目标
实现底部导航栏
效果图
主要代码
- 添加依赖:
implementation 'com.google.android.material:material:1.2.1'
- 布局文件: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">
<FrameLayout
android:id="@+id/ll_frameLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@id/bottomNavigationView" />
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="@+id/bottomNavigationView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
app:itemIconTint="@drawable/bottom_navigation_item_selector"
app:itemTextColor="@drawable/bottom_navigation_item_selector"
app:menu="@menu/main_bottom_navigation" />
</RelativeLayout>
- 主界面代码:MainActivity
class MainActivity : AppCompatActivity() {
private var lastIndex = 0
private var mFragments = mutableListOf<Fragment>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
initBottomNavigation()
initData()
}
private fun initData() {
mFragments = ArrayList()
mFragments.add(Fragment1())
mFragments.add(Fragment2())
// 初始化展示MessageFragment
setFragmentPosition(0)
}
private fun initBottomNavigation() {
bottomNavigationView.setOnNavigationItemSelectedListener(BottomNavigationView.OnNavigationItemSelectedListener { item ->
when (item.itemId) {
R.id.menu_message -> setFragmentPosition(0)
R.id.menu_contacts -> setFragmentPosition(1)
else -> { }
}
true
})
}
private fun setFragmentPosition(position: Int) {
val ft = supportFragmentManager.beginTransaction()
val currentFragment = mFragments[position]
val lastFragment = mFragments[lastIndex]
lastIndex = position
ft.hide(lastFragment)
if (!currentFragment.isAdded) {
supportFragmentManager.beginTransaction().remove(currentFragment).commit()
ft.add(R.id.ll_frameLayout, currentFragment)
}
ft.show(currentFragment)
ft.commitAllowingStateLoss()
}
}
- Fragment
class Fragment1 : Fragment() {
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val tv = TextView(context)
tv.text = "第一页"
tv.gravity = Gravity.CENTER
return tv
}
}
class Fragment2 : Fragment() {
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val tv = TextView(context)
tv.text = "第二页"
tv.gravity = Gravity.CENTER
return tv
}
}
- 菜单:main_bottom_navigation.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
android:id="@+id/menu_message"
android:enabled="true"
android:icon="@mipmap/ic_message"
android:title="第一页"
app:showAsAction="ifRoom" />
<item
android:id="@+id/menu_contacts"
android:enabled="true"
android:icon="@mipmap/ic_contacts"
android:title="第二页"
app:showAsAction="ifRoom" />
</menu>
完整源代码
https://gitee.com/cxyzy1/navigationDemo/tree/master/bottomNavigationView
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