我正在创建一个Android应用程序。在一个类中，我正在扩展片段，我在标题中收到错误。这是代码：
import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import ashat.jaiswal.trr.adapter.TabsPagerAdapter;
public class MoviesFragment extends Fragment implements ActionBar.TabListener{
//public MoviesFragment(){}
private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
private String[] tabs = { "InTheaters", "Upcoming", "Search" };
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_movies, container, false);
viewPager = (ViewPager)rootView.findViewById(R.id.pager);
actionBar = getActivity().getActionBar();
mAdapter = new TabsPagerAdapter(getActivity().getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name)
.setTabListener(this));
}
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// on changing the page
// make respected tab selected
actionBar.setSelectedNavigationItem(position);
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
});
return rootView;
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
}
问题是当我扩展片段活动时，它试图删除覆盖符号onCreate方法。没有它，我收到这个错误。有人可以告诉我一些解决方案吗？
这是完整的logcat：
06-11 00:23:57.196: E/AndroidRuntime(20226): FATAL EXCEPTION: main
06-11 00:23:57.196: E/AndroidRuntime(20226): java.lang.RuntimeException: Unable to start activity ComponentInfo{ashat.jaiswal.trr/ashat.jaiswal.trr.MainActivity}: java.lang.ClassCastException: ashat.jaiswal.trr.MainActivity cannot be cast to android.support.v4.app.FragmentActivity
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2306)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2358)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.ActivityThread.access$600(ActivityThread.java:156)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1340)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.os.Handler.dispatchMessage(Handler.java:99)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.os.Looper.loop(Looper.java:153)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.ActivityThread.main(ActivityThread.java:5297)
06-11 00:23:57.196: E/AndroidRuntime(20226): at java.lang.reflect.Method.invokeNative(Native Method)
06-11 00:23:57.196: E/AndroidRuntime(20226): at java.lang.reflect.Method.invoke(Method.java:511)
06-11 00:23:57.196: E/AndroidRuntime(20226): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
06-11 00:23:57.196: E/AndroidRuntime(20226): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
06-11 00:23:57.196: E/AndroidRuntime(20226): at dalvik.system.NativeStart.main(Native Method)
06-11 00:23:57.196: E/AndroidRuntime(20226): Caused by: java.lang.ClassCastException: ashat.jaiswal.trr.MainActivity cannot be cast to android.support.v4.app.FragmentActivity
06-11 00:23:57.196: E/AndroidRuntime(20226): at ashat.jaiswal.trr.MoviesFragment.onAttach(MoviesFragment.java:28)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:844)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1057)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.BackStackRecord.run(BackStackRecord.java:694)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.Activity.performStart(Activity.java:5131)
06-11 00:23:57.196: E/AndroidRuntime(20226): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2279)
06-11 00:23:57.196: E/AndroidRuntime(20226): ... 11 more
06-11 00:23:57.280: E/AppErrorDialog(498): Failed to get ILowStorageHandle instance
MainActivity.java
import java.util.ArrayList;
import android.app.Activity;
import android.app.Dialog;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.widget.DrawerLayout;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import ashat.jaiswal.trr.adapter.NavDrawerListAdapter;
import ashat.jaiswal.trr.model.NavDrawerItem;
public class MainActivity extends FragmentActivity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
// nav drawer title
private CharSequence mDrawerTitle;
// used to store app title
private CharSequence mTitle;
// slide menu items
private String[] navMenuTitles;
private TypedArray navMenuIcons;
private ArrayList<NavDrawerItem> navDrawerItems;
private NavDrawerListAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitle = mDrawerTitle = getTitle();
// load slide menu items
navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);
// nav drawer icons from resources
navMenuIcons = getResources()
.obtainTypedArray(R.array.nav_drawer_icons);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.list_slidermenu);
navDrawerItems = new ArrayList<NavDrawerItem>();
// adding nav drawer items to array
// Home
navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
// Find People
navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
// Photos
navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
// Communities, Will add a counter here
navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));
// Pages
navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
// What's hot, We will add a counter here
navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1)));
// Recycle the typed array
navMenuIcons.recycle();
mDrawerList.setOnItemClickListener(new SlideMenuClickListener());
// setting the nav drawer list adapter
adapter = new NavDrawerListAdapter(getApplicationContext(),
navDrawerItems);
mDrawerList.setAdapter(adapter);
// enabling action bar app icon and behaving it as toggle button
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.ic_drawer, //nav menu toggle icon
R.string.app_name, // nav drawer open - description for accessibility
R.string.app_name // nav drawer close - description for accessibility
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
// calling onPrepareOptionsMenu() to show action bar icons
invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
// calling onPrepareOptionsMenu() to hide action bar icons
invalidateOptionsMenu();
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
// on first time display view for first nav item
displayView(0);
}
}
/**
* Slide menu item click listener
* */
private class SlideMenuClickListener implements
ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// display view for selected nav drawer item
displayView(position);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
/**
* Diplaying fragment view for selected nav drawer list item
* */
private void displayView(int position) {
// update the main content by replacing fragments
Fragment fragment = null;
switch (position) {
==========================This part Shows errors===================================
case 0:
fragment = new MoviesFragment();
==========================This part Shows errors===================================
case 1:
fragment = new TVFragment();
break;
case 2:
fragment = new TheTopListFragment();
break;
case 3:
fragment = new ShareFragment();
break;
case 4:
fragment = new MoreFragment();
break;
case 5:
fragment = new AboutUsFragment();
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).commit();
// update selected item and title, then close the drawer
mDrawerList.setItemChecked(position, true);
mDrawerList.setSelection(position);
setTitle(navMenuTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
/**
* When using the ActionBarDrawerToggle, you must call it during
* onPostCreate() and onConfigurationChanged()...
*/
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Pass any configuration change to the drawer toggls
mDrawerToggle.onConfigurationChanged(newConfig);
}
}
答案 0 :(得分：0)
您的问题是您正在尝试将支持库与非支持库混合，这导致ClassCastExceptions。在这种情况下，当您可能需要android.support.v4.app.Fragment时，您正在使用android.app.Fragment。在MoviesFragment中，在导入语句中更改以下内容。
import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.FragmentTransaction;
import android.os.Bundle;
//import android.support.v4.app.Fragment;
import android.app.Fragment;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import ashat.jaiswal.trr.adapter.TabsPagerAdapter;
但是，如果您计划定位少于11的API版本，则需要重新编写大量代码。在这种情况下，您需要使用FragmentActivity代替Activity。