首先記錄一個坑:no current navigation node
06-26 14:42:25.787 25913-25913/com.bluetree.bytepay2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.bluetree.bytepay2, PID: 25913
java.lang.IllegalStateException: no current navigation node
at androidx.navigation.NavController.navigate(NavController.java:764)
at androidx.navigation.NavController.navigate(NavController.java:744)
at androidx.navigation.NavController.navigate(NavController.java:730)
at androidx.navigation.NavController.navigate(NavController.java:718)
at com.bluetree.bytepay2.sample.BlankFragment$1.onClick(BlankFragment.java:83)
at android.view.View.performClick(View.java:5264)
at android.view.View$PerformClick.run(View.java:21297)
at android.os.Handler.handleCallback(Handler.java:743)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:150)
at android.app.ActivityThread.main(ActivityThread.java:5546)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:684)
解決方案:navigation.xml 中的Fragment繼承了NavHostFragment,取消繼承就可以了!
Navigation導航組件
概述
Navigation是什麼,有什麼意義,內涵之類的這裏就不展開篇幅講了,能貼圖片絕不多說半句廢話。這篇文章只做一個引入的Navigation的用途,適合新手上路。簡單來說,可以用Navigation來進行一些簡單的,並直觀的頁面跳轉。
使用步驟
引入庫就不提,因爲當你使用到Navigation的時候,AS會自動幫你導入的,下面簡單介紹一下如何使用Navigation
- 創建navigation目錄
- 創建navigation.xml文件
- 首先創建一個簡單的Activity(SampleNavigationActivity)
- 在佈局文件(R.layout.activity_sample_navigation)中引入androidx.navigation.fragment.NavHostFragment
- 創建兩個普通的Fragment(BlankFragment1,BlankFragment2)
- 打開navigation.xml,把兩個fragment添加進去。用箭頭直觀地展示跳轉邏輯。
- 通過一句代碼實現跳轉邏輯
具體實現
創建navigation目錄
res右鍵選擇新建資源目錄
創建navigation資源文件
navigation目錄右鍵,如圖依次選擇
<?xml version="1.0" encoding="utf-8"?>
<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/navigation"
>
<!--todo 添加fragment進行愉快地拖拽-->
</navigation>
新建activity
public class SampleNavigationActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sample_navigation);
}
}
佈局文件中添加navigation容器
如下圖,引入NavHostFragment,app:defaultNavHost設置默認的navigation文件,並且攔截返回事件
app:navGraph用於指定navigation.xml文件
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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=".sample.SampleNavigationActivity">
<fragment
android:id="@+id/fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="@navigation/navigation" />
</FrameLayout>
創建n個Fragment用於切換
Fragment2也是一樣的,這裏不重複寫了
private const val ARG_PARAM1 = "param1"
private const val ARG_PARAM2 = "param2"
/**
* A simple [Fragment] subclass.
*
*/
class BlankFragment1 : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_blank1, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
}
}
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".sample.BlankFragment1">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="@string/hello_blank_fragment" />
<Button
android:id="@+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" />
</FrameLayout>
打開navigation.xml,把兩個fragment添加進去,愉快地用箭頭直觀地展示跳轉邏輯
添加左上角的new destination 添加目標界面,然後就可以愉快地玩耍了
通過一句代碼實現跳轉邏輯
通過上面的步驟已經規劃好了,最後需要用代碼來觸發跳轉,例如由Fragment1點擊按鈕跳轉到Fragment2,則我們需要編輯Fragment1的按鈕點擊事件來完成這個邏輯,修改Fragment1的代碼如下
class BlankFragment1 : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_blank1, container, false)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
view.findViewById<Button>(R.id.btn).setOnClickListener {
//實現跳轉
Navigation.findNavController(getView()!!).navigate(R.id.action_blankFragment1_to_blankFragment2)
}
}
}
拓展
總結