片段和ListFragment不兼容 [英] Fragment and ListFragment incompatibility
本文介绍了片段和ListFragment不兼容的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有这样的方法启动，当我从菜单中选择一个页面。问题是，其中的一些扩展片段就像从案例1到6，而其他延长 ListFragment 在情况7
我得到一个：类型不匹配：不能从ItemListFragment转换成片段错误
我要如何解决这个问题？
包com.prjma.lovertech.activity;
进口的java.util.ArrayList;
进口android.app.Activity;
进口android.content.res.Configuration;
进口android.content.res.TypedArray;
进口android.os.Bundle;
进口android.support.v4.app.ActionBarDrawerToggle;
进口android.support.v4.app.ListFragment;
//进口android.app.ListFragment;
进口android.app.Fragment;
进口android.app.FragmentManager;
进口android.app.FragmentTransaction;
进口android.support.v4.widget.DrawerLayout;
进口android.util.Log;
进口android.view.Menu;
进口android.view.MenuItem;
进口android.view.View;
进口android.widget.AdapterView;
进口android.widget.ListView;
进口com.prjma.lovertech.R;
进口com.prjma.lovertech.R.array;
进口com.prjma.lovertech.R.drawable;
进口com.prjma.lovertech.R.id;
进口com.prjma.lovertech.R.layout;
进口com.prjma.lovertech.R.menu;
进口com.prjma.lovertech.R.string;
进口com.prjma.lovertech.adapter.NavDrawerListAdapter;
进口com.prjma.lovertech.fragment *。
进口com.prjma.lovertech.model.NavDrawerItem;
进口com.prjma.lovertech.util.SessionManager;
公共类WallActivity延伸活动{
私人DrawerLayout mDrawerLayout;
私人的ListView mDrawerList;
私人ActionBarDrawerToggle mDrawerToggle;
//导航抽屉称号
私人的CharSequence mDrawerTitle;
//用于存储应用程序标题
私人的CharSequence mTitle;
//滑动菜单项
私有String [] navMenuTitles;
私人TypedArray navMenuIcons;
私人的ArrayList＆LT; NavDrawerItem＆GT; navDrawerItems;
私人NavDrawerListAdapter适配器;
//会话管理器类
公众是SessionManager会议;
@覆盖
保护无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
的setContentView（R.layout.activity_wall）;
//会话管理器
会议=新SessionManager（中间getApplicationContext（））;
/ **
*每当你要检查用户登录调用此函数
*这将用户重定向到LoginActivity是，他是不是
* 登录
* * /
session.checkLogin（）;
mTitle = mDrawerTitle =的getTitle（）;
//负荷滑动菜单项
navMenuTitles = getResources（）getStringArray（R.array.nav_drawer_items）。
//导航抽屉，从资源的图标
navMenuIcons = getResources（）
.obtainTypedArray（R.array.nav_drawer_icons）;
mDrawerLayout =（DrawerLayout）findViewById（R.id.drawer_layout）;
mDrawerList =（ListView控件）findViewById（R.id.list_slidermenu）;
navDrawerItems =新的ArrayList＆LT; NavDrawerItem＆GT;（）;
//添加导航抽屉里的物品数组
// 家
navDrawerItems.add（新NavDrawerItem（navMenuTitles [0]，navMenuIcons.getResourceId（0，-1）））;
// Messaggi
navDrawerItems.add（新NavDrawerItem（navMenuTitles [1]，navMenuIcons.getResourceId（1，-1）））;
// Oggettti seguiti
navDrawerItems.add（新NavDrawerItem（navMenuTitles [2]，navMenuIcons.getResourceId（2，-1）））;
// Oggetti acquistati，将在这里添加计数器
navDrawerItems.add（新NavDrawerItem（navMenuTitles [3]，navMenuIcons.getResourceId（3，-1），真，22））;
//在vendita
navDrawerItems.add（新NavDrawerItem（navMenuTitles [4]，navMenuIcons.getResourceId（4，-1）））;
// Venduti
navDrawerItems.add（新NavDrawerItem（navMenuTitles [5]，navMenuIcons.getResourceId（5，-1），真正的50+））;
// Invenduti
navDrawerItems.add（新NavDrawerItem（navMenuTitles [6]，navMenuIcons.getResourceId（6，-1），真，3））;
// 列表显示
navDrawerItems.add（新NavDrawerItem（navMenuTitles [7]，navMenuIcons.getResourceId（7，-1）））;
//回收类型数组
navMenuIcons.recycle（）;
mDrawerList.setOnItemClickListener（新SlideMenuClickListener（））;
//设置导航抽屉名单适配器
适配器=新NavDrawerListAdapter（getApplicationContext（）
navDrawerItems）;
mDrawerList.setAdapter（适配器）;
//使操作栏中的应用程序图标，它表现为切换按钮
getActionBar（）setDisplayHomeAsUpEnabled（真）。
getActionBar（）setHomeButtonEnabled（真）。
mDrawerToggle =新ActionBarDrawerToggle（这一点，mDrawerLayout，
R.drawable.ic_drawer，//导航菜单切换图标
R.string.app_name，//导航抽屉打开 - 说明访问
R.string.app_name //导航抽屉关闭 - 说明访问
）{
公共无效onDrawerClosed（查看视图）{
。getActionBar（）的setTitle（mTitle）;
//调用prepareOptionsMenu（）来显示操作栏图标
invalidateOptionsMenu（）;
}
公共无效onDrawerOpened（查看drawerView）{
。getActionBar（）的setTitle（mDrawerTitle）;
//调用prepareOptionsMenu（）隐藏操作栏图标
invalidateOptionsMenu（）;
}
};
mDrawerLayout.setDrawerListener（mDrawerToggle）;
如果（savedInstanceState == NULL）{
//关于第一导航项目首次显示视图
displayView（0）;
}
}
/ **
*滑动菜单项，点击监听器
* * /
私有类SlideMenuClickListener工具
ListView.OnItemClickListener {
@覆盖
公共无效onItemClick（适配器视图＆LT;＆GT;母公司视图中查看，INT位置，
长ID）{
对选定的导航抽屉的项目//显示视图
displayView（位置）;
}
}
@覆盖
公共布尔onCreateOptionsMenu（功能菜单）{
。getMenuInflater（）膨胀（R.menu.menu，菜单）;
返回true;
}
→
包com.prjma.lovertech.fragment;
进口com.prjma.lovertech.R;
进口android.app.Fragment;
进口android.os.Bundle;
进口android.view.LayoutInflater;
进口android.view.View;
进口android.view.ViewGroup;
公共类InvendutiFragment扩展片段{
公共InvendutiFragment（）{}
@覆盖
公共查看onCreateView（LayoutInflater充气，容器的ViewGroup，
捆绑savedInstanceState）{
查看rootView = inflater.inflate（R.layout.fragment_invenduti，集装箱，假）;
返回rootView;
}
}
LL
包com.prjma.lovertech.fragment;
进口android.app.Activity;
进口android.os.Bundle;
进口android.support.v4.app.ListFragment;
进口android.view.View;
进口android.widget.AbsListView;
进口android.widget.AdapterView;
进口android.widget.ArrayAdapter;
进口android.widget.ListView;
进口com.prjma.lovertech.dummy.DummyContent;
/ **
*列表片段重新presenting项目的列表。这个片段也支持
*通过允许列表项平板设备被赋予在一个激活状态
*选择。这有助于指示哪个项目当前正在查看的
* {@link ItemDetailFragment}。
*所述p为H.;
*含该片段活动必须贯彻{@link回调}
* 接口。
* /
公共类ItemListFragment扩展ListFragment {
/ **
*序列化（保存实例状态）软件包密钥再presenting的
*启动项的位置。仅用于平板电脑。
* /
私有静态最后弦乐STATE_ACTIVATED_POSITION =activated_position;
/ **
*片段的当前回调对象，它被通知的列表项的
*点击。
* /
私人回调mCallbacks = sDummyCallbacks;
/ **
*当前激活项目的位置。仅用于平板电脑。
* /
私人诠释mActivatedPosition = ListView.INVALID_POSITION;
/ **
*含有该片段的所有活动的回调接口必须
* 实现。此机制允许项目的活动，以通知
*选择。
* /
公共接口回调{
/ **
*回调时，项目已被选定为。
* /
公共无效onItemSelected（字符串ID）;
}
/ **
*一个虚拟实现，它的{@link回调}接口
*什么都没有。时才使用该片段没有连接到活动。
* /
私有静态回调sDummyCallbacks =新的回调（）{
@覆盖
公共无效onItemSelected（字符串ID）{
}
};
/ **
*必须填写空的构造的片段经理来实例化
*片段（如在屏幕方向变化）。
* /
公共ItemListFragment（）{
}
@覆盖
公共无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
// TODO：换成一个真正的名单适配器。
setListAdapter（新ArrayAdapter＆其中; DummyContent.DummyItem＆GT;（getActivity（），
android.R.layout.simple_list_item_activated_1，
android.R.id.text1，DummyContent.ITEMS））;
}
@覆盖
公共无效onViewCreated（查看视图，捆绑savedInstanceState）{
super.onViewCreated（查看，savedInstanceState）;
//恢复previously连载启动项的位置。
如果（savedInstanceState！= NULL
＆功放;＆安培; savedInstanceState.containsKey（STATE_ACTIVATED_POSITION））{
setActivatedPosition（savedInstanceState
.getInt（STATE_ACTIVATED_POSITION））;
}
}
@覆盖
公共无效onAttach（活动活动）{
super.onAttach（活动）;
//活动包含该片段必须实现回调。
如果（！（活动的instanceof回调））{
抛出新IllegalStateException异常（
活动必须实现片段的回调。）;
}
mCallbacks =（回调）的活动;
}
@覆盖
公共无效onDetach（）{
super.onDetach（）;
//重置活性回调接口到哑实施。
mCallbacks = sDummyCallbacks;
}
@覆盖
公共无效onListItemClick（ListView控件的ListView，视图中查看，INT位置，
长ID）{
super.onListItemClick（ListView控件，观点，立场，身份证）;
//通知活性回调接口（活性，如果
//片段连接到一个），该项目已经被选择。
mCallbacks.onItemSelected（DummyContent.ITEMS.get（位置）.ID）;
}
@覆盖
公共无效的onSaveInstanceState（包outState）{
super.onSaveInstanceState（outState）;
如果（mActivatedPosition！= AdapterView.INVALID_POSITION）{
//序列化和持久化启动项目的位置。
outState.putInt（STATE_ACTIVATED_POSITION，mActivatedPosition）;
}
}
/ **
*启用激活上点击模式。当该模式上，列表项将是
*给出的激活状态，触摸时。
* /
公共无效setActivateOnItemClick（布尔activateOnItemClick）{
//当设置CHOICE_MODE_SINGLE，ListView控件会自动
触摸时//给项目的激活状态。
getListView（）。setChoiceMode（
activateOnItemClick？ AbsListView.CHOICE_MODE_SINGLE
：AbsListView.CHOICE_MODE_NONE）;
}
私人无效setActivatedPosition（INT位置）{
如果（位置== AdapterView.INVALID_POSITION）{
getListView（）setItemChecked（mActivatedPosition，假）。
} 其他 {
getListView（）setItemChecked（位置，真正的）。
}
mActivatedPosition =位置;
}
}
解决方案
我会做这种方式：
私人无效displayView（INT位置）{
//更新替换片段的主要内容
片段片段= NULL;
ListFragment listfragment = NULL;
开关（位置）{
情况下0：
片段=新HomeFragment（）;
打破;
情况1：
片段=新MessaggiFragment（）;
打破;
案例2：
片段=新OggettiSeguitiFragment（）;
打破;
案例3：
片段=新OggettiAcquistatiFragment（）;
打破;
壳体4：
片段=新InVenditaFragment（）;
打破;
壳体5：
片段=新VendutiFragment（）;
打破;
情况6：
片段=新InvendutiFragment（）;
打破;
案例7：
listfragment =新ItemListFragment（）;
打破;
默认：
打破;
}
如果（片段！= NULL）{
//做的东西，如果它是一个片段
FragmentManager fragmentManager = getFragmentManager（）;
fragmentManager.beginTransaction（）
.replace（R.id.frame_container，片段）.commit（）;
}否则，如果（listfragment！= NULL）{
//做的东西，如果它是一个listfragment
FragmentManager fragmentManager = getFragmentManager（）;
fragmentManager.beginTransaction（）
.replace（R.id.frame_container，listfragment）.commit（）;
} 其他 {
//创建片段错误
Log.e（MainActivity，创建片段错误）;
}
I have this method that launches a page when I select it from a menu. The problem is that some of these extend Fragment like from case 1 to 6, while others extend ListFragment as in case 7.
I get a: Type mismatch: cannot convert from ItemListFragment to Fragment error.
How do I solve this?
package com.prjma.lovertech.activity;
import java.util.ArrayList;
import android.app.Activity;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.ListFragment;
//import android.app.ListFragment;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import com.prjma.lovertech.R;
import com.prjma.lovertech.R.array;
import com.prjma.lovertech.R.drawable;
import com.prjma.lovertech.R.id;
import com.prjma.lovertech.R.layout;
import com.prjma.lovertech.R.menu;
import com.prjma.lovertech.R.string;
import com.prjma.lovertech.adapter.NavDrawerListAdapter;
import com.prjma.lovertech.fragment.*;
import com.prjma.lovertech.model.NavDrawerItem;
import com.prjma.lovertech.util.SessionManager;
public class WallActivity extends Activity {
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;
// Session Manager Class
public SessionManager session;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_wall);
// Session Manager
session = new SessionManager(getApplicationContext());
/**
* Call this function whenever you want to check user login
* This will redirect user to LoginActivity is he is not
* logged in
* */
session.checkLogin();
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)));
// Messaggi
navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
// Oggettti seguiti
navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
// Oggetti acquistati, Will add a counter here
navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1), true, "22"));
// In vendita
navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
// Venduti
navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1), true, "50+"));
// Invenduti
navDrawerItems.add(new NavDrawerItem(navMenuTitles[6], navMenuIcons.getResourceId(6, -1), true, "3"));
// ListView
navDrawerItems.add(new NavDrawerItem(navMenuTitles[7], navMenuIcons.getResourceId(7, -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.menu, menu);
return true;
}
l
package com.prjma.lovertech.fragment;
import com.prjma.lovertech.R;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class InvendutiFragment extends Fragment {
public InvendutiFragment(){}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_invenduti, container, false);
return rootView;
}
}
ll
package com.prjma.lovertech.fragment;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import com.prjma.lovertech.dummy.DummyContent;
/**
* A list fragment representing a list of Items. This fragment also supports
* tablet devices by allowing list items to be given an 'activated' state upon
* selection. This helps indicate which item is currently being viewed in a
* {@link ItemDetailFragment}.
* <p>
* Activities containing this fragment MUST implement the {@link Callbacks}
* interface.
*/
public class ItemListFragment extends ListFragment {
/**
* The serialization (saved instance state) Bundle key representing the
* activated item position. Only used on tablets.
*/
private static final String STATE_ACTIVATED_POSITION = "activated_position";
/**
* The fragment's current callback object, which is notified of list item
* clicks.
*/
private Callbacks mCallbacks = sDummyCallbacks;
/**
* The current activated item position. Only used on tablets.
*/
private int mActivatedPosition = ListView.INVALID_POSITION;
/**
* A callback interface that all activities containing this fragment must
* implement. This mechanism allows activities to be notified of item
* selections.
*/
public interface Callbacks {
/**
* Callback for when an item has been selected.
*/
public void onItemSelected(String id);
}
/**
* A dummy implementation of the {@link Callbacks} interface that does
* nothing. Used only when this fragment is not attached to an activity.
*/
private static Callbacks sDummyCallbacks = new Callbacks() {
@Override
public void onItemSelected(String id) {
}
};
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public ItemListFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// TODO: replace with a real list adapter.
setListAdapter(new ArrayAdapter<DummyContent.DummyItem>(getActivity(),
android.R.layout.simple_list_item_activated_1,
android.R.id.text1, DummyContent.ITEMS));
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Restore the previously serialized activated item position.
if (savedInstanceState != null
&& savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
setActivatedPosition(savedInstanceState
.getInt(STATE_ACTIVATED_POSITION));
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// Activities containing this fragment must implement its callbacks.
if (!(activity instanceof Callbacks)) {
throw new IllegalStateException(
"Activity must implement fragment's callbacks.");
}
mCallbacks = (Callbacks) activity;
}
@Override
public void onDetach() {
super.onDetach();
// Reset the active callbacks interface to the dummy implementation.
mCallbacks = sDummyCallbacks;
}
@Override
public void onListItemClick(ListView listView, View view, int position,
long id) {
super.onListItemClick(listView, view, position, id);
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mCallbacks.onItemSelected(DummyContent.ITEMS.get(position).id);
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (mActivatedPosition != AdapterView.INVALID_POSITION) {
// Serialize and persist the activated item position.
outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
}
}
/**
* Turns on activate-on-click mode. When this mode is on, list items will be
* given the 'activated' state when touched.
*/
public void setActivateOnItemClick(boolean activateOnItemClick) {
// When setting CHOICE_MODE_SINGLE, ListView will automatically
// give items the 'activated' state when touched.
getListView().setChoiceMode(
activateOnItemClick ? AbsListView.CHOICE_MODE_SINGLE
: AbsListView.CHOICE_MODE_NONE);
}
private void setActivatedPosition(int position) {
if (position == AdapterView.INVALID_POSITION) {
getListView().setItemChecked(mActivatedPosition, false);
} else {
getListView().setItemChecked(position, true);
}
mActivatedPosition = position;
}
}
解决方案
I would do it this way:
private void displayView(int position) {
// update the main content by replacing fragments
Fragment fragment = null;
ListFragment listfragment = null;
switch (position) {
case 0:
fragment = new HomeFragment();
break;
case 1:
fragment = new MessaggiFragment();
break;
case 2:
fragment = new OggettiSeguitiFragment();
break;
case 3:
fragment = new OggettiAcquistatiFragment();
break;
case 4:
fragment = new InVenditaFragment();
break;
case 5:
fragment = new VendutiFragment();
break;
case 6:
fragment = new InvendutiFragment();
break;
case 7:
listfragment = new ItemListFragment();
break;
default:
break;
}
if (fragment != null) {
// do stuff if it's a fragment
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).commit();
} else if (listfragment != null) {
// do stuff if its a listfragment
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, listfragment).commit();
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
这篇关于片段和ListFragment不兼容的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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