Java 如果我访问其他选项卡，水平回收视图将消失
在我的android项目中，主页上有三个选项卡。我将水平回收视图放在第三个选项卡中。它第一次运行良好，但当我访问第一个选项卡并返回时，水平回收视图消失了。谁来帮帮我 代码如下所示 Tab3.xmlJava 如果我访问其他选项卡，水平回收视图将消失,java,android,xml,Java,Android,Xml,在我的android项目中，主页上有三个选项卡。我将水平回收视图放在第三个选项卡中。它第一次运行良好，但当我访问第一个选项卡并返回时，水平回收视图消失了。谁来帮帮我 代码如下所示 Tab3.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="matc
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
>
<TextView
android:id="@+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Suggestions" />
<FrameLayout
android:id="@+id/fragmentContainer"
android:layout_width="match_parent"
android:layout_height="180dp"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical" />
</LinearLayout>
</LinearLayout>
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener,TabLayout.OnTabSelectedListener {
private TabLayout tabLayout;
private ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
tabLayout = (TabLayout) findViewById(R.id.tabLayout);
//Adding the tabs using addTab() method
tabLayout.addTab(tabLayout.newTab().setText("Home"));
tabLayout.addTab(tabLayout.newTab().setText("Favourites"));
tabLayout.addTab(tabLayout.newTab().setText("Trending"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
//Initializing viewPager
viewPager = (ViewPager) findViewById(R.id.pager);
//Creating our pager adapter
Pager adapter = new Pager(getSupportFragmentManager(), tabLayout.getTabCount());
//Adding adapter to pager
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
//Adding onTabSelectedListener to swipe views
tabLayout.setOnTabSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@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 boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
}
我认为你的片段不是空的：
Fragment fragment = fm.findFragmentById(R.id.fragmentContainer);
if (fragment == null) {
fragment = new HorizontalListViewFragment();
;
fm.beginTransaction()
.add(R.id.fragmentContainer, fragment)
.commit();
}
谢谢你的回复，有什么解决办法吗？我应该把它变成！=而不是==？我认为你不需要检查片段是否为空，因为你需要创建一个片段并将其添加到你的视图中哦，它起作用了！当我删除那个if条件时，这个问题就解决了，但现在它在这里显示了一个警告-Fragment Fragment=fm.findffragmentbyid（R.id.fragmentContainer）；您是否使用ViewPager adapter显示选项卡？是的，我正在使用ViewPager adapter，是否应在添加选项卡的位置添加MainActivity代码？您是否可以发布ViewPager适配器代码？我已添加了编写ViewPager适配器代码的MainActivity.java代码，请检查是否与getSupportFragmentManager（）有关和getFragmentManager（）？因为我在MainActivity中使用了getSupportFragmentManager（），在Tab3.java中使用了getFragmentManager（）
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Arshad on 09-06-2017.
*/
public class Tab3 extends Fragment {
ListView listView;
listItemAdapterPop listItemAdapter_Pop;
String[] names = {"Hrithik","Ranbir","AkshayKumar","Amir Khan","Shahidi Kapoor"};
String[] type = {"Bollywood actor","Mollywood Actor","Dancer","Playback Singer","DJ"};
int[] images = {R.drawable.index1,R.drawable.index2,R.drawable.index3,R.drawable.index4,R.drawable.index5};
private List<Artists> artistList = new ArrayList<>();
private RecyclerView recyclerView;
private ArtistAdapter mAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.tab3,container,false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// listView = (ListView)view.findViewById(R.id.listView_pop);
// listItemAdapter_Pop = new listItemAdapterPop(getActivity(),names,images,type);
// listView.setAdapter(listItemAdapter_Pop);
//listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
// @Override
//public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
// Toast.makeText(getActivity(), "you can view the profile of :"+names[i], Toast.LENGTH_SHORT).show();
// }
//});
FragmentManager fm = getFragmentManager();
Fragment fragment = fm.findFragmentById(R.id.fragmentContainer);
if (fragment == null) {
fragment = new HorizontalListViewFragment();
;
fm.beginTransaction()
.add(R.id.fragmentContainer, fragment)
.commit();
}
recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
mAdapter = new ArtistAdapter(artistList);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), LinearLayoutManager.VERTICAL));
// set the adapter
recyclerView.setAdapter(mAdapter);
prepareArtistData();
recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity(), recyclerView, new RecyclerTouchListener.ClickListener() {
@Override
public void onClick(View view, int position) {
Artists artist = artistList.get(position);
Toast.makeText(getActivity(), artist.getArtistName() + " is selected!", Toast.LENGTH_SHORT).show();
}
@Override
public void onLongClick(View view, int position) {
Artists artist = artistList.get(position);
Toast.makeText(getActivity(), artist.getArtistName() + " is long pressed selected!", Toast.LENGTH_SHORT).show();
}
}));
}
public void prepareArtistData(){
for(int i=0;i<names.length;i++){
Artists artist = new Artists(names[i], type[i], images[i]);
artistList.add(artist);
}
mAdapter.notifyDataSetChanged();
}
}
package com.example.majedhussain.loginsample;
/**
* Created by anonymous on 11/4/16.
*/
import android.content.ContentResolver;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class HorizontalListViewFragment extends Fragment {
ArrayList<Artists> listitems = new ArrayList<>();
RecyclerView MyRecyclerView;
String ArtistsS[] = {"Hrithik","Ranbir","AkshayKumar","Amir Khan","Shahidi Kapoor"};
int Images[] = {R.drawable.index1,R.drawable.index2,R.drawable.index3,R.drawable.index4,R.drawable.index5};
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
listitems.clear();
for(int i =0;i<ArtistsS.length;i++){
Artists item = new Artists();
item.setArtistName(ArtistsS[i]);
item.setImageResourceId(Images[i]);
item.setIsfav(0);
item.setIsturned(0);
listitems.add(item);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_horizontal_list_view, container, false);
MyRecyclerView = (RecyclerView) view.findViewById(R.id.cardView);
MyRecyclerView.setHasFixedSize(true);
LinearLayoutManager MyLayoutManager = new LinearLayoutManager(getActivity());
MyLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
if (listitems.size() > 0 & MyRecyclerView != null) {
MyRecyclerView.setAdapter(new MyAdapter(listitems));
}
MyRecyclerView.setLayoutManager(MyLayoutManager);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {
private ArrayList<Artists> list;
public MyAdapter(ArrayList<Artists> Data) {
list = Data;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recycle_items, parent, false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(final MyViewHolder holder, int position) {
holder.titleTextView.setText(list.get(position).getArtistName());
holder.coverImageView.setImageResource(list.get(position).getImageResourceId());
holder.coverImageView.setTag(list.get(position).getImageResourceId());
holder.likeImageView.setTag(R.drawable.ic_like);
}
@Override
public int getItemCount() {
return list.size();
}
}
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView titleTextView;
public ImageView coverImageView;
public ImageView likeImageView;
public ImageView shareImageView;
public MyViewHolder(View v) {
super(v);
titleTextView = (TextView) v.findViewById(R.id.titleTextView);
coverImageView = (ImageView) v.findViewById(R.id.coverImageView);
likeImageView = (ImageView) v.findViewById(R.id.likeImageView);
shareImageView = (ImageView) v.findViewById(R.id.shareImageView);
likeImageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int id = (int)likeImageView.getTag();
if( id == R.drawable.ic_like){
likeImageView.setTag(R.drawable.ic_liked);
likeImageView.setImageResource(R.drawable.ic_liked);
Toast.makeText(getActivity(),titleTextView.getText()+" added to favourites", Toast.LENGTH_SHORT).show();
}else{
likeImageView.setTag(R.drawable.ic_like);
likeImageView.setImageResource(R.drawable.ic_like);
Toast.makeText(getActivity(),titleTextView.getText()+" removed from favourites", Toast.LENGTH_SHORT).show();
}
}
});
shareImageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Uri imageUri = Uri.parse(ContentResolver.SCHEME_ANDROID_RESOURCE +
"://" + getResources().getResourcePackageName(coverImageView.getId())
+ '/' + "drawable" + '/' + getResources().getResourceEntryName((int)coverImageView.getTag()));
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND);
shareIntent.putExtra(Intent.EXTRA_STREAM,imageUri);
shareIntent.setType("image/jpeg");
startActivity(Intent.createChooser(shareIntent, getResources().getText(R.string.send_to)));
}
});
}
}
}
package com.example.majedhussain.loginsample;
/**
* Created by MAJED HUSSAIN on 14-06-2017.
*/
public class Artists {
String artistName;
String desc;
int imageResourceId;
int isfav;
int isturned;
public Artists(String artistName, String desc, int imageResourceId) {
this.artistName = artistName;
this.desc = desc;
this.imageResourceId = imageResourceId;
}
public Artists() {
}
public void setDesc(String desc){
this.desc = desc;
}
public String getDesc() {
return desc;
}
public int getIsturned() {
return isturned;
}
public void setIsturned(int isturned) {
this.isturned = isturned;
}
public int getIsfav() {
return isfav;
}
public void setIsfav(int isfav) {
this.isfav = isfav;
}
public String getArtistName() {
return artistName;
}
public void setArtistName(String artistName) {
this.artistName = artistName;
}
public int getImageResourceId() {
return imageResourceId;
}
public void setImageResourceId(int imageResourceId) {
this.imageResourceId = imageResourceId;
}
}
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener,TabLayout.OnTabSelectedListener {
private TabLayout tabLayout;
private ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
tabLayout = (TabLayout) findViewById(R.id.tabLayout);
//Adding the tabs using addTab() method
tabLayout.addTab(tabLayout.newTab().setText("Home"));
tabLayout.addTab(tabLayout.newTab().setText("Favourites"));
tabLayout.addTab(tabLayout.newTab().setText("Trending"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
//Initializing viewPager
viewPager = (ViewPager) findViewById(R.id.pager);
//Creating our pager adapter
Pager adapter = new Pager(getSupportFragmentManager(), tabLayout.getTabCount());
//Adding adapter to pager
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
//Adding onTabSelectedListener to swipe views
tabLayout.setOnTabSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@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 boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
}
Fragment fragment = fm.findFragmentById(R.id.fragmentContainer);
if (fragment == null) {
fragment = new HorizontalListViewFragment();
;
fm.beginTransaction()
.add(R.id.fragmentContainer, fragment)
.commit();
}