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[英]Android ViewPager/PagerAdapter with Data Binding and instantiateItem not executing active view
[英]ANDROID: ViewPager with different Fragments in instantiateItem method
我使用ViewPager
創建向左滑動的片段,現在我想在每個片段頁面中插入片段。
activityMain.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
...
android:orientation="vertical">
<android.support.v4.view.ViewPager
android:id="@+id/myviewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
<devlight.io.library.ntb.NavigationTabBar
android:id="@+id/ntb_horizontal"
app:ntb_swiped="true"/>
</android.support.design.widget.CoordinatorLayout>
這個: tab0_fragment.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="40dp"
android:textSize="30sp"
android:gravity="center"
android:id="@+id/textView"
android:layout_centerHorizontal="true"
android:textColor="@android:color/holo_green_dark"
android:text="Social\nFragment"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:autoLink="web"
android:textSize="15sp"
android:layout_marginTop="10dp"
android:layout_centerHorizontal="true"
android:text="androidbelieve.com"
android:textColor="#000"
android:layout_below="@+id/textView"
android:textStyle="italic"/>
</RelativeLayout>
我有一個ViewPager
在mainActivity.java
final ViewPager viewPager = (ViewPager) findViewById(R.id.myviewpager);
viewPager.setAdapter(new PagerAdapter() {
...
...
}
我嘗試通過片段布局在viewpager中打開一個屏幕。
我試試這個:
final ViewPager viewPager = (ViewPager) findViewById(R.id.myviewpager);
viewPager.setAdapter(new PagerAdapter() {
...
public Object instantiateItem(final ViewGroup container, final int position) {
if (position == 0)
{
final View view = LayoutInflater.from(getBaseContext()).inflate(R.layout.fragment_tab0, null, false);
FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.myviewpager,new tab0Fragment()).commit();
container.addView(view);
return view;
}
else if (position == 1)
...
}
...
}
AND tab0Fragment.java
public class tab0Fragment extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_tab0,null);
}
}
我是機器人中的菜鳥。 怎么能糾正這個代碼?
解決方案:答案不是我的答案,但這對我有很大的幫助。
根據@Mr。 Rabbit ans @Amit Upadhyay我將頂級代碼更改為:
@Override
public Object instantiateItem(final ViewGroup container, final int position) {
if (position == 0)
{
final View view = LayoutInflater.from(getBaseContext()).inflate(R.layout.fragment_tab0, null, false);
MyAdapter adapter = new MyAdapter(getSupportFragmentManager());
adapter.addFragment(new tab0Fragment(), getResources().getString(R.string.tab0));
container.addView(view);
return view;
}
else if (position == 1)
{
並根據@Mr添加MyAdapter類。 兔子的答案。
希望能幫助別人。
嘗試將適配器和代碼分開。
MyAdapter.java
public class MyAdapter extends FragmentPagerAdapter{
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public MyAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
創建你的碎片
FragmentOne.java
public class FragmentOne extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_one, container, false);
return view;
}
}
FragmentTwo.java
public class FragmentTwo extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_two, container, false);
return view;
}
}
在您的活動中設置您的viewpager。
final ViewPager viewPager = (ViewPager) findViewById(R.id.myviewpager);
MyAdapter adapter = new MyAdapter(getSupportFragmentManager());
// Add your fragments in adapter.
FragmentOne fragmentOne = new FragmentOne();
adapter.addFragment(fragmentOne, getResources().getString(R.string.fragment_one_title));
FragmentTwo fragmentTwo = new FragmentTwo();
adapter.addFragment(fragmentTwo, getResources().getString(R.string.fragment_two_title));
viewPager.setAdapter(adapter);
然后最后使用ViewPager設置NavigationTabBar。
final NavigationTabBar navigationTabBar = (NavigationTabBar) findViewById(R.id.ntb_horizontal);
navigationTabBar.setViewPager(viewPager, 2);
為此,您可以創建自定義ViewPagerAdapter。 例如:
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import java.util.ArrayList;
/**
* Created by aupadhyay on 1/5/17.
*/
public class ViewPagerAdapter extends FragmentPagerAdapter {
ArrayList<Fragment> fragments = new ArrayList<>();
ArrayList<String> tabTitles = new ArrayList<>();
public void addFragments(Fragment fragment, String tabTitle)
{
this.fragments.add(fragment);
this.tabTitles.add(tabTitle);
}
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return fragments.get(position);
}
@Override
public int getCount() {
return fragments.size();
}
@Override
public CharSequence getPageTitle(int position) {
return tabTitles.get(position);
}
}
現在你可以在viewpager上設置適配器,如下所示:
final ViewPager viewPager = (ViewPager) findViewById(R.id.myviewpager);
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
viewPagerAdapter.addFragments(new Tab0Fragment(), "First");
viewPagerAdapter.addFragments(new Tab1Fragment(), "Second");
viewPagerAdapter.addFragments(new Tab2Fragment(), "Third");
// add more if required.
viewPager.setAdapter(viewPagerAdapter);
Tab0Fragment
, Tab1Fragment
, Tab1Fragment
是您在viewpager中添加的片段。
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