstance().getTimeInMillis();


Runtime runtime = Runtime.getRuntime();
try {
/*Pinging to Google server*/
Process ipProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
int exitValue = ipProcess.waitFor();
return (exitValue == 0);
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
long t2 = Calendar.getInstance().getTimeInMillis();
Log.i("NetWork check Time", (t2 - t) + "");
}
return false;
}
}
小开

你可以简单地ping一个像谷歌这样的在线网站:

public boolean isConnected() throws InterruptedException, IOException {
String command = "ping -c 1 google.com";
return Runtime.getRuntime().exec(command).waitFor() == 0;
}
小开

接受的答案的EDIT显示了如何检查internet上的某些内容是否可以到达。我不得不等了很长时间才得到答案，但事实并非如此(使用的是没有互联网连接的wifi)。不幸的是InetAddress。getByName没有超时参数，所以下面的代码围绕它工作:

private boolean internetConnectionAvailable(int timeOut) {
InetAddress inetAddress = null;
try {
Future<InetAddress> future = Executors.newSingleThreadExecutor().submit(new Callable<InetAddress>() {
@Override
public InetAddress call() {
try {
return InetAddress.getByName("google.com");
} catch (UnknownHostException e) {
return null;
}
}
});
inetAddress = future.get(timeOut, TimeUnit.MILLISECONDS);
future.cancel(true);
} catch (InterruptedException e) {
} catch (ExecutionException e) {
} catch (TimeoutException e) {
}
return inetAddress!=null && !inetAddress.equals("");
}
小开

使用这个方法:

public static boolean isOnline() {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
return netInfo != null && netInfo.isConnectedOrConnecting();
}

这是需要的权限:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

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