加载Web视图后，如何使进度条消失？

Question

I am developing the WebView for my project. I have used the WebView with progress bar. The progress bar loads properly when WebView loads. After Loading the page the progress bar is not disappearing. How to make its visibility gone.

I will share the code. I have created webview with progress bar.

public class MainActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    String url = "https://rnbazar.com/";
    setContentView(R.layout.activity_main);
    final WebView myWebView = (WebView) findViewById(R.id.webview);
    WebSettings webSettings = myWebView.getSettings();
    webSettings.setJavaScriptEnabled(true);
    //myWebView.setWebViewClient(new WebViewClient());
    myWebView.getSettings().setUseWideViewPort(true);
    myWebView.getSettings().setLoadWithOverviewMode(true);
    myWebView.loadUrl(url);
    myWebView.setWebViewClient(new MyWebViewClient());

    myWebView.setWebViewClient(new WebViewClient() {
      @Override public void onReceivedError(WebView view, int errorCode,
        String description, String failingUrl) {
        myWebView.loadUrl("file:///android_asset/error.html");
      }
    });
  }

  private class MyWebViewClient extends WebViewClient {
    @Override
    public void onPageStarted(final WebView myWebView, final String url,
      final Bitmap favicon) {
      ProgressBar bar = (ProgressBar)
      myWebView.findViewById(R.id.progressBar);

      bar.setVisibility(View.VISIBLE);
      super.onPageStarted(myWebView, url, favicon);

    }

    @Override
    public boolean shouldOverrideUrlLoading(WebView myWebView, String url) {

      myWebView.loadUrl(url);
      return true;
    }

    @Override
    public void onPageFinished(WebView myWebView, String url) {
      ProgressBar bar = (ProgressBar)
      myWebView.findViewById(R.id.progressBar);
      super.onPageFinished(myWebView, url);
      bar.setVisibility(View.GONE);
    }

  }
}

I want to make disappear progress bar once page loads. if i click any link again loader comes & again disappears after page loads.

Answer 1

a WebView might with high probability not contain any R.id.progressBar ...

public class MainActivity extends Activity {

    private WebView mWebView = null;
    private Progressbar mProgressbar = null;
    private String url = "https://rnbazar.com/";

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.activity_main);

        this.mWebView = (WebView) findViewById(R.id.webview);
        this.mProgressbar = (Progressbar) findViewById(R.id.progressBar);
    }
    ...

and then you can use that reference:

private class MyWebViewClient extends WebViewClient {

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

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

    @Override
    public void onPageFinished(WebView webView, String url) {
        super.onPageFinished(webView, url);
        mProgressbar.setVisibility(View.GONE);
    }
}