如何防止在没有互联网连接时点击url-android studio

我使用Android Studio在Android应用程序中转换我的网站。 我试图显示对话框时，没有互联网连接在开幕式上。它很好用

但问题是当应用程序仍在运行时，突然没有互联网连接。然后，如果单击url，webview将显示“网页不可用”

MainActivity.java

package com.example.myapp;

import android.graphics.Bitmap;
import android.provider.SyncStateContract;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.util.Log;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private WebView mywebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (!DetectConnection.checkInternetConnection(this)) {
            try {
                AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();

                alertDialog.setTitle("Info");
                alertDialog.setMessage("Internet non disponible, Verifiez votre connexion internet et réessayez");
                alertDialog.setIcon(android.R.drawable.ic_dialog_alert);
                alertDialog.setButton(DialogInterface.BUTTON_POSITIVE, "Réessayer", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                        startActivity(getIntent());
                    }
                });

                alertDialog.show();
            } catch (Exception e) {

            }
        } else {
            mywebView = (WebView) findViewById(R.id.webview);
            WebSettings webSettings = mywebView.getSettings();
            mywebView.loadUrl("https://myapp.com/");
            mywebView.setWebViewClient(new WebViewClient());
            mywebView.clearCache(true);
            mywebView.clearHistory();
            webSettings.setJavaScriptEnabled(true);
            webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
        }
    }

    public class myWebClient extends WebViewClient{
        @Override
        public void onPageStarted (WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
        }
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
           view.loadUrl(url);
           return true;
        }
    }

    @Override
    public void onBackPressed (){
        if(mywebView.canGoBack()){
            mywebView.goBack();
        } else {
            super.onBackPressed();
        }
    }
}

package com.example.mycollege;

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


public class DetectConnection {
    public static boolean checkInternetConnection(MainActivity context) {

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

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

DetectConnection.java

package com.example.myapp;

import android.graphics.Bitmap;
import android.provider.SyncStateContract;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.util.Log;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private WebView mywebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (!DetectConnection.checkInternetConnection(this)) {
            try {
                AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();

                alertDialog.setTitle("Info");
                alertDialog.setMessage("Internet non disponible, Verifiez votre connexion internet et réessayez");
                alertDialog.setIcon(android.R.drawable.ic_dialog_alert);
                alertDialog.setButton(DialogInterface.BUTTON_POSITIVE, "Réessayer", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                        startActivity(getIntent());
                    }
                });

                alertDialog.show();
            } catch (Exception e) {

            }
        } else {
            mywebView = (WebView) findViewById(R.id.webview);
            WebSettings webSettings = mywebView.getSettings();
            mywebView.loadUrl("https://myapp.com/");
            mywebView.setWebViewClient(new WebViewClient());
            mywebView.clearCache(true);
            mywebView.clearHistory();
            webSettings.setJavaScriptEnabled(true);
            webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
        }
    }

    public class myWebClient extends WebViewClient{
        @Override
        public void onPageStarted (WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
        }
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
           view.loadUrl(url);
           return true;
        }
    }

    @Override
    public void onBackPressed (){
        if(mywebView.canGoBack()){
            mywebView.goBack();
        } else {
            super.onBackPressed();
        }
    }
}

package com.example.mycollege;

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


public class DetectConnection {
    public static boolean checkInternetConnection(MainActivity context) {

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

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

我想知道如何防止在未检测到连接时单击将默认页面“网页不可用”替换为对话框“没有internet，请检查您的连接！”。

---

有什么想法吗？

您的myWebClient课程将类似于：

// Function to load all URLs in same webview
private class myWebClient extends WebViewClient {
  public boolean shouldOverrideUrlLoading(WebView view, String url) {
    if (!DetectConnection.checkInternetConnection(this)) {
      Toast.makeText(getApplicationContext(), "No Internet!", Toast.LENGTH_SHORT).show();
    } else {
      view.loadUrl(url);
    }     
    return true;
  }
}

检查内部的internet连接

应覆盖以下内容

---

谢谢。

首先：

在按钮的onClick方法中，首先检查internet是否可用

在活动中添加此方法：

  public static boolean isNetworkAvailable(Context context) {
    ConnectivityManager objConnectivityManager;
    try {
        objConnectivityManager = (ConnectivityManager) context.getSystemService(Activity.CONNECTIVITY_SERVICE);
        final boolean IsWifiAvailable = objConnectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnected();

        boolean IsInternetAvailable = false;
        if (objConnectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE) != null)
            IsInternetAvailable = objConnectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnected();
        if (IsWifiAvailable == true || IsInternetAvailable == true)
            return true;
        else
            return false;
    } catch (Exception e) {
        return false;
    }
}

然后在onClick中调用此方法

boolean isNetworkAvailable = CommonMethods.isNetworkAvailable(this);
        if (isNetworkAvailable){
            // Call the webpage
        }else {
            Toast.makeText(this, "No internet connection", Toast.LENGTH_SHORT).show();
        }

秒： 如果您询问有关-

您正在使用应用程序

internet连接已打开

但是服务器没有响应[没有互联网]

---

然后在webview上使用超时。请参阅

在单击时间时检查这两种方法，如果网络可用，则继续执行操作

1-用于检查连接：

private boolean isNetworkConnected() {
        ConnectivityManager cm = (ConnectivityManager) getContext().getSystemService(Context.CONNECTIVITY_SERVICE);
        return cm.getActiveNetworkInfo() != null;
    }

2-检查互联网：

public boolean internetIsConnected() {
        try {
            String command = "ping -c 1 google.com";
            return (Runtime.getRuntime().exec(command).waitFor() == 0);
        } catch (Exception e) {
            return false;
        }
    }

将权限添加到清单：

<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" />

我将其更改为sir@Pratik Butani，但它会显示以下消息“错误：不兼容的类型：MainActivity.myWebClient无法转换为MainActivity”。错误请参考中的“this”！检测连接。检查Internet连接（此）。有什么想法吗？将

this

更改为

MainActivity。我认为你应该学习一些基本概念，这些概念将有助于解决这类基本问题。我将此更改为MainActivity。这样就没有错误了。但这并不能解决问题。所以@Makarand先生，你叫什么CommonMethods？@MohamedFall CommonMethod是一个单独的类。为项目需要的常用方法创建。只需在其中复制并粘贴isNetworkAvailable方法，然后您就可以从任何地方调用它。