viewpagerに動的にビューを追加および削除する
（私は解決策を考え出しました - 下のAnswerセクションで私の投稿を見てください。
私のアプリでは、ユーザーは自分のデータの単一のビューから始めます。 ViewPagerを追加して、ユーザーが必要に応じてビューを追加できるようにします。どうやってこれをするの？ （FragmentPagerAdapterは使いたくありません。）
私は数え切れないほどの投稿や概要を読んでいますが、まだ何かが足りないのです。これが私が理解していることです。
MainActivityはViewPagerとPagerAdapterを作成します。
ViewPager pager = null;
MainPagerAdapter adapter = null;
public void onCreate (Bundle savedInstanceState)
{
super.onCreate (savedInstanceState);
pager = new ViewPager (this);
setContentView (pager);
adapter = new MainPagerAdapter();
pager.setAdapter (adapter);
View v0 = code_to_create_initial_view();
adapter.add (v0, 0);
}
PagerAdapterを使用して一連のビューを提供します。そのためには、ビューを追加したり削除したりするためのメソッドが必要です。 ViewPagerのものが変更されたこと、およびその変更をどのように表示するかを指示するには、明らかにより多くのものが必要です。
class MainPagerAdapter extends PagerAdapter
{
// This holds all the currently displayable views, in order from left to right.
private ArrayList<View> views = new ArrayList<View>();
public void addView (View v, int position)
{
views.add (position, v);
}
public void removeView (int position)
{
views.remove (position);
}
}
さらに、私は以下の重要な方法を実行する必要があります。私はここで道に迷っています - 何が彼らを呼んでいますか？
public object instantiateItem (ViewGroup pager, int position);
public void destroyItem (ViewGroup, int, Object);
public int getCount ();
public boolean isViewFromObject (View, Object);
- ViewGroupパラメータは何のためにあるのですか - ViewPager自体を含んでいるグループではありませんか？
- IsViewFromObjectとは何ですか？ - オブジェクトは最初にビューとどのように関連付けられますか？
- ビューを追加または削除するときにstartUpdateとfinishUdateを呼び出す必要がありますか？
ありがとう。
どのViewPagerメソッドがViewPagerによって呼び出され、どのViewPagerメソッドが他の目的のためにあるのかを理解した後、私は解決策を思い付きました。私は多くの人がこれに苦しんでいるのを見たので私はここでそれを提示します、そして私は他の関連する答えを見ませんでした。
まず、これが私のアダプタです。うまくいけば、コード内のコメントで十分です。
public class MainPagerAdapter extends PagerAdapter
{
// This holds all the currently displayable views, in order from left to right.
private ArrayList<View> views = new ArrayList<View>();
//-----------------------------------------------------------------------------
// Used by ViewPager. "Object" represents the page; tell the ViewPager where the
// page should be displayed, from left-to-right. If the page no longer exists,
// return POSITION_NONE.
@Override
public int getItemPosition (Object object)
{
int index = views.indexOf (object);
if (index == -1)
return POSITION_NONE;
else
return index;
}
//-----------------------------------------------------------------------------
// Used by ViewPager. Called when ViewPager needs a page to display; it is our job
// to add the page to the container, which is normally the ViewPager itself. Since
// all our pages are persistent, we simply retrieve it from our "views" ArrayList.
@Override
public Object instantiateItem (ViewGroup container, int position)
{
View v = views.get (position);
container.addView (v);
return v;
}
//-----------------------------------------------------------------------------
// Used by ViewPager. Called when ViewPager no longer needs a page to display; it
// is our job to remove the page from the container, which is normally the
// ViewPager itself. Since all our pages are persistent, we do nothing to the
// contents of our "views" ArrayList.
@Override
public void destroyItem (ViewGroup container, int position, Object object)
{
container.removeView (views.get (position));
}
//-----------------------------------------------------------------------------
// Used by ViewPager; can be used by app as well.
// Returns the total number of pages that the ViewPage can display. This must
// never be 0.
@Override
public int getCount ()
{
return views.size();
}
//-----------------------------------------------------------------------------
// Used by ViewPager.
@Override
public boolean isViewFromObject (View view, Object object)
{
return view == object;
}
//-----------------------------------------------------------------------------
// Add "view" to right end of "views".
// Returns the position of the new view.
// The app should call this to add pages; not used by ViewPager.
public int addView (View v)
{
return addView (v, views.size());
}
//-----------------------------------------------------------------------------
// Add "view" at "position" to "views".
// Returns position of new view.
// The app should call this to add pages; not used by ViewPager.
public int addView (View v, int position)
{
views.add (position, v);
return position;
}
//-----------------------------------------------------------------------------
// Removes "view" from "views".
// Retuns position of removed view.
// The app should call this to remove pages; not used by ViewPager.
public int removeView (ViewPager pager, View v)
{
return removeView (pager, views.indexOf (v));
}
//-----------------------------------------------------------------------------
// Removes the "view" at "position" from "views".
// Retuns position of removed view.
// The app should call this to remove pages; not used by ViewPager.
public int removeView (ViewPager pager, int position)
{
// ViewPager doesn't have a delete method; the closest is to set the adapter
// again. When doing so, it deletes all its views. Then we can delete the view
// from from the adapter and finally set the adapter to the pager again. Note
// that we set the adapter to null before removing the view from "views" - that's
// because while ViewPager deletes all its views, it will call destroyItem which
// will in turn cause a null pointer ref.
pager.setAdapter (null);
views.remove (position);
pager.setAdapter (this);
return position;
}
//-----------------------------------------------------------------------------
// Returns the "view" at "position".
// The app should call this to retrieve a view; not used by ViewPager.
public View getView (int position)
{
return views.get (position);
}
// Other relevant methods:
// finishUpdate - called by the ViewPager - we don't care about what pages the
// pager is displaying so we don't use this method.
}
そして、これはアダプタの使い方を示すコードの断片です。
class MainActivity extends Activity
{
private ViewPager pager = null;
private MainPagerAdapter pagerAdapter = null;
//-----------------------------------------------------------------------------
@Override
public void onCreate (Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView (R.layout.main_activity);
... do other initialization, such as create an ActionBar ...
pagerAdapter = new MainPagerAdapter();
pager = (ViewPager) findViewById (R.id.view_pager);
pager.setAdapter (pagerAdapter);
// Create an initial view to display; must be a subclass of FrameLayout.
LayoutInflater inflater = context.getLayoutInflater();
FrameLayout v0 = (FrameLayout) inflater.inflate (R.layout.one_of_my_page_layouts, null);
pagerAdapter.addView (v0, 0);
pagerAdapter.notifyDataSetChanged();
}
//-----------------------------------------------------------------------------
// Here's what the app should do to add a view to the ViewPager.
public void addView (View newPage)
{
int pageIndex = pagerAdapter.addView (newPage);
// You might want to make "newPage" the currently displayed page:
pager.setCurrentItem (pageIndex, true);
}
//-----------------------------------------------------------------------------
// Here's what the app should do to remove a view from the ViewPager.
public void removeView (View defunctPage)
{
int pageIndex = pagerAdapter.removeView (pager, defunctPage);
// You might want to choose what page to display, if the current page was "defunctPage".
if (pageIndex == pagerAdapter.getCount())
pageIndex--;
pager.setCurrentItem (pageIndex);
}
//-----------------------------------------------------------------------------
// Here's what the app should do to get the currently displayed page.
public View getCurrentPage ()
{
return pagerAdapter.getView (pager.getCurrentItem());
}
//-----------------------------------------------------------------------------
// Here's what the app should do to set the currently displayed page. "pageToShow" must
// currently be in the adapter, or this will crash.
public void setCurrentPage (View pageToShow)
{
pager.setCurrentItem (pagerAdapter.getItemPosition (pageToShow), true);
}
}
最後に、あなたはあなたのactivity_main.xmlレイアウトのために以下を使うことができます：
<?xml version="1.0" encoding="utf-8"?>
<Android.support.v4.view.ViewPager
xmlns:Android="http://schemas.Android.com/apk/res/Android"
Android:id="@+id/view_pager"
Android:layout_width="match_parent"
Android:layout_height="match_parent" >
</Android.support.v4.view.ViewPager>
私はviewpagerからビューを動的に削除する簡単な解決策を探していました。そのため、自分のページが属する情報がある場合は、それを[タグとして表示]に設定できます。ちょうどそのような（アダプタコード）：
@Override
public Object instantiateItem(ViewGroup collection, int position)
{
ImageView iv = new ImageView(mContext);
MediaMessage msg = mMessages.get(position);
...
iv.setTag(media);
return iv;
}
@Override
public int getItemPosition (Object object)
{
View o = (View) object;
int index = mMessages.indexOf(o.getTag());
if (index == -1)
return POSITION_NONE;
else
return index;
}
MMessagesから自分の情報を削除して、アダプタ用にnotifyDataSetChanged()を呼び出すだけです。悪いニュースですが、この場合はアニメーションはありません。
これはこの質問に対する代替解決策です。私のアダプター：
private class PagerAdapter extends FragmentPagerAdapter implements
ViewPager.OnPageChangeListener, TabListener {
private List<Fragment> mFragments = new ArrayList<Fragment>();
private ViewPager mPager;
private ActionBar mActionBar;
private Fragment mPrimaryItem;
public PagerAdapter(FragmentManager fm, ViewPager vp, ActionBar ab) {
super(fm);
mPager = vp;
mPager.setAdapter(this);
mPager.setOnPageChangeListener(this);
mActionBar = ab;
}
public void addTab(PartListFragment frag) {
mFragments.add(frag);
mActionBar.addTab(mActionBar.newTab().setTabListener(this).
setText(frag.getPartCategory()));
}
@Override
public Fragment getItem(int position) {
return mFragments.get(position);
}
@Override
public int getCount() {
return mFragments.size();
}
/** (non-Javadoc)
* @see Android.support.v4.app.FragmentStatePagerAdapter#setPrimaryItem(Android.view.ViewGroup, int, Java.lang.Object)
*/
@Override
public void setPrimaryItem(ViewGroup container, int position,
Object object) {
super.setPrimaryItem(container, position, object);
mPrimaryItem = (Fragment) object;
}
/** (non-Javadoc)
* @see Android.support.v4.view.PagerAdapter#getItemPosition(Java.lang.Object)
*/
@Override
public int getItemPosition(Object object) {
if (object == mPrimaryItem) {
return POSITION_UNCHANGED;
}
return POSITION_NONE;
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
mPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) { }
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) { }
@Override
public void onPageScrollStateChanged(int arg0) { }
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) { }
@Override
public void onPageSelected(int position) {
mActionBar.setSelectedNavigationItem(position);
}
/**
* This method removes the pages from ViewPager
*/
public void removePages() {
mActionBar.removeAllTabs();
//call to ViewPage to remove the pages
vp.removeAllViews();
mFragments.clear();
//make this to update the pager
vp.setAdapter(null);
vp.setAdapter(pagerAdapter);
}
}
動的に削除および追加するためのコード
//remove the pages. basically call to method removeAllViews from `ViewPager`
pagerAdapter.removePages();
pagerAdapter.addPage(pass your fragment);
Peri Hartmanのアドバイスの後、それはnull do ViewPagerアダプタを設定し、ビューが削除された後に再びアダプタを配置した後に動作し始めました。これ以前は、ページ0はリストの内容を表示していませんでした。
ありがとう。
このトピックに関してはかなりの数の議論があります
よく見ますが、POSITION_NONEを使用するのはのような方法ではないようです。メモリ的には非常に非効率的です。
この質問では、 Alvaroのアプローチ を使用することを検討する必要があります。
...は、新しいビューをインスタンス化するときの
setTag()のinstantiateItem()メソッドに対するものです。notifyDataSetChanged()を使う代わりに、更新したいビューを見つけるためにfindViewWithTag()を使うことができます。
これが SOコードで答える です。
私も同じようなプログラムをしました。これが助けになることを願っています。最初のアクティビティでは、4つのグリッドデータを選択できます。次のアクティビティでは、2つの必須ページを含むビューページャがあります。さらに4ページがあり、選択したグリッドデータに対応して表示されます。
主な活動は以下の通りです。
package com.example.jeffy.viewpagerapp;
import Android.content.Context;
import Android.content.Intent;
import Android.content.SharedPreferences;
import Android.database.Cursor;
import Android.database.SQLException;
import Android.database.sqlite.SQLiteDatabase;
import Android.database.sqlite.SQLiteOpenHelper;
import Android.os.Bundle;
import Android.os.Parcel;
import Android.support.design.widget.FloatingActionButton;
import Android.support.design.widget.Snackbar;
import Android.support.v7.app.AppCompatActivity;
import Android.support.v7.widget.Toolbar;
import Android.util.Log;
import Android.view.View;
import Android.view.Menu;
import Android.view.MenuItem;
import Android.widget.AdapterView;
import Android.widget.Button;
import Android.widget.GridView;
import Java.lang.reflect.Array;
import Java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
SharedPreferences pref;
SharedPreferences.Editor editor;
GridView gridView;
Button button;
private static final String DATABASE_NAME = "dbForTest.db";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_NAME = "diary";
private static final String TITLE = "id";
private static final String BODY = "content";
DBHelper dbHelper = new DBHelper(this);
ArrayList<String> frags = new ArrayList<String>();
ArrayList<FragmentArray> fragmentArray = new ArrayList<FragmentArray>();
String[] selectedData;
Boolean port1=false,port2=false,port3=false,port4=false;
int Iport1=1,Iport2=1,Iport3=1,Iport4=1,location;
// This Data show in grid ( Used by adapter )
CustomGridAdapter customGridAdapter = new CustomGridAdapter(MainActivity.this,GRID_DATA);
static final String[ ] GRID_DATA = new String[] {
"1" ,
"2",
"3" ,
"4"
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
frags.add("TabFragment3");
frags.add("TabFragment4");
frags.add("TabFragment5");
frags.add("TabFragment6");
dbHelper = new DBHelper(this);
dbHelper.insertContact(1,0);
dbHelper.insertContact(2,0);
dbHelper.insertContact(3,0);
dbHelper.insertContact(4,0);
final Bundle selected = new Bundle();
button = (Button) findViewById(R.id.button);
pref = getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
editor = pref.edit();
gridView = (GridView) findViewById(R.id.gridView1);
gridView.setAdapter(customGridAdapter);
gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
location = position + 1;
if (position == 0) {
Iport1++;
Iport1 = Iport1 % 2;
if (Iport1 % 2 == 1) {
//dbHelper.updateContact(1,1);
view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
dbHelper.updateContact(1,1);
} else {
//dbHelper.updateContact(1,0);
view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
dbHelper.updateContact(1, 0);
}
}
if (position == 1) {
Iport2++;
Iport1 = Iport1 % 2;
if (Iport2 % 2 == 1) {
//dbHelper.updateContact(2,1);
view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
dbHelper.updateContact(2, 1);
} else {
//dbHelper.updateContact(2,0);
view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
dbHelper.updateContact(2,0);
}
}
if (position == 2) {
Iport3++;
Iport3 = Iport3 % 2;
if (Iport3 % 2 == 1) {
//dbHelper.updateContact(3,1);
view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
dbHelper.updateContact(3, 1);
} else {
//dbHelper.updateContact(3,0);
view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
dbHelper.updateContact(3, 0);
}
}
if (position == 3) {
Iport4++;
Iport4 = Iport4 % 2;
if (Iport4 % 2 == 1) {
//dbHelper.updateContact(4,1);
view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
dbHelper.updateContact(4, 1);
} else {
//dbHelper.updateContact(4,0);
view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
dbHelper.updateContact(4,0);
}
}
}
});
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
editor.putInt("port1", Iport1);
editor.putInt("port2", Iport2);
editor.putInt("port3", Iport3);
editor.putInt("port4", Iport4);
Intent i = new Intent(MainActivity.this,Main2Activity.class);
if(Iport1==1)
i.putExtra("3","TabFragment3");
else
i.putExtra("3", "");
if(Iport2==1)
i.putExtra("4","TabFragment4");
else
i.putExtra("4","");
if(Iport3==1)
i.putExtra("5", "TabFragment5");
else
i.putExtra("5","");
if(Iport4==1)
i.putExtra("6", "TabFragment6");
else
i.putExtra("6","");
dbHelper.updateContact(0, Iport1);
dbHelper.updateContact(1, Iport2);
dbHelper.updateContact(2, Iport3);
dbHelper.updateContact(3, Iport4);
startActivity(i);
}
});
}
}
ここでTabFragment1、TabFragment2などはviewpagerに表示されるフラグメントです。そしてそれらはこのプロジェクトの範囲外であるので私はレイアウトを見せていません。
MainActivityはMain2ActivityになりますMain2Activity
package com.example.jeffy.viewpagerapp;
import Android.content.Intent;
import Android.database.Cursor;
import Android.os.Bundle;
import Android.support.design.widget.CollapsingToolbarLayout;
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.support.v4.widget.NestedScrollView;
import Android.support.v7.app.AppCompatActivity;
import Android.support.v7.widget.Toolbar;
import Android.text.TextUtils;
import Android.util.Log;
import Android.view.LayoutInflater;
import Android.view.Menu;
import Android.view.MenuItem;
import Android.view.View;
import Android.widget.FrameLayout;
import Java.util.ArrayList;
public class Main2Activity extends AppCompatActivity {
private ViewPager pager = null;
private PagerAdapter pagerAdapter = null;
DBHelper dbHelper;
Cursor rs;
int port1,port2,port3,port4;
//-----------------------------------------------------------------------------
@Override
public void onCreate (Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
Toolbar toolbar = (Toolbar) findViewById(R.id.MyToolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
CollapsingToolbarLayout collapsingToolbar =
(CollapsingToolbarLayout) findViewById(R.id.collapse_toolbar);
NestedScrollView scrollView = (NestedScrollView) findViewById (R.id.nested);
scrollView.setFillViewport (true);
ArrayList<String > selectedPort = new ArrayList<String>();
Intent intent = getIntent();
String Tab3 = intent.getStringExtra("3");
String Tab4 = intent.getStringExtra("4");
String Tab5 = intent.getStringExtra("5");
String Tab6 = intent.getStringExtra("6");
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("View"));
tabLayout.addTab(tabLayout.newTab().setText("All"));
selectedPort.add("TabFragment1");
selectedPort.add("TabFragment2");
if(Tab3!=null && !TextUtils.isEmpty(Tab3))
selectedPort.add(Tab3);
if(Tab4!=null && !TextUtils.isEmpty(Tab4))
selectedPort.add(Tab4);
if(Tab5!=null && !TextUtils.isEmpty(Tab5))
selectedPort.add(Tab5);
if(Tab6!=null && !TextUtils.isEmpty(Tab6))
selectedPort.add(Tab6);
dbHelper = new DBHelper(this);
// rs=dbHelper.getData(1);
// port1 = rs.getInt(rs.getColumnIndex("id"));
//
// rs=dbHelper.getData(2);
// port2 = rs.getInt(rs.getColumnIndex("id"));
//
// rs=dbHelper.getData(3);
// port3 = rs.getInt(rs.getColumnIndex("id"));
//
// rs=dbHelper.getData(4);
// port4 = rs.getInt(rs.getColumnIndex("id"));
Log.i(">>>>>>>>>>>>>>", "port 1" + port1 + "port 2" + port2 + "port 3" + port3 + "port 4" + port4);
if(Tab3!=null && !TextUtils.isEmpty(Tab3))
tabLayout.addTab(tabLayout.newTab().setText("Tab 0"));
if(Tab3!=null && !TextUtils.isEmpty(Tab4))
tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
if(Tab3!=null && !TextUtils.isEmpty(Tab5))
tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
if(Tab3!=null && !TextUtils.isEmpty(Tab6))
tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
final PagerAdapter adapter = new PagerAdapter
(getSupportFragmentManager(), tabLayout.getTabCount(), selectedPort);
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@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) {
}
});
// setContentView(R.layout.activity_main2);
// Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
// setSupportActionBar(toolbar);
// TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
// tabLayout.addTab(tabLayout.newTab().setText("View"));
// tabLayout.addTab(tabLayout.newTab().setText("All"));
// tabLayout.addTab(tabLayout.newTab().setText("Tab 0"));
// tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
// tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
// tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
// tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
}
}
ViewPagerAdapter Viewpageradapter.class
package com.example.jeffy.viewpagerapp;
import Android.os.Bundle;
import Android.support.v4.app.Fragment;
import Android.support.v4.app.FragmentManager;
import Android.support.v4.app.FragmentStatePagerAdapter;
import Android.support.v4.view.ViewPager;
import Android.view.View;
import Android.view.ViewGroup;
import Java.util.ArrayList;
import Java.util.List;
/**
* Created by Jeffy on 25-01-2016.
*/
public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
List<String> values;
public PagerAdapter(FragmentManager fm, int NumOfTabs, List<String> Port) {
super(fm);
this.mNumOfTabs = NumOfTabs;
this.values= Port;
}
@Override
public Fragment getItem(int position) {
String fragmentName = values.get(position);
Class<?> clazz = null;
Object fragment = null;
try {
clazz = Class.forName("com.example.jeffy.viewpagerapp."+fragmentName);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
try {
fragment = clazz.newInstance();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return (Fragment) fragment;
}
@Override
public int getCount() {
return values.size();
}
}
Main2activity acticity_main2.xmlのレイアウト
<Android.support.design.widget.CoordinatorLayout xmlns:Android="http://schemas.Android.com/apk/res/Android"
xmlns:app="http://schemas.Android.com/apk/res-auto"
Android:id="@+id/main_content"
Android:layout_width="match_parent"
Android:layout_height="match_parent"
Android:fitsSystemWindows="true">
<Android.support.design.widget.AppBarLayout
Android:id="@+id/MyAppbar"
Android:layout_width="match_parent"
Android:layout_height="256dp"
Android:fitsSystemWindows="true">
<Android.support.design.widget.CollapsingToolbarLayout
Android:id="@+id/collapse_toolbar"
Android:layout_width="match_parent"
Android:layout_height="match_parent"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
Android:background="@color/material_deep_teal_500"
Android:fitsSystemWindows="true">
<ImageView
Android:id="@+id/bgheader"
Android:layout_width="match_parent"
Android:layout_height="match_parent"
Android:scaleType="centerCrop"
Android:fitsSystemWindows="true"
Android:background="@drawable/screen"
app:layout_collapseMode="pin" />
<Android.support.v7.widget.Toolbar
Android:id="@+id/MyToolbar"
Android:layout_width="match_parent"
Android:layout_height="?attr/actionBarSize"
app:layout_collapseMode="parallax" />
</Android.support.design.widget.CollapsingToolbarLayout>
</Android.support.design.widget.AppBarLayout>
<Android.support.v4.widget.NestedScrollView
Android:layout_width="match_parent"
Android:id="@+id/nested"
Android:layout_height="match_parent"
Android:layout_gravity="fill_vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<LinearLayout
Android:layout_width="match_parent"
Android:layout_height="wrap_content"
Android:orientation="vertical">
<Android.support.design.widget.TabLayout
Android:id="@+id/tab_layout"
Android:layout_width="match_parent"
Android:layout_height="wrap_content"
Android:layout_below="@+id/MyToolbar"
Android:background="?attr/colorPrimary"
Android:elevation="6dp"
Android:minHeight="?attr/actionBarSize"
Android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>
<Android.support.v4.view.ViewPager
xmlns:Android="http://schemas.Android.com/apk/res/Android"
Android:id="@+id/view_pager"
Android:layout_width="match_parent"
Android:layout_height="match_parent" >
</Android.support.v4.view.ViewPager>
</LinearLayout>
</Android.support.v4.widget.NestedScrollView>
</Android.support.design.widget.CoordinatorLayout>
Mainactivity layout
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:Android="http://schemas.Android.com/apk/res/Android"
xmlns:app="http://schemas.Android.com/apk/res-auto"
xmlns:tools="http://schemas.Android.com/tools"
Android:layout_width="match_parent"
Android:layout_height="match_parent"
Android:paddingBottom="@dimen/activity_vertical_margin"
Android:paddingLeft="@dimen/activity_horizontal_margin"
Android:paddingRight="@dimen/activity_horizontal_margin"
Android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.example.jeffy.viewpagerapp.MainActivity"
tools:showIn="@layout/activity_main">
<LinearLayout
Android:layout_width="match_parent"
Android:layout_height="wrap_content"
Android:orientation="vertical">
<GridView xmlns:Android="http://schemas.Android.com/apk/res/Android"
Android:id="@+id/gridView1"
Android:numColumns="2"
Android:gravity="center"
Android:columnWidth="100dp"
Android:stretchMode="columnWidth"
Android:layout_width="fill_parent"
Android:layout_height="fill_parent" >
</GridView>
<Button
Android:layout_width="match_parent"
Android:layout_height="wrap_content"
Android:text="SAVE"
Android:id="@+id/button" />
</LinearLayout>
</RelativeLayout>
これが誰かに役立つことを願っています...これがあなたを助けてくれたならボタンをクリックしてください
PagerAdaptersの項目を動的に変更するための カスタムPagerAdaptersライブラリ を作成しました。
このライブラリを使うことで、以下のように動的にアイテムを変更することができます。
@Override
protected void onCreate(Bundle savedInstanceState) {
/** ... **/
adapter = new MyStatePagerAdapter(getSupportFragmentManager()
, new String[]{"1", "2", "3"});
((ViewPager)findViewById(R.id.view_pager)).setAdapter(adapter);
adapter.add("4");
adapter.remove(0);
}
class MyPagerAdapter extends ArrayViewPagerAdapter<String> {
public MyPagerAdapter(String[] data) {
super(data);
}
@Override
public View getView(LayoutInflater inflater, ViewGroup container, String item, int position) {
View v = inflater.inflate(R.layout.item_page, container, false);
((TextView) v.findViewById(R.id.item_txt)).setText(item);
return v;
}
}
ThilsライブラリはFragmentsによって作成されたページもサポートします。
私はこの問題に対する良い解決策を見つけました、この解決策はそれを機能させることができ、フラグメントを作り直す必要はありません。
私のポイントは次のとおりです。
- Tab（Fragment）を削除または追加するたびにViewPagerを設定します。
- getItemIdメソッドをオーバーライドし、位置ではなく特定のIDを返します。
ソースコード
package com.zq.testviewpager;
import Android.support.annotation.Nullable;
import Android.support.design.widget.TabLayout;
import Android.support.design.widget.FloatingActionButton;
import Android.support.design.widget.Snackbar;
import Android.support.v7.app.AppCompatActivity;
import Android.support.v7.widget.Toolbar;
import Android.support.v4.app.Fragment;
import Android.support.v4.app.FragmentManager;
import Android.support.v4.app.FragmentPagerAdapter;
import Android.support.v4.view.ViewPager;
import Android.os.Bundle;
import Android.util.Log;
import Android.view.LayoutInflater;
import Android.view.Menu;
import Android.view.MenuItem;
import Android.view.View;
import Android.view.ViewGroup;
import Android.widget.TextView;
import Java.util.ArrayList;
import Java.util.Arrays;
/**
* Created by [email protected] on 2017/5/31.
* Implement dynamic delete or add tab(TAB_C in this test code).
*/
public class MainActivity extends AppCompatActivity {
private static final int TAB_A = 1001;
private static final int TAB_B = 1002;
private static final int TAB_C = 1003;
private static final int TAB_D = 1004;
private static final int TAB_E = 1005;
private Tab[] tabsArray = new Tab[]{new Tab(TAB_A, "A"),new Tab(TAB_B, "B"),new Tab(TAB_C, "C"),new Tab(TAB_D, "D"),new Tab(TAB_E, "E")};
private ArrayList<Tab> mTabs = new ArrayList<>(Arrays.asList(tabsArray));
private Tab[] tabsArray2 = new Tab[]{new Tab(TAB_A, "A"),new Tab(TAB_B, "B"),new Tab(TAB_D, "D"),new Tab(TAB_E, "E")};
private ArrayList<Tab> mTabs2 = new ArrayList<>(Arrays.asList(tabsArray2));
/**
* The {@link Android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {@link Android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will Host the section contents.
*/
private ViewPager mViewPager;
private TabLayout tabLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(mTabs, getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
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();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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;
}else if (id == R.id.action_delete) {
int currentItemPosition = mViewPager.getCurrentItem();
Tab currentTab = mTabs.get(currentItemPosition);
if(currentTab.id == TAB_C){
currentTab = mTabs.get(currentItemPosition == 0 ? currentItemPosition +1 : currentItemPosition - 1);
}
mSectionsPagerAdapter = new SectionsPagerAdapter(mTabs2, getSupportFragmentManager());
mViewPager.setAdapter(mSectionsPagerAdapter);
tabLayout.setupWithViewPager(mViewPager);
mViewPager.setCurrentItem(mTabs2.indexOf(currentTab), false);
return true;
}else if (id == R.id.action_add) {
int currentItemPosition = mViewPager.getCurrentItem();
Tab currentTab = mTabs2.get(currentItemPosition);
mSectionsPagerAdapter = new SectionsPagerAdapter(mTabs, getSupportFragmentManager());
mViewPager.setAdapter(mSectionsPagerAdapter);
tabLayout.setupWithViewPager(mViewPager);
mViewPager.setCurrentItem(mTabs.indexOf(currentTab), false);
return true;
}else
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e("TestViewPager", "onCreate"+getArguments().getInt(ARG_SECTION_NUMBER));
}
@Override
public void onDestroy() {
super.onDestroy();
Log.e("TestViewPager", "onDestroy"+getArguments().getInt(ARG_SECTION_NUMBER));
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
ArrayList<Tab> tabs;
public SectionsPagerAdapter(ArrayList<Tab> tabs, FragmentManager fm) {
super(fm);
this.tabs = tabs;
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
return PlaceholderFragment.newInstance(tabs.get(position).id);
}
@Override
public int getCount() {
return tabs.size();
}
@Override
public long getItemId(int position) {
return tabs.get(position).id;
}
@Override
public CharSequence getPageTitle(int position) {
return tabs.get(position).title;
}
}
private static class Tab {
String title;
public int id;
Tab(int id, String title){
this.id = id;
this.title = title;
}
@Override
public boolean equals(Object obj) {
if(obj instanceof Tab){
return ((Tab)obj).id == id;
}else{
return false;
}
}
}
}
コードは私のところです Github Gist 。
削除するには、これを直接使うことができます。
getSupportFragmentManager().beginTransaction().remove(fragment).
commitAllowingStateLoss();
fragmentは削除したいフラグメントです。