Question

看起来我已经非常接近我的WebView片段返回问题的解决方案了。这是我的活动代码：

package com.fragmentwebtest;

import java.util.ArrayList;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
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.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.view.KeyEvent;

public class TestSwipeABActivity extends FragmentActivity {

FragmentTransaction transaction;
static ViewPager mViewPager;
/** Called when the activity is first created. */
Fragment tabOneFragment = new TabOne();
Fragment tabTwoFragment = new TabTwo();
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    PagerAdapter mPagerAdapter = new PagerAdapter(getSupportFragmentManager());
    mPagerAdapter.addFragment(tabOneFragment);
    mPagerAdapter.addFragment(tabTwoFragment);

    //transaction = getSupportFragmentManager().beginTransaction();

    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mPagerAdapter);
    mViewPager.setOffscreenPageLimit(2);
    mViewPager.setCurrentItem(0);

    mViewPager.setOnPageChangeListener(
            new ViewPager.SimpleOnPageChangeListener() {
                @Override
                public void onPageSelected(int position) {
                    // When swiping between pages, select the
                    // corresponding tab.
                    getActionBar().setSelectedNavigationItem(position);
                }
            });

    ActionBar ab = getActionBar();
    ab.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    Tab tab1 = ab.newTab().setText("Tab One")
            .setTabListener(new TabListener<TabOne>(
                    this, "tabone", TabOne.class));

    Tab tab2 = ab.newTab().setText("Tab Two")
            .setTabListener(new TabListener<TabTwo>(
                    this, "tabtwo", TabTwo.class));

    ab.addTab(tab1);
    ab.addTab(tab2);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)  {
    if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

@Override
public void onBackPressed(){
    if ( (TabOne) tabOneFragment != null )
        ( (TabOne) tabOneFragment).onBackPressed();
    else
        super.onBackPressed();
}

public static class TabListener<T extends Fragment> implements ActionBar.TabListener {
    private Fragment mFragment;
    private final Activity mActivity;
    private final String mTag;
    private final Class<T> mClass;

    /** Constructor used each time a new tab is created.
      * @param activity  The host Activity, used to instantiate the fragment
      * @param tag  The identifier tag for the fragment
      * @param clz  The fragment's Class, used to instantiate the fragment
      */
    public TabListener(Activity activity, String tag, Class<T> clz) {
        mActivity = activity;
        mTag = tag;
        mClass = clz;
    }

    /* The following are each of the ActionBar.TabListener callbacks */

    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // Check if the fragment is already initialized
        if (mFragment == null) {
            // If not, instantiate and add it to the activity
            mFragment = Fragment.instantiate(mActivity, mClass.getName());
            ft.add(android.R.id.content, mFragment, mTag);
        } else {
            // If it exists, simply attach it in order to show it
            ft.attach(mFragment);
        }
    }

    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        if (mFragment != null) {
            // Detach the fragment, because another one is being attached
            ft.detach(mFragment);
        }
    }

    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // User selected the already selected tab. Usually do nothing.
    }

    public void onTabReselected(Tab arg0,
            android.app.FragmentTransaction arg1)
    {
        // TODO Auto-generated method stub

    }

    public void onTabSelected(Tab arg0, android.app.FragmentTransaction arg1)
    {
        // TODO Auto-generated method stub
        mViewPager.setCurrentItem(arg0.getPosition());
    }

    public void onTabUnselected(Tab arg0,
            android.app.FragmentTransaction arg1)
    {
        // TODO Auto-generated method stub

    }
}

public class PagerAdapter extends FragmentPagerAdapter {

    private final ArrayList<Fragment> mFragments = new ArrayList<Fragment>();

    public PagerAdapter(FragmentManager manager) {
        super(manager);
    }

    public void addFragment(Fragment fragment) {
        mFragments.add(fragment);
        notifyDataSetChanged();
    }

    @Override
    public int getCount() {
        return mFragments.size();
    }

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }
}

}

很好，现在是TabOne片段：

package com.fragmentwebtest;

import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.app.Fragment;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnKeyListener;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class TabOne extends Fragment
{
 private WebView myWebView;
 @Override
    public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    }

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState)
{
    View view = inflater.inflate(R.layout.tabone, container, false);
    myWebView = (WebView) view.findViewById(R.id.webview);
    myWebView.getSettings().setPluginsEnabled(true);
    myWebView.loadUrl("http://m.stirileprotv.ro");
    myWebView.setWebViewClient(new WebViewClient() {
    @Override public boolean shouldOverrideUrlLoading(WebView view, String url) {
            if (Uri.parse(url).getHost().equals("m.stirileprotv.ro")) {
                myWebView.loadUrl(url);
                return true;
            }
            else
            {
                return false;
            }
         }
    });
    return view;
}
public void onBackPressed() {
    if (getActivity() == null)
        return;
    if (myWebView != null && myWebView.canGoBack()) {
        myWebView.goBack();
    } else
        getActivity().finish();
}
}

我找不到有什么问题，为什么当我按下后退按钮时，WebView将不会返回。请有人帮帮我！谢谢！

Answer 1

活动中的onKeyDown完全禁止后退键，因为如果事件来自后退键，则始终只返回true。所以onBackPressed永远不会被调用。

请改为尝试：

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)  {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        onBackPressed();
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

WebView：我做错了什么？

1 个答案: