![](/img/trans.png)
[英]Android BottomNavigation fragment show/hide after App (screen) rotate
[英]View pager holds old fragment after rotate screen
我有一個視圖尋呼機,有4個片段。 (即時通訊使用FragmentStatePagerAdapter)
每個片段都有一個“FrameLayout / container”,我添加並替換了許多片段。
一切正常,但是當我改變屏幕方向時, 線條的第一個片段將恢復到實際片段。 然后兩者同時出現。
我用一個例子說明了發生了什么:
[當我旋轉屏幕]
http://i.stack.imgur.com/kxaVn.png
我的主要活動代碼
class MainActivity : AppCompatActivity() {
val numPages = 4
var pager: ViewPager? = null
private val TITLES = arrayOf("Feed", "Catalogo","Guia","Rendimento")
var menuImages:Array<ImageView>?=null
var menuTexts:Array<TextView>?=null
var fragments = arrayListOf<Fragment>()
private var fragmentCreated1: FeedContainerFragment? = null
private var fragmentCreated2: CatalogContainerFragment? = null
private var fragmentCreated3: GuideContainerFragment? = null
private var fragmentCreated4: TestContainerFragment? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_default)
fragments.add(FeedContainerFragment())
fragments.add(CatalogContainerFragment())
fragments.add(GuideContainerFragment())
fragments.add(TestContainerFragment())
menuImages= arrayOf(findViewById(R.id.icon_feed) as ImageView,
findViewById(R.id.icon_catalogue) as ImageView,
findViewById(R.id.icon_guide) as ImageView,
findViewById(R.id.icon_form) as ImageView)
menuTexts= arrayOf(findViewById(R.id.text_feed) as TextView,
findViewById(R.id.text_catalogue) as TextView,
findViewById(R.id.text_guide) as TextView,
findViewById(R.id.text_form) as TextView)
menuImages?.get(0)?.setColorFilter(ContextCompat.getColor(baseContext,R.color.colorAccent))
menuTexts?.get(0)?.setTextColor(ContextCompat.getColor(baseContext,R.color.colorAccent))
//view pager
pager = findViewById(R.id.pager) as ViewPager
val pagerAdapter = ScreenSlidePagerAdapter(supportFragmentManager)
pager?.adapter = pagerAdapter
pager?.offscreenPageLimit = 4
pager?.addOnPageChangeListener(object : ViewPager.OnPageChangeListener {
override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {
}
override fun onPageSelected(position: Int) {
pager?.adapter?.notifyDataSetChanged()
repaintMenuDefaultColor()
menuImages?.get(position)?.setColorFilter(ContextCompat.getColor(baseContext,R.color.colorAccent))
menuTexts?.get(position)?.setTextColor(ContextCompat.getColor(baseContext,R.color.colorAccent))
}
override fun onPageScrollStateChanged(state: Int) {
}
})
//Navigation Menus
MenuUtils.generateMaterialMenu(this)
MenuUtils.generateBottomMenu(this, this.pager!!)
}
private inner class ScreenSlidePagerAdapter(fm: FragmentManager) : FragmentStatePagerAdapter(fm) {
override fun getCount(): Int {
return numPages
}
override fun getItem(position: Int): Fragment {
when(position) {
0->return FeedContainerFragment()
1->return CatalogContainerFragment()
2->return GuideContainerFragment()
3->return TestContainerFragment()
else->return FeedContainerFragment()
}
}
override fun getPageTitle(position: Int): CharSequence {
return TITLES[position]
}
override fun getItemPosition(obj: Any?): Int {
if (obj is Refreshable) {
return POSITION_NONE
}
return super.getItemPosition(obj)
}
override fun instantiateItem(container:ViewGroup, position:Int):Any {
val createdFragment = super.instantiateItem(container, position) as Fragment
when (position) {
0 -> fragmentCreated1 = createdFragment as FeedContainerFragment
1 -> fragmentCreated2 = createdFragment as CatalogContainerFragment
2 -> fragmentCreated3 = createdFragment as GuideContainerFragment
3 -> fragmentCreated4 = createdFragment as TestContainerFragment
}
return createdFragment
}
}
override fun onBackPressed() {
if (fragmentManager.backStackEntryCount > 0) {
fragmentManager.popBackStack()
} else {
super.onBackPressed()
}
}
fun repaintMenuDefaultColor(){
this.menuImages?.map {
it.setColorFilter(ContextCompat.getColor(baseContext,R.color.menu_icon))
}
this.menuTexts?.map {
it.setTextColor(ContextCompat.getColor(baseContext,R.color.menu_text))
}
}
}
歡迎任何幫助!
編輯:實際上,正在發生的是ViewPager將實際片段保持為“Ghost”,然后恢復該行的第一個片段。
有沒有辦法清理屏幕並刪除“鬼”?
編輯2:找到解決方案。 在每個“容器”上添加片段之前,我需要驗證片段的實例是否已經存在。問題不在ViewPager或Adapter上。 每當我改變方向時,都會包含一個新的片段。
所以,只需將驗證放在下面:
if(savedInstanceState == null) {
activity
.supportFragmentManager
.beginTransaction()
.add(R.id.containerGuide, YourFragment())
.commit()
}
旋轉屏幕時,重新創建活動和碎片,使其從位置0開始。
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