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MainActivity.java代码

package com.themeister.feed.it;

import java.util.Locale;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.widget.TextView;

public class MainActivity extends FragmentActivity implements
    ActionBar.TabListener {


/**
 * The {@link android.support.v4.view.PagerAdapter} that will provide
 * fragments for each of the sections. We use a
 * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
 * will keep every loaded fragment in memory. If this becomes too memory
 * intensive, it may be best to switch to a
 * {@link android.support.v4.app.FragmentStatePagerAdapter}.
 */
SectionsPagerAdapter mSectionsPagerAdapter;

/**
 * The {@link ViewPager} that will host the section contents.
 */
ViewPager mViewPager;

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

    // Set up the action bar.
    final ActionBar actionBar = getActionBar();
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Create the adapter that will return a fragment for each of the three
    // primary sections of the app.
    mSectionsPagerAdapter = new SectionsPagerAdapter(
            getSupportFragmentManager());

    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mSectionsPagerAdapter);

    // When swiping between different sections, select the corresponding
    // tab. We can also use ActionBar.Tab#select() to do this if we have
    // a reference to the Tab.
    mViewPager
            .setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
                @Override
                public void onPageSelected(int position) {
                    actionBar.setSelectedNavigationItem(position);
                }
            });

    // For each of the sections in the app, add a tab to the action bar.
    for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
        // Create a tab with text corresponding to the page title defined by
        // the adapter. Also specify this Activity object, which implements
        // the TabListener interface, as the callback (listener) for when
        // this tab is selected.
        actionBar.addTab(actionBar.newTab()
                .setText(mSectionsPagerAdapter.getPageTitle(i))
                .setTabListener(this));
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public void onTabSelected(ActionBar.Tab tab,
        FragmentTransaction fragmentTransaction) {
    // When the given tab is selected, switch to the corresponding page in
    // the ViewPager.
    mViewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(ActionBar.Tab tab,
        FragmentTransaction fragmentTransaction) {
}

@Override
public void onTabReselected(ActionBar.Tab tab,
        FragmentTransaction fragmentTransaction) {
}

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */
public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a DummySectionFragment (defined as a static inner class
        // below) with the page number as its lone argument.
        Fragment fragment = new DummySectionFragment();
        Bundle args = new Bundle();
        args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public int getCount() {
        // Show 3 total pages.
        return 3;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        Locale l = Locale.getDefault();
        switch (position) {
        case 0:
            return getString(R.string.title_section1).toUpperCase(l);
        case 1:
            return getString(R.string.title_section2).toUpperCase(l);
        case 2:
            return getString(R.string.title_section3).toUpperCase(l);
        }
        return null;
    }
}

/**
 * A dummy fragment representing a section of the app, but that simply
 * displays dummy text.
 */
public static class DummySectionFragment extends Fragment {
    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    public static final String ARG_SECTION_NUMBER = "section_number";

    public DummySectionFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main_dummy,
                container, false);
        View webView = inflater.inflate(R.layout.fragment_main_dummy,
                container, false);
        TextView dummyTextView = (TextView) rootView
                .findViewById(R.id.section_label);
        WebView wv = (WebView)rootView.findViewById(R.id.webView);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.loadUrl("http://www.stackoverflow.com");
        return rootView;
    }
}

}

活动主文件

<?xml version="1.0" encoding="utf-8"?> 
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                  android:layout_width="fill_parent"
                  android:layout_height="fill_parent"
                  android:weightSum="1"
                  android:orientation="vertical">       
    <WebView 
        android:id="@+id/webView"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="0.9"/>    
    <ProgressBar 
         android:id="@+id/progressbar"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_weight="0.1"         
        style="?android:attr/progressBarStyleHorizontal"/>
    <android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" />  
    </LinearLayout>

我想做的是出于测试目的，在我的应用程序中加载http://www.stackoverflow.com并在网站上导航。以下代码返回两个错误：

“无法从类型 Activity MainActivity.java /Feed.it/src/com/themeister/feed/it 第 168 行 Java 问题对非静态方法 findViewById(int) 进行静态引用”和“webView 无法解析 MainActivity。 java /Feed.it/src/com/themeister/feed/it line 169 Java Problem" 任何我能得到的帮助都是值得赞赏的

解决方案

你有这个

   WebView wv = (WebView)findViewById(R.id.webView);

在片段中。findViewById是您的活动类的方法。

我建议你在你的fragment xml中有webview并使用下面的

   WebView wv = (WebView)rootView.findViewById(R.id.webView);

编辑

代替

   WebView wv = (WebView)rootView.findViewById(R.id.webView);
   webView.getSettings().setJavaScriptEnabled(true);
   webView.loadUrl("http://www.stackoverflow.com");

经过

  WebView wv = (WebView)rootView.findViewById(R.id.webView);
  wv.getSettings().setJavaScriptEnabled(true);
  wv.loadUrl("http://www.stackoverflow.com");