Bottom NavigationͰ λϒͷঢ়ଶΛอ࣋͢Δ Keisuke Kobayashi / @kobakei shibuya.apk #17

About me • Keisuke Kobayashi • GitHub, Qiita: kobakei • Twitter: kobakei122 • Kyash, Inc

YouTubeͷ Bottom Navigation

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 ͨ͠ঢ়ଶ

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εΫϩʔϧҐஔ͕ લճͷ··

λϒ੾Γସ͑࣌ʹ
 ঢ়ଶΛอ࣋Ͱ͖ͯΔʂ

Ͳ͏΍ͬͯʁ

࣮૷ • ViewPagerΛ࢖͏ • λϒબ୒࣌ʹɺsetSelectionͰϖʔδΛ੾Γସ͑Δ • εϫΠϓͰͷ੾Γସ͑͸ΨΠυϥΠϯతʹNGͳͷͰɺεϫ ΠϓΛແޮԽ͓ͯ͘͠ • YouTube΋ଟ෼͜ͷ࣮૷ • uiautomatorviewerͰViewPagerΛ֬ೝ

class FixedViewPager @JvmOverloads constructor( context: Context, attrs: AttributeSet? = null ): ViewPager(context, attrs) { override fun onTouchEvent(ev: MotionEvent?): Boolean { return false } override fun onInterceptTouchEvent(ev: MotionEvent?): Boolean { return false } }

class FixedViewPager @JvmOverloads constructor( context: Context, attrs: AttributeSet? = null ): ViewPager(context, attrs) { override fun onTouchEvent(ev: MotionEvent?): Boolean { return false } override fun onInterceptTouchEvent(ev: MotionEvent?): Boolean { return false } } λονΛແޮԽ

class MainPagerAdapter(fm: FragmentManager): FragmentPagerAdapter(fm) { override fun getCount(): Int { return 3 } override fun getItem(position: Int): Fragment { return when (position) { 0 -> OneFragment.newInstance() 1 -> TwoFragment.newInstance() 2 -> ThreeFragment.newInstance() else -> throw IllegalArgumentException() } } }

class MainPagerAdapter(fm: FragmentManager): FragmentPagerAdapter(fm) { override fun getCount(): Int { return 3 } override fun getItem(position: Int): Fragment { return when (position) { 0 -> OneFragment.newInstance() 1 -> TwoFragment.newInstance() 2 -> ThreeFragment.newInstance() else -> throw IllegalArgumentException() } } } λϒͷ਺

class MainPagerAdapter(fm: FragmentManager): FragmentPagerAdapter(fm) { override fun getCount(): Int { return 3 } override fun getItem(position: Int): Fragment { return when (position) { 0 -> OneFragment.newInstance() 1 -> TwoFragment.newInstance() 2 -> ThreeFragment.newInstance() else -> throw IllegalArgumentException() } } } ֤λϒͷFragmentΛฦ͢

// MainActivity.kt override fun onCreate(savedInstanceState: Bundle?) { // লུ pager.adapter = MainPagerAdapter(supportFragmentManager) bottomBar.setOnTabSelectListener { tabId -> when (tabId) { R.id.tab1 -> showTab1() R.id.tab2 -> showTab2() R.id.tab3 -> showTab3() } } }

// MainActivity.kt override fun onCreate(savedInstanceState: Bundle?) { // লུ pager.adapter = MainPagerAdapter(supportFragmentManager) bottomBar.setOnTabSelectListener { tabId -> when (tabId) { R.id.tab1 -> showTab1() R.id.tab2 -> showTab2() R.id.tab3 -> showTab3() } } } λϒબ୒࣌ʹɺදࣔ಺༰Λ੾Γସ͑

// MainActivity.kt private fun showTab1() { // Clear back stack (1..supportFragmentManager.backStackEntryCount).forEach { supportFragmentManager.popBackStack() } // Change page without animation pager.setCurrentItem(0, false) }

ϥΠϑαΠΫϧͷ໰୊ • ͋Δλϒ͕දࣔ͞Εͨͱ͖ʹԿ͔ॲཧΛͨ͠ ͍৔߹ɺద੾ͳϥΠϑαΠΫϧΠϕϯτ͕ͳ͍

Why? • ViewPager͸εϜʔζʹεϫΠϓͰ͖ΔΑ͏ʹ ͢ΔͨΊɺද͍ࣔͯ͠Δλϒͱ྆ྡͷλϒΛ ද͍ࣔͯ͠Δ • λϒ͕දࣔ͞ΕΔΑΓઌʹonResume͕ݺ͹ ΕΔ

ղܾࡦ • BottomBarͷλϒબ୒ɾඇબ୒ΠϕϯτΛ Fragmentʹ౉͢

// ֤λϒͷFragement͸͜ͷΠϯλϑΣʔεΛ࣮૷͢Δ interface RootFragment { fun onTabSelected() fun onTabUnselected() }

class MainPagerAdapter(fm: FragmentManager): FragmentPagerAdapter(fm) { var currentFragment: Fragment? = null override fun getCount(): Int {...} override fun getItem(position: Int): Fragment {...} override fun setPrimaryItem(container: ViewGroup?, position: Int, obj: Any?) { if (currentFragment != obj) { currentFragment = obj as Fragment } super.setPrimaryItem(container, position, obj) } }

class MainPagerAdapter(fm: FragmentManager): FragmentPagerAdapter(fm) { var currentFragment: Fragment? = null override fun getCount(): Int {...} override fun getItem(position: Int): Fragment {...} override fun setPrimaryItem(container: ViewGroup?, position: Int, obj: Any?) { if (currentFragment != obj) { currentFragment = obj as Fragment } super.setPrimaryItem(container, position, obj) } } ݱࡏͷFragmentΛอ࣋

// MainActivity.kt
 override fun onCreate(savedInstanceState: Bundle?) { // ... // ViewPager pager.adapter = MainPagerAdapter(supportFragmentManager) // bottomBar.setOnTabSelectListener { tabId -> dispatchUnselect() when (tabId) { R.id.tab1 -> showTab1() R.id.tab2 -> showTab2() R.id.tab3 -> showTab3() } dispatchSelect() } }

// MainActivity.kt override fun onCreate(savedInstanceState: Bundle?) { // ... // ViewPager pager.adapter = MainPagerAdapter(supportFragmentManager) // bottomBar.setOnTabSelectListener { tabId -> dispatchUnselect() when (tabId) { R.id.tab1 -> showTab1() R.id.tab2 -> showTab2() R.id.tab3 -> showTab3() } dispatchSelect() } } Fragment੾ସͷલޙͰ
 ΠϕϯτΛൃՐ

private fun dispatchSelect() { val mainAdapter = pager.adapter as? MainPagerAdapter val fragment = mainAdapter?.currentFragment as? RootFragment fragment?.onTabSelected() } private fun dispatchUnselect() { val mainAdapter = pager.adapter as? MainPagerAdapter val fragment = mainAdapter?.currentFragment as? RootFragment fragment?.onTabUnselected() }

·ͱΊ • BottomNavigationͷλϒͷঢ়ଶอ࣋ʹ͸ɺ
 εϫΠϓ͠ͳ͍ViewPagerΛ࢖͏ • දࣔɾඇදࣔ࣌ʹԿ͔͍ͨ͠৔߹͸ɺ
 λϒબ୒ɾඇબ୒ΠϕϯτΛFragmentʹ౉͢

Thanks!