随着业务的发展,我们需要根据不同角色的权限判断显示对应的tab项,在此我选择用BottomNavigationView。
核心代码:
private lateinit var navigation: BottomNavigationView
private var homeFragment: HomeFragment? = null
private var mineFragment: MineFragment? = null
private var claimFragment: ClaimFragment? = null
private var isFragment: Fragment? = null
private val mVM by viewModels<MainVM>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
navigation = findViewById(R.id.bottom_navigation)
initNavigate()
initFragment(savedInstanceState)
}
private fun initNavigate() {
navigation.menu.clear()
navigation.itemIconTintList = null
mVM.getBottomTab().forEach {
navigation.menu.add(it.groupId, it.homeId, it.order, it.name)
navigation.menu.findItem(it.homeId).apply {
setIcon(it.drawableId)
actionView = getImageButton()
}
}
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener)
}
private fun getImageButton(): ImageButton {
val imageButton = ImageButton(this)
imageButton.setOnLongClickListener {
false
}
return imageButton
}
private fun initFragment(savedInstanceState: Bundle?) {
//判断activity是否重建,如果不是,则不需要重新建立fragment.
if (savedInstanceState == null) {
val fm = supportFragmentManager
val ft = fm.beginTransaction()
if (homeFragment == null) {
homeFragment = HomeFragment()
}
isFragment = homeFragment
ft.replace(R.id.fl_container, homeFragment!!).commit()
}
}
private val mOnNavigationItemSelectedListener =
BottomNavigationView.OnNavigationItemSelectedListener { item ->
when (item.itemId) {
R.id.id_home -> {
if (homeFragment == null) {
homeFragment = HomeFragment()
}
switchContent(isFragment, homeFragment!!)
return@OnNavigationItemSelectedListener true
}
R.id.id_claim -> {
if (claimFragment == null) {
claimFragment = ClaimFragment()
}
switchContent(isFragment, claimFragment!!)
return@OnNavigationItemSelectedListener true
}
R.id.id_mine -> {
if (mineFragment == null) {
mineFragment = MineFragment()
}
switchContent(isFragment, mineFragment!!)
return@OnNavigationItemSelectedListener true
}
}
false
}
private fun switchContent(from: Fragment?, to: Fragment) {
if (isFragment !== to) {
isFragment = to
val fm: FragmentManager = supportFragmentManager
//添加渐隐渐现的动画
val ft: FragmentTransaction = fm.beginTransaction()
if (!to.isAdded) {// 先判断是否被add过
if (from != null) {
ft.hide(from).add(R.id.fl_container, to).commit()
}
} else {
if (from != null) {
ft.hide(from).show(to).commit()
}
}
}
}
数据源:
fun getBottomTab(): List<HomeMenuBean> {
return listOf(
HomeMenuBean(
0, R.id.id_home, 0,
R.drawable.nav_home_home,
SysUtil.getString(R.string.home)
),
HomeMenuBean(
0, R.id.id_claim, 1,
R.drawable.nav_home_claim,
SysUtil.getString(R.string.claim)
),
HomeMenuBean(
0, R.id.id_mine, 2,
R.drawable.nav_home_mine,
SysUtil.getString(R.string.mine)
)
)
}
实体类:
data class HomeMenuBean(
val groupId: Int,
val homeId: Int,
val order: Int,
val drawableId: Int,
val name: String
)
Layout:
<?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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".main.MainActivity">
<FrameLayout
android:id="@+id/fl_container"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/bottom_navigation"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="@+id/bottom_navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/white"
app:itemHorizontalTranslationEnabled="false"
app:itemTextColor="@color/bottom_navigate_text_color"
app:labelVisibilityMode="labeled"
app:itemBackground="@null"
app:layout_constraintBottom_toBottomOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
添加ids:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<item name="id_home" type="id" />
<item name="id_claim" type="id" />
<item name="id_mine" type="id" />
</resources>