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);
}
}
}
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();
}
}
我不知道出了什么问题，为什么当我按下后退按钮时，WebView 不会返回。请有人帮助我！谢谢！