Android ViewPager + WebView, ClasscastException! Hai bisogno di WebView in un mirino

Question

Sto cercando di creare un "ListView" orizzontale di WebViews. Come suggerito da una precedente risposta a una domanda, sto usando la libreria ViewPager dal pacchetto di compatibilità.

Sfortunatamente quando vado ad aggiungere il mio webview alla raccolta di visualizzazioni, usando

((ViewPager) collection).addView((View)mainContent,0);

Ottengo il problema del casting.

09-07 20:45:30.690: ERROR/AndroidRuntime(8166): java.lang.ClassCastException: android.webkit.WebView cannot be cast to android.support.v4.view.ViewPager

Questo si blocca l'app.

Ora ha quasi senso, lanciare diversi tipi di dati rende le cose storte, ma in un'app Esempio di Viewpager che avevo, stanno lanciando TextView al Viewpager che è una vista ...

Semplicemente non so quale altro modo per "archiviare" le mie viste e mostrarle nell'app! io ho

private class AwesomePagerAdapter extends PagerAdapter{
    LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    @Override
    public int getCount() {
        return NUM_AWESOME_VIEWS;
    }


    @Override
    public Object instantiateItem(View collection, int position) {

        ViewPager viewPager = (ViewPager) collection;

        collection = layoutInflater.inflate(R.layout.maincontentview, null);

        WebView mainContent = (WebView)collection.findViewById(R.id.mainContent);

        JSInterface jsInterface = new JSInterface(mainContent);


        Display display = getWindowManager().getDefaultDisplay(); 
        int width = display.getWidth();
        int height = display.getHeight();
        //jsInterface.fit(width, height);
        //jsInterface.flip(width, height);

        WebSettings webSettings = mainContent.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setPluginsEnabled(true);
        webSettings.setLoadsImagesAutomatically(true);
        webSettings.setSupportZoom(false);

        mainContent.setVerticalScrollBarEnabled(false);
        mainContent.setHorizontalScrollBarEnabled(false);

        /*mainContent.setOnTouchListener(new View.OnTouchListener() {
            public boolean onTouch(View v, MotionEvent event) {
                return(event.getAction() == MotionEvent.ACTION_MOVE);
            }
        });*/

        mainContent.setWebViewClient(new WebViewClient()
        {
            @Override
            public void onPageFinished(WebView view, String url) 
            {
                 /*mainContent.loadUrl("javascript:var script = document.createElement('script');" +  
                            "script.type = 'text/javascript';" +
                            "script.src = 'jquery.min.js';" + 
                            "document.getElementsByTagName('head')[0].appendChild(script);");*/
                WebView mainContent = (WebView)view.findViewById(R.id.mainContent);
                 Display display = getWindowManager().getDefaultDisplay(); 
                 int width = display.getWidth();
                 int height = display.getHeight();
                 mainContent.loadUrl("javascript:fit("+width+","+height+");");
                 mainContent.loadUrl("javascript:flip("+width+","+height+");");

            }
        });

        mainContent.setWebChromeClient(new WebChromeClient()
        {
            @Override
            public boolean onJsAlert(WebView view, String url, String message, JsResult result) 
            {
                Log.e("alert triggered", message);
                return false;         
            }
        });

        //use load file from string, article[i].html
        mainContent.loadUrl("file:///android_asset/cache_manifest_test.html");

        ((ViewPager) collection).addView((View)mainContent,0);

        return mainContent;
    }

    /**
     * Remove a page for the given position.  The adapter is responsible
     * for removing the view from its container, although it only must ensure
     * this is done by the time it returns from {@link #finishUpdate()}.
     *
     * @param container The containing View from which the page will be removed.
     * @param position The page position to be removed.
     * @param object The same object that was returned by
     * {@link #instantiateItem(View, int)}.
     */
    @Override
    public void destroyItem(View collection, int position, Object view) {
        ((ViewPager) collection).removeView((WebView) view);
    }



    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view==((WebView)object);
    }


    /**
     * Called when the a change in the shown pages has been completed.  At this
     * point you must ensure that all of the pages have actually been added or
     * removed from the container as appropriate.
     * @param container The containing View which is displaying this adapter's
     * page views.
     */
    @Override
    public void finishUpdate(View arg0) {}


    @Override
    public void restoreState(Parcelable arg0, ClassLoader arg1) {}

    @Override
    public Parcelable saveState() {
        return null;
    }

    @Override
    public void startUpdate(View arg0) {}

}

Answer 1

Funziona ... Ho dovuto ridurre alcune cose di Webview mentre stavo ottenendo errori con quello.

Il problema principale che hai avuto era usare la vista "collezione" piuttosto che crearne una nuova.

package com.msi.awesomepager;

import android.app.Activity;
import android.content.Context;   
import android.os.Bundle;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.Display;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.JsResult;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.TextView;

public class AwesomePagerActivity extends Activity {

    private ViewPager awesomePager;
    private static int NUM_AWESOME_VIEWS = 20;
    private Context context;
    private AwesomePagerAdapter awesomeAdapter;
    LayoutInflater inflater ;



    /** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    context = this;

    inflater = (LayoutInflater)
            context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    awesomeAdapter = new AwesomePagerAdapter();
    awesomePager = (ViewPager) findViewById(R.id.awesomepager);
    awesomePager.setAdapter(awesomeAdapter);

}

private class AwesomePagerAdapter extends PagerAdapter{

    @Override
    public int getCount() {
        return NUM_AWESOME_VIEWS;
    }


    @Override
    public Object instantiateItem(View collection, int position) {

        View layout; 
        LayoutInflater mInflater =  (LayoutInflater)
                context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        layout  = mInflater.inflate(R.layout.maincontentview, null);

        WebView mainContent = (WebView)layout.findViewById(R.id.mainContent);

        mainContent.getSettings().setJavaScriptEnabled(true);

        WebSettings webSettings = mainContent.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setBuiltInZoomControls(true);
        mainContent.requestFocusFromTouch();

        mainContent.setWebViewClient(new WebViewClient());
        mainContent.setWebChromeClient(new WebChromeClient());

        mainContent.loadUrl("file:///android_asset/test.html");

        ((ViewPager) collection).addView((View)layout,0);

        return layout;
    }

    /**
     * Remove a page for the given position.  The adapter is responsible
     * for removing the view from its container, although it only must ensure
     * this is done by the time it returns from {@link #finishUpdate()}.
     *
     * @param container The containing View from which the page will be removed.
     * @param position The page position to be removed.
     * @param object The same object that was returned by
     * {@link #instantiateItem(View, int)}.
     */
    @Override
    public void destroyItem(View collection, int position, Object view) {
        ((ViewPager) collection).removeView((View) view);
    }



    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view==((View)object);
    }


    /**
     * Called when the a change in the shown pages has been completed.  At this
     * point you must ensure that all of the pages have actually been added or
     * removed from the container as appropriate.
     * @param container The containing View which is displaying this adapter's
     * page views.
     */
    @Override
    public void finishUpdate(View arg0) {}


    @Override
    public void restoreState(Parcelable arg0, ClassLoader arg1) {}

    @Override
    public Parcelable saveState() {
        return null;
    }

    @Override
    public void startUpdate(View arg0) {}

   }

}

Spero che sia di aiuto. M