Question

我正在尝试添加一个进度条，在应用启动后添加“正在加载...请等待”而不是webview应用上的白页。我能够做到但进度条加载而不停止。即使我从互联网断开连接后仍然可以不停地加载。我怎样才能确保如果连接进度条停止并且网站正常加载，而不是永远加载，它会告诉我“连接错误。再试一次。”

以下是我的代码：

    package com.ibra.ibrawebview;
    import android.app.ProgressDialog;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.KeyEvent;
    import android.webkit.WebView;
    import android.webkit.WebViewClient;
    import android.widget.Toast;
    import android.support.v7.app.AlertDialog;
    import android.content.DialogInterface;

    public class MainActivity extends AppCompatActivity {

        private WebView webView;
        private ProgressDialog progressDialog;



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


            webView = (WebView) findViewById(R.id.ibraWebView);
            webView.getSettings().setJavaScriptEnabled(true);
            progressDialog=new ProgressDialog(this);
            progressDialog.setMessage("Loading...Please wait");
            progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
            progressDialog.show();

            webView.setWebViewClient(new WebViewClient()
            {
                @Override
                public boolean shouldOverrideUrlLoading(WebView view, String url) {
                    view.loadUrl("http://www.google.com/");
                    return true;
                }

                @Override
                public void onPageFinished(WebView view, String url) {
                    super.onPageFinished(view, url);
                    if (progressDialog.isShowing()) {
                        progressDialog.dismiss();
                    }
                }
            });

    //give error message if no connection
            webView.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("Connection Problem");
                    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);
                }
            });//end of error message

            //begin progress bar


            //end of progress bar


        }
        //goback to previous page
        @Override
        public boolean onKeyDown(int keyCode, KeyEvent event) {
            if (event.getAction()==KeyEvent.ACTION_DOWN){
                switch (keyCode){
                    case KeyEvent.KEYCODE_BACK:
                        if (webView.canGoBack()){
                            webView.goBack();
                        }
                        else {
                            finish();
                        }
                        return true;
                }
            }
            return super.onKeyDown(keyCode, event);
        }



    }

Answer 1

试试这个

ProgressBar progressBar;
progressBar = (ProgressBar) findViewById(R.id.progressbar);
progressBar.setMax(100);
progressBar.setProgress(1);

  webView.setWebChromeClient(new WebChromeClient() {
        public void onProgressChanged(WebView view, int progress) {
            progressBar.setProgress(progress);
        }
    });

  webView.setWebViewClient(new WebViewClient() {

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


        }

        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            progressDialog.hide();
            progressBar.setVisibility(View.GONE);
        }
    });

Answer 2

创建一个方法checkConnection（），它告诉您互联网连接是否可用。这是你如何做到的：

private void checkConnection() {
    ConnectivityManager cm = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
    isConnected = false;
    if (activeNetwork != null && activeNetwork.isConnected()) {
        isConnected = true;



    } else {
        final AlertDialog.Builder builder = new AlertDialog.Builder(FeedbackActivity.this);
        builder.setTitle("Connection failed");
        builder.setMessage("The application without the internet connection may not work. Please check your internet connection.");
        builder.setIcon(android.R.drawable.ic_dialog_alert);
        builder.setCancelable(false);
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {

            public void onClick(DialogInterface dialog, int which) {

                checkConnection();
            }
        });
        builder.show();

    }
}

Answer 3

if (progressDialog.isShowing()) {
     progressDialog.dismiss();
 }

在显示无连接错误的同时使用此功能，因此android会删除进度条。

Answer 4

因为你有setWebViewClient两次。但只考虑一个。所以你只需要编写一个setWebViewClient并将所有覆盖方法（例如pageFinished，onRecievedError）放在其中。

无论是否有互联网，Android webview进度条都会持续加载

4 个答案: