ViewPager 中的膨胀布局

Question

这是我的 viewpager xml

<android.support.v4.view.ViewPager
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />

如何在 onCreateView 中扩充布局资源？

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {

}

我试过类似的东西

val rootView = inflater.inflate(resID, container, false)
return rootView

但这显示了白色活动

这是我要膨胀的布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.constraint.Guideline
    android:id="@+id/guideline"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    app:layout_constraintGuide_percent="0.9" />

<ListView
    android:layout_width="368dp"
    android:layout_height="444dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:layout_constraintBottom_toTopOf="@+id/guideline"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:text="Button"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="@+id/guideline" />
 </android.support.constraint.ConstraintLayout>

Answer 1

这将使 viewpager 布局膨胀：

override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?,
                            savedInstanceState: Bundle?): View? {
    return inflater?.inflate(R.layout.viewpager, container, false) // provide the name of your layout  
  }

如果您想显示 XML（您提供），那么您需要创建一个包含 XML 的片段。您需要创建一个 ViewPagerAdapter 以在 viewPager 上显示片段。

例子：

your_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.constraint.Guideline
    android:id="@+id/guideline"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    app:layout_constraintGuide_percent="0.9" />

<ListView
    android:layout_width="368dp"
    android:layout_height="444dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:layout_constraintBottom_toTopOf="@+id/guideline"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:text="Button"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="@+id/guideline" />
 </android.support.constraint.ConstraintLayout>

YourFragment.kt

import android.os.Bundle
import android.support.v4.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView

class YourFragment : Fragment() {

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {

        val view = inflater.inflate(R.layout.your_layout, container, false)
        return view
    }
}

还有ViewPagerAdapter.kt

import android.support.v4.app.Fragment
import android.support.v4.app.FragmentManager
import android.support.v4.app.FragmentPagerAdapter

class ViewPagerAdapter internal constructor(fm: FragmentManager) : FragmentPagerAdapter(fm) {

    private val COUNT = 3

    override fun getItem(position: Int): Fragment? {
        var fragment: Fragment? = null
        when (position) {
            0 -> fragment = YourFragment()
            1 -> fragment = YourFragment()
            2 -> fragment = YourFragment()
        }

        return fragment
    }

    override fun getCount(): Int {
        return COUNT
    }

    override fun getPageTitle(position: Int): CharSequence? {
        return " "
    }
}

从你的 viewpager Fragment 中使用这个：

override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?,
                                savedInstanceState: Bundle?): View? {
        val view = inflater?.inflate(R.layout.viewpager, container, false) // provide the name of your layout  
        val viewPager = view.findViewById<ViewPager>(R.id.viewPager)
        if (viewPager != null) {
            val adapter = ViewPagerAdapter(supportFragmentManager)
            viewPager.adapter = adapter
        }
        return view
      }

Answer 2

在填充片段后设计您的适配器。

private class MyPagerAdapter extends FragmentPagerAdapter {

        MyPagerAdapter(FragmentManager fragmentManager)
        {
            super(fragmentManager);
        }
        @Override
        public Fragment getItem(int position) {
            switch(position){
                case 0: return fragment1.newInstance();
                case 1: return fragment2.newInstance();
                case 2: return fragment3.newInstance();
                default: return fragment1.newInstance();
            }

        }

并且在最后设置的适配器到 viewpager 像这样

vPager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));