Android WebView - 1st LoadData() works fine, subsequent calls do not update display

StackOverflow https://stackoverflow.com/questions/4096783

  •  28-09-2019
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Question

After the 1st call to LoadData() the event onLoadResource fires as it should and the display is fine. Next I want to refresh the screen with a new page, when I use LoadData() the second time the page does not update and onLoadResource() DOES NOT FIRE.

Then second call to LoadData() onlyfires onPageFinished ... onPageStarted never fires!

A work around was to call .reload() after LoadData() but that causes all sorts of problems during the other logic in the activity.

Why doesn't LoadData() work multiple times?

I am using extremely simple HTML, and since using .reload() makes it work my LoadData() statement doesn't seem to be the problem.

Any Ideas would be helpful, TIA

Was it helpful?

Solution

Use

webview.loadDataWithBaseURL("same://ur/l/tat/does/not/work", "data", "text/html", "utf-8", null);

it works fine. loaddata does not refresh next time the data is loaded.

OTHER TIPS

For some reason you have to clear the content first. The "load..." methods don't seem to be explicitly appending their content but it doesn't work. I think it used to be WebView.clearView() but that was deprecated. The doc for the deprecated method on the Android site actually tells you to use WebView.loadUrl("about:blank") as a replacement for that method. So...

WebView.loadUrl("about:blank");
WebView.loadData(data, mime, encoding);

...does the trick for me. It seems a little dirty but I wouldn't dare disobey Google! I'm not sure if anyone else is doing this but I am just loading a String in that I had read from an "asset." I'm using it to display help docs. So I'm not using any actual URL's; I'm just using the WebView as an HTML renderer.

Note: For those newbies out there (like me only about a month ago) make sure to replace "WebView" with an instance of your variable. These are not static methods.

Such approach will work

webView.loadDataWithBaseURL("fake-url", "<html></html>", "text/html", "UTF-8", null);
webView.loadData(htmlBuilder.toString(), "text/html", "UTF-8");

Those who are still having the issue i found a quick solution just use a handler for this

    Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            webView.loadDataWithBaseURL("", html, "text/html", "UTF-8", null);
        }
    }, 10) ;

You need to loadDataWithBaseURL in main thread

I was able to make the browser refresh on each update by giving the html document a different id each time: please see below at // WEBVIEW.

package com.example.scroll;
// philip r brenan at gmail.com, www.appaapps.com 
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.webkit.WebView;

public class MainActivity extends Activity
 {protected void onCreate(Bundle savedInstanceState)
   {super.onCreate(savedInstanceState);
    setContentView(new MyWebView(this)); 
   }
  class MyWebView extends WebView 
   {MyWebView(Context Context)
     {super(Context);
      getSettings().setJavaScriptEnabled(true);
      addJavascriptInterface(this, "Android");   
      new Thread()
       {public void run()
         {for(int j = 0; j < 100; ++j)
           {post(new Runnable()
             {public void run()
               {loadData(content(), "text/html", "utf-8"); // Display in browser
               }
             });    
            try {Thread.sleep(5000);} catch(Exception e) {}
           }  
         }
       }.start();
     } 
    int c = 0, C = 1;
    String content() 
     {final StringBuilder s = new StringBuilder();
      //s.append("<html id="+(C++)+"><body>"); // WEBVIEW REFRESHES CORRECTLY *************** 
      s.append("<html><body>");              // WEBVIEW DOES NOT REFRESH ******************

      s.append("<h1 id=11>1111</h1>");
      s.append("<script>location.href = '#22';</script>");
      for(int i = 0; i < 10; ++i) s.append("<p>"+c+c+c); ++c;

      s.append("<h1 id=22>2222</h1>");
      for(int i = 0; i < 10; ++i) s.append("<p>"+c+c+c); ++c;
      Log.e("AAAAAA", "content="+s.toString());
      s.append("</body></html>");
      return s.toString();
     }
   } 
 } 

String urlUnique = String.format("http://%s", java.util.UUID.randomUUID().toString());
                    webView.loadDataWithBaseURL(urlUnique, "<html></html>", "text/html", "UTF-8", null);
                    Thread.sleep(200);
                    webView.loadData(htmlData, "text/html", "UTF-8");
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