【发布时间】：2020-07-09 11:22:04
【问题描述】：
我在其中一个应用程序中发现了一个有趣的功能，我想重复一下。该应用程序具有 ViewPager 和 TabLayout 以及内部的一堆片段。 在第一个片段上有一个按钮img1
，按下它，片段被另一个img2替换
当 ads_banner 被移除并且工具栏被替换时， 当向右和向后滑动时，它显示fragment1，请告诉我如何做到这一点。这是我已经写的：
主活动
class MainActivity : AppCompatActivity() {
private var mAdView: AdView? = null
@SuppressLint("ResourceType")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val adRequest = AdRequest.Builder().build()
mAdView = findViewById(R.id.adView)
mAdView!!.loadAd(adRequest)
initTab()
}
fun initTab() {
tab_layout.addTab(tab_layout.newTab().setIcon(R.drawable.image1)
tab_layout.addTab(tab_layout.newTab().setIcon(R.drawable.image2)
tab_layout.addTab(tab_layout.newTab().setIcon(R.drawable.image3)
tab_layout.tabGravity = TabLayout.GRAVITY_FILL
val adapter = MyPagerAdapter(supportFragmentManager, tab_layout.tabCount)
pager.adapter = adapter
pager.offscreenPageLimit = 2
pager.addOnPageChangeListener(TabLayout.TabLayoutOnPageChangeListener(tab_layout))
tab_layout.addOnTabSelectedListener(object : TabLayout.OnTabSelectedListener {
override fun onTabSelected(tab: TabLayout.Tab) {
pager.currentItem = tab.position
if (tab.position == 0) {
tab_layout.getTabAt(0)!!.setIcon(R.drawable.image1_focus)
}
if (tab.position == 1) {
tab_layout.getTabAt(1)!!.setIcon(R.drawable.image2_focus)
}
if (tab.position == 2) {
tab_layout.getTabAt(2)!!.setIcon(R.drawable.image3_focus)
}
}
override fun onTabUnselected(tab: TabLayout.Tab) {
if (tab.position == 0) tab_layout.getTabAt(0)!!.setIcon(R.drawable.image1)
if (tab.position == 1) tab_layout.getTabAt(1)!!.setIcon(R.drawable.image2)
if (tab.position == 2) tab_layout.getTabAt(2)!!.setIcon(R.drawable.image3)
}
override fun onTabReselected(tab: TabLayout.Tab) {
}
})
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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:id="@+id/mainlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white"
android:fitsSystemWindows="true"
android:orientation="vertical"
tools:context=".MainActivity">
<com.google.android.gms.ads.AdView
android:id="@+id/adView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:background="@color/transparent"
app:adSize="SMART_BANNER"
app:adUnitId="@string/banner_key"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
style="@style/MyToolbar"
android:layout_width="match_parent"
android:layout_height="35dp"
android:layout_marginTop="2dp"
android:gravity="center"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/adView"
app:popupTheme="@style/AppTheme.PopupOverlay">
<TextView
android:id="@+id/toolbar_txt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:fontFamily="@font/sf_pro_display_regular"
android:textColor="@color/black"
android:textSize="24sp"
tools:layout_editor_absoluteX="206dp"
tools:layout_editor_absoluteY="7dp" />
</androidx.appcompat.widget.Toolbar>
<androidx.viewpager.widget.ViewPager
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/tab_layout"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/toolbar" />
<com.google.android.material.tabs.TabLayout
android:id="@+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="#fff"
android:elevation="6dp"
android:minHeight="?attr/actionBarSize"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:tabBackground="@drawable/tab_color_selector"
app:tabIndicatorColor="#2196F3"
app:tabIndicatorGravity="top"
app:tabIndicatorHeight="4dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
MyPagerAdapter
class MyPagerAdapter(fm: FragmentManager, internal var mNumOfTabs: Int) : FragmentStatePagerAdapter(fm) {
override fun getItem(position: Int): Fragment {
when (position) {
0 -> {
return RootFragment()
// return Fragment1()
}
1 -> {
return Fragment2()
}
2 -> {
return Fragment3()
}
}
}
override fun getCount(): Int {
return mNumOfTabs
}
}
片段1
class Fragment1: Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val view = inflater.inflate(R.layout.fragment_1, container, false)
return view
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
btnfr1.setOnClickListener {
val trans = fragmentManager!!.beginTransaction()
trans.replace(R.id.root_frame, Fragment4())
trans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
trans.addToBackStack(null)
trans.commit()
}
}
根片段
class RootFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val view = inflater.inflate(R.layout.root_fragment, container, false)
val transaction = fragmentManager!!.beginTransaction()
transaction.replace(R.id.root_frame, Fragment1())
transaction.commit()
return view
}
}
root_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/root_frame" >
</FrameLayout>
在 Fragment1 中，只有调用 Fragment4 的按钮。试着在这里做https://www.codexpedia.com/android/android-viewpager-fragment-swap/ 原来是用Fragment4替换Fragment1，但是刷的时候不知道怎么重置Fragment4，也不明白怎么替换Toolbar和去除广告。
【问题讨论】：
标签： android kotlin android-fragments android-viewpager fragment