Question

我的WebView-App出现问题。

我想在启动时添加一个“连接检查”，当没有可用的Internet连接或WebView超时时会弹出一个错误。我无法自己完成它，因为我是Android编程的新手。

我还想添加一个选项菜单，在这里我可以重新加载实际页面。

希望有人可以帮助我...

实际代码：

package com.sabithpkcmnr.webviewmaster;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.webkit.DownloadListener;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

ImageView superImageView;
ProgressBar superProgressBar;
WebView superWebView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    getSupportActionBar().setDisplayShowHomeEnabled(true);

    superImageView = findViewById(R.id.myImageView);
    superProgressBar = findViewById(R.id.myProgressBar);
    superWebView = findViewById(R.id.myWebView);

    superProgressBar.setMax(100);

    superWebView.loadUrl("http://google.com");
    superWebView.getSettings().setJavaScriptEnabled(true);
    superWebView.setWebViewClient(new WebViewClient() {

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);

        }
        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
        }
    });
    superWebView.setWebChromeClient(new WebChromeClient() {

        @Override
        public void onProgressChanged(WebView view, int newProgress) {
            super.onProgressChanged(view, newProgress);
            superProgressBar.setProgress(newProgress);
        }

        @Override
        public void onReceivedTitle(WebView view, String title) {
            super.onReceivedTitle(view, title);
            getSupportActionBar().setTitle(title);
        }

        @Override
        public void onReceivedIcon(WebView view, Bitmap icon) {
            super.onReceivedIcon(view, icon);
            superImageView.setImageBitmap(icon);

        }
    });

    superWebView.setDownloadListener(new DownloadListener() {
        @Override
        public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {
            Uri myUri = Uri.parse(url);
            Intent superIntent = new Intent(Intent.ACTION_VIEW);
            superIntent.setData(myUri);
            startActivity(superIntent);
        }
    });

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater myMenuInflater = getMenuInflater();
    myMenuInflater.inflate(R.menu.super_menu, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {

        case R.id.myMenuOne:
            onBackPressed();
            break;

        case R.id.myMenuTwo:
            GoForward();
            break;

        case R.id.myMenuThree:

            break;

    }
    return true;
}

private void GoForward() {
    if (superWebView.canGoForward()) {
        superWebView.goForward();
    } else {
        Toast.makeText(this, "Can't go further!", Toast.LENGTH_SHORT).show();
    }
}



@Override
public void onBackPressed() {
    if (superWebView.canGoBack()) {
        superWebView.goBack();
    } else {
        AlertDialog.Builder dialog = new AlertDialog.Builder(this);
        dialog.setTitle("(Exit?");
        dialog.setMessage("Name has nothing to go back, so what next?");
        dialog.setPositiveButton("EXIT ME", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                finish();
            }
        });
        dialog.setCancelable(false);
        dialog.setNegativeButton("STAY HERE", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        }).show();

    }
}
}

Answer 1

尝试以下方法，替换您的setWebViewClient，

superWebView= (WebView) findViewById(R.id.webView);
superWebView.setWebViewClient(new myWebClient());
superWebView.getSettings().setJavaScriptEnabled(true);
superWebView.loadUrl("LOAD_YOUR_URL");
superWebView.setWebViewClient(new WebViewClient() {
        public void onReceivedError(WebView webView, int errorCode, String description, String failingUrl) {
            try {
                webView.stopLoading();
            } catch (Exception e) {
            }

            if (webView.canGoBack()) {
                webView.goBack();
            }

            webView.loadUrl("about:blank");
            AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
            alertDialog.setTitle("Error");
            alertDialog.setMessage("Check your internet connection and try again.");
            alertDialog.setButton(DialogInterface.BUTTON_POSITIVE, "Try Again", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    finish();
                    startActivity(getIntent());
                }
            });

            alertDialog.show();
            super.onReceivedError(webView, errorCode, description, failingUrl);
        }
    });

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;

    }
}

Answer 2

以下方法可用于检查互联网连接。

public static boolean checkInternetConnection(Context context) {   

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

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

您可以在将URL加载到Webview中之前检查互联网连接。检查以下代码段。

if (checkInternetConnection(this)) {
superWebView.loadUrl("http://google.com");
}else{
 Toast.makeText(getApplicationContext(), "No Internet!", Toast.LENGTH_SHORT).show();
}

如果无法访问互联网，如何在WebView中添加网络错误消息

2 个答案: