d:id="@+id/nav_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="@navigation/nav_graph"/>
</LinearLayout>
在Activity中添加如下代码
class MainActivity2 : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main2)
}
override fun onSupportNavigateUp(): Boolean {
return Navigation.findNavController(this, R.id.nav_fragment).navigateUp()
}
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
var args = arguments?.let { IndexFragmentArgs.fromBundle(it) }
top_bar_title.text = args!!.topBarTitle
btn_goto_ball.setOnClickListener { Navigation.findNavController(it).navigate(R.id.action_indexFragment_to_ballFragment) }//点击跳转时间
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
var args = arguments?.let { BallFragmentArgs.fromBundle(it) }
top_bar_title.text = args!!.topBarTitle
top_bar_back.visibility = if (args!!.showBack == 1) View.VISIBLE else View.GONE
txt_desc.text = "${args!!.topBarTitle}页面"
top_bar_back.setOnClickListener { Navigation.findNavController(it).popBackStack() }//回退事件
}
好了,Navigation入门讲解完了,上面代码对于Fragment 并非是通过原生的 FragmentManager 和 FragmentTransaction 进行控制的,而是通过以下Navigation.findNavController(params)进行的控制。接下来会对Navigation详细讲解。
导航视图
此属性位于navigation 根节点上,是导航器默认加载在Activity的视图,是必须设置的。
<navigation 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/nav_graph"
app:startDestination="@id/indexFragment">
<fragment android:id="@+id/ballFragment"
android:name="com.fomin.demo.bar.BallFragment"
android:label="BallFragment"
tools:layout="@layout/ball_fragment"/>
</navigation>
navigation可以添加fragment和activity的视图,需要关注的属性android:id和android:name,name是所在Fragmet/Activity类所在包名,id就不解释了,众所周知。
使用参数传递,需要module的build.gradle添加:apply plugin: 'androidx.navigation.safeargs'
<fragment android:id="@+id/ballFragment"
android:name="com.fomin.demo.bar.BallFragment"
android:label="BallFragment"
tools:layout="@layout/ball_fragment">
<argument android:name="topBarTitle"
app:argType="string"
android:defaultValue="足球"/>
</fragment>
视图之间的参数传递属性,argType可以支持string、integer、reference,long,float,boolean和Parcelable对象等。增加属性之后需要Rebuild一下,IDE会生成相关视图的Args类。如:
public class BallFragmentArgs implements NavArgs {
省略....
@NonNull
public String getTopBarTitle() {
return (String) arguments.get("topBarTitle");
}
省略....
}
参数传递
btn_