导航在点击时未跳转到下一个片段。

huangapple
go评论112阅读模式
英文:

Navigation doesnt proceed to next fragment on click

问题

在按钮点击时，奇怪的是它不转到其他片段。

activity_main.xml：

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     xmlns:app="http://schemas.android.com/apk/res-auto"
  4.     xmlns:tools="http://schemas.android.com/tools"
  5.     android:layout_width="match_parent"
  6.     android:layout_height="match_parent"
  7.     tools:context=".MainActivity">
  9.     <LinearLayout
  10.         android:layout_width="match_parent"
  11.         android:layout_height="match_parent"
  12.         android:orientation="vertical">
  14.         <androidx.appcompat.widget.Toolbar
  15.             android:id="@+id/toolbar"
  16.             android:layout_width="match_parent"
  17.             android:layout_height="wrap_content"
  18.             android:background="?attr/colorPrimary"
  19.             android:minHeight="?attr/actionBarSize"
  20.             android:theme="?attr/actionBarTheme"
  21.             app:logo="@android:drawable/btn_star_big_on" />
  23.         <fragment
  24.             android:id="@+id/fragment"
  25.             android:name="androidx.navigation.fragment.NavHostFragment"
  26.             android:layout_width="match_parent"
  27.             android:layout_height="match_parent"
  28.             app:defaultNavHost="true"
  29.             app:navGraph="@navigation/main_nav" />
  31.     </LinearLayout>
  33. </androidx.constraintlayout.widget.ConstraintLayout>

fragment_first.xml：

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     xmlns:app="http://schemas.android.com/apk/res-auto"
  4.     xmlns:tools="http://schemas.android.com/tools"
  5.     android:layout_width="match_parent"
  6.     android:layout_height="match_parent"
  7.     android:background="@color/colorPrimary"
  8.     android:elevation="20dp"
  9.     tools:context=".first">
  11.     <Button
  12.         android:id="@+id/button_first"
  13.         android:layout_width="wrap_content"
  14.         android:layout_height="wrap_content"
  15.         android:elevation="20dp"
  16.         android:text="First"
  17.         android:textColor="@color/colorPrimary"
  18.         android:textStyle="bold"
  19.         app:layout_constraintBottom_toBottomOf="parent"
  20.         app:layout_constraintEnd_toEndOf="parent"
  21.         app:layout_constraintHorizontal_bias="0.5"
  22.         app:layout_constraintStart_toStartOf="parent"
  23.         app:layout_constraintTop_toTopOf="parent" />
  24. </androidx.constraintlayout.widget.ConstraintLayout>

fragment_second.xml：

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     xmlns:app="http://schemas.android.com/apk/res-auto"
  4.     xmlns:tools="http://schemas.android.com/tools"
  5.     android:layout_width="match_parent"
  6.     android:layout_height="match_parent"
  7.     android:background="#C13584"
  8.     tools:context=".second">
  10.     <Button
  11.         android:id="@+id/button2"
  12.         android:layout_width="wrap_content"
  13.         android:layout_height="wrap_content"
  14.         android:text="Second"
  15.         android:textColor="#C13584"
  16.         android:textStyle="bold"
  17.         app:layout_constraintBottom_toBottomOf="parent"
  18.         app:layout_constraintEnd_toEndOf="parent"
  19.         app:layout_constraintHorizontal_bias="0.5"
  20.         app:layout_constraintStart_toStartOf="parent"
  21.         app:layout_constraintTop_toTopOf="parent" />
  22. </androidx.constraintlayout.widget.ConstraintLayout>

main_nav.xml：

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <navigation xmlns:android="http://schemas.android.com/apk/res/android"
  3.     xmlns:app="http://schemas.android.com/apk/res-auto"
  4.     xmlns:tools="http://schemas.android.com/tools"
  5.     android:id="@+id/main_nav"
  6.     app:startDestination="@id/first">
  8.     <fragment
  9.         android:id="@+id/first"
  10.         android:name="com.example.fragments.first"
  11.         android:label="fragment_first"
  12.         tools:layout="@layout/fragment_first">
  13.         <action
  14.             android:id="@+id/navigateToSecondFragment"
  15.             app:destination="@id/second" />
  16.     </fragment>
  17.     <fragment
  18.         android:id="@+id/second"
  19.         android:name="com.example.fragments.second"
  20.         android:label="fragment_second"
  21.         tools:layout="@layout/fragment_second">
  22.         <action
  23.             android:id="@+id/navigateToFirstFragment"
  24.             app:destination="@id/first" />
  25.     </fragment>
  26. </navigation>

first.java：

  1. package com.example.fragments;
  3. import android.os.Bundle;
  5. import androidx.fragment.app.Fragment;
  6. import androidx.navigation.Navigation;
  8. import android.util.Log;
  9. import android.view.LayoutInflater;
  10. import android.view.View;
  11. import android.view.ViewGroup;
  12. import android.widget.Button;
  14. public class first extends Fragment {
  16.     private static final String ARG_PARAM1 = "param1";
  17.     private static final String ARG_PARAM2 = "param2";
  19.     private String mParam1;
  20.     private String mParam2;
  22.     private Button button;
  24.     public first() {
  25.         // Required empty public constructor
  26.     }
  28.     public static first newInstance(String param1, String param2) {
  29.         first fragment = new first();
  30.         Bundle args = new Bundle();
  31.         args.putString(ARG_PARAM1, param1);
  32.         args.putString(ARG_PARAM2, param2);
  33.         fragment.setArguments(args);
  34.         return fragment;
  35.     }
  37.     @Override
  38.     public void onCreate(Bundle savedInstanceState) {
  39.         super.onCreate(savedInstanceState);
  40.         if (getArguments() != null) {
  41.             mParam1 = getArguments().getString(ARG_PARAM1);
  42.             mParam2 = getArguments().getString(ARG_PARAM2);
  43.         }
  44.     }
  46.     @Override
  47.     public View onCreateView(LayoutInflater inflater, ViewGroup container,
  48.                              Bundle savedInstanceState) {
  49.         View view = inflater.inflate(R.layout.fragment_first, container, false);
  51.         button = (Button) view.findViewById(R.id.button_first);
  53.         button.setOnClickListener(new View.OnClickListener() {
  54.             @Override
  55.             public void onClick(View view) {
  56.                 Navigation.findNavController(view).navigate(R.id.navigateToSecondFragment);
  57.             }
  58.         });
  60.         return view;
  61.     }
  62. }

second.java：

  1. package com.example.fragments;
  3. import android.os.Bundle;
  5. import androidx.fragment.app.Fragment;
  6. import androidx.navigation.Navigation;
  8. import android.view.LayoutInflater;
  9. import android.view.View;
  10. import android.view.ViewGroup;
  11. import android.widget.Button;
  13. public class second extends Fragment {
  15.     private static final String ARG_PARAM1 = "param1";
  16.     private static final String ARG_PARAM2 = "param2";
  18.     private String mParam1;
  19.     private String mParam2;
  21.     private Button button;
  23.     public second() {
  24.         // Required empty public constructor
  25.     }
  27.     public static second newInstance(String param1, String param2) {
  28.         second fragment = new second();
  29.         Bundle args = new Bundle();
  30.         args.putString(ARG_PARAM1, param1);
  31.         args.putString(ARG_PARAM2, param2);
  32.         fragment.setArguments(args);
  33.         return fragment;
  34.     }
  36.     @Override
  37.     public void onCreate(Bundle savedInstanceState) {
  38.         super.onCreate(savedInstanceState);
  39.         if (getArguments() != null) {
  40.             mParam1 = getArguments().getString(ARG_PARAM
  42. <details>
  43. <summary>英文:</summary>
  45. As the title describes on button click it doesnt go to the other fragment for some odd reason.
  47. activity_main.xml:
  49.     &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  50.     &lt;androidx.constraintlayout.widget.ConstraintLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  51.         xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  52.         xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  53.         android:layout_width=&quot;match_parent&quot;
  54.         android:layout_height=&quot;match_parent&quot;
  55.         tools:context=&quot;.MainActivity&quot;&gt;
  56.     
  57.         &lt;LinearLayout
  58.             android:layout_width=&quot;match_parent&quot;
  59.             android:layout_height=&quot;match_parent&quot;
  60.             android:orientation=&quot;vertical&quot;&gt;
  61.     
  62.             &lt;androidx.appcompat.widget.Toolbar
  63.                 android:id=&quot;@+id/toolbar&quot;
  64.                 android:layout_width=&quot;match_parent&quot;
  65.                 android:layout_height=&quot;wrap_content&quot;
  66.                 android:background=&quot;?attr/colorPrimary&quot;
  67.                 android:minHeight=&quot;?attr/actionBarSize&quot;
  68.                 android:theme=&quot;?attr/actionBarTheme&quot;
  69.                 app:logo=&quot;@android:drawable/btn_star_big_on&quot; /&gt;
  70.     
  71.             &lt;fragment
  72.                 android:id=&quot;@+id/fragment&quot;
  73.                 android:name=&quot;androidx.navigation.fragment.NavHostFragment&quot;
  74.                 android:layout_width=&quot;match_parent&quot;
  75.                 android:layout_height=&quot;match_parent&quot;
  76.                 app:defaultNavHost=&quot;true&quot;
  77.                 app:navGraph=&quot;@navigation/main_nav&quot; /&gt;
  78.     
  79.         &lt;/LinearLayout&gt;
  80.     
  81.     &lt;/androidx.constraintlayout.widget.ConstraintLayout&gt;
  83. fragment_first.xml:
  85.     &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  86.     &lt;androidx.constraintlayout.widget.ConstraintLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  87.         xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  88.         xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  89.         android:layout_width=&quot;match_parent&quot;
  90.         android:layout_height=&quot;match_parent&quot;
  91.         android:background=&quot;@color/colorPrimary&quot;
  92.         android:elevation=&quot;20dp&quot;
  93.         tools:context=&quot;.first&quot;&gt;
  94.     
  95.         &lt;Button
  96.             android:id=&quot;@+id/button_first&quot;
  97.             android:layout_width=&quot;wrap_content&quot;
  98.             android:layout_height=&quot;wrap_content&quot;
  99.             android:elevation=&quot;20dp&quot;
  100.             android:text=&quot;First&quot;
  101.             android:textColor=&quot;@color/colorPrimary&quot;
  102.             android:textStyle=&quot;bold&quot;
  103.             app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
  104.             app:layout_constraintEnd_toEndOf=&quot;parent&quot;
  105.             app:layout_constraintHorizontal_bias=&quot;0.5&quot;
  106.             app:layout_constraintStart_toStartOf=&quot;parent&quot;
  107.             app:layout_constraintTop_toTopOf=&quot;parent&quot; /&gt;
  108.     &lt;/androidx.constraintlayout.widget.ConstraintLayout&gt;
  110. fragment_second.xml:
  112.     &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  113.     &lt;androidx.constraintlayout.widget.ConstraintLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  114.         xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  115.         xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  116.         android:layout_width=&quot;match_parent&quot;
  117.         android:layout_height=&quot;match_parent&quot;
  118.         android:background=&quot;#C13584&quot;
  119.         tools:context=&quot;.second&quot;&gt;
  120.     
  121.         &lt;Button
  122.             android:id=&quot;@+id/button2&quot;
  123.             android:layout_width=&quot;wrap_content&quot;
  124.             android:layout_height=&quot;wrap_content&quot;
  125.             android:text=&quot;Second&quot;
  126.             android:textColor=&quot;#C13584&quot;
  127.             android:textStyle=&quot;bold&quot;
  128.             app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
  129.             app:layout_constraintEnd_toEndOf=&quot;parent&quot;
  130.             app:layout_constraintHorizontal_bias=&quot;0.5&quot;
  131.             app:layout_constraintStart_toStartOf=&quot;parent&quot;
  132.             app:layout_constraintTop_toTopOf=&quot;parent&quot; /&gt;
  133.     &lt;/androidx.constraintlayout.widget.ConstraintLayout&gt;
  135. main_nav.xml:
  137.     &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  138.     &lt;navigation xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  139.         xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  140.         xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  141.         android:id=&quot;@+id/main_nav&quot;
  142.         app:startDestination=&quot;@id/first&quot;&gt;
  143.     
  144.         &lt;fragment
  145.             android:id=&quot;@+id/first&quot;
  146.             android:name=&quot;com.example.fragments.first&quot;
  147.             android:label=&quot;fragment_first&quot;
  148.             tools:layout=&quot;@layout/fragment_first&quot; &gt;
  149.             &lt;action
  150.                 android:id=&quot;@+id/navigateToSecondFragment&quot;
  151.                 app:destination=&quot;@id/second&quot; /&gt;
  152.     
  153.         &lt;/fragment&gt;
  154.         &lt;fragment
  155.             android:id=&quot;@+id/second&quot;
  156.             android:name=&quot;com.example.fragments.second&quot;
  157.             android:label=&quot;fragment_second&quot;
  158.             tools:layout=&quot;@layout/fragment_second&quot; &gt;
  159.             &lt;action
  160.                 android:id=&quot;@+id/navigateToFirstFragment&quot;
  161.                 app:destination=&quot;@id/first&quot; /&gt;
  162.         &lt;/fragment&gt;
  163.     &lt;/navigation&gt;
  165. first.java:
  167.     package com.example.fragments;
  168.     
  169.     import android.os.Bundle;
  170.     
  171.     import androidx.fragment.app.Fragment;
  172.     import androidx.navigation.Navigation;
  173.     
  174.     import android.util.Log;
  175.     import android.view.LayoutInflater;
  176.     import android.view.View;
  177.     import android.view.ViewGroup;
  178.     import android.widget.Button;
  179.     
  180.     /**
  181.      * A simple {@link Fragment} subclass.
  182.      * Use the {@link first#newInstance} factory method to
  183.      * create an instance of this fragment.
  184.      */
  185.     public class first extends Fragment {
  186.     
  187.         // TODO: Rename parameter arguments, choose names that match
  188.         // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
  189.         private static final String ARG_PARAM1 = &quot;param1&quot;;
  190.         private static final String ARG_PARAM2 = &quot;param2&quot;;
  191.     
  192.         // TODO: Rename and change types of parameters
  193.         private String mParam1;
  194.         private String mParam2;
  195.     
  196.         private Button button;
  197.     
  198.         public first() {
  199.             // Required empty public constructor
  200.         }
  201.     
  202.         /**
  203.          * Use this factory method to create a new instance of
  204.          * this fragment using the provided parameters.
  205.          *
  206.          * @param param1 Parameter 1.
  207.          * @param param2 Parameter 2.
  208.          * @return A new instance of fragment first.
  209.          */
  210.         // TODO: Rename and change types and number of parameters
  211.         public static first newInstance(String param1, String param2) {
  212.             first fragment = new first();
  213.             Bundle args = new Bundle();
  214.             args.putString(ARG_PARAM1, param1);
  215.             args.putString(ARG_PARAM2, param2);
  216.             fragment.setArguments(args);
  217.             return fragment;
  218.         }
  219.     
  220.         @Override
  221.         public void onCreate(Bundle savedInstanceState) {
  222.             super.onCreate(savedInstanceState);
  223.             if (getArguments() != null) {
  224.                 mParam1 = getArguments().getString(ARG_PARAM1);
  225.                 mParam2 = getArguments().getString(ARG_PARAM2);
  226.             }
  227.         }
  228.     
  229.         @Override
  230.         public View onCreateView(LayoutInflater inflater, ViewGroup container,
  231.                                  Bundle savedInstanceState) {
  232.             // Inflate the layout for this fragment
  233.     
  234.             View view =  inflater.inflate(R.layout.fragment_first, container, false);
  235.     
  236.             button = (Button) view.findViewById(R.id.button_first);
  237.     
  238.             button.setOnClickListener(new View.OnClickListener(){
  239.                 @Override
  240.                 public void onClick(View view) {
  241.                     //Start second view
  242.                     //Navigation.findNavController(view).navigate(R.id.);
  243.                     Navigation.findNavController(view).navigate(R.id.navigateToSecondFragment);
  244.     
  245.                 }
  246.             });
  247.     
  248.     
  249.             return view;
  250.         }
  251.     }
  253. second.java:
  255.     package com.example.fragments;
  256.     
  257.     import android.os.Bundle;
  258.     
  259.     import androidx.fragment.app.Fragment;
  260.     import androidx.navigation.Navigation;
  261.     
  262.     import android.view.LayoutInflater;
  263.     import android.view.View;
  264.     import android.view.ViewGroup;
  265.     import android.widget.Button;
  266.     
  267.     /**
  268.      * A simple {@link Fragment} subclass.
  269.      * Use the {@link second#newInstance} factory method to
  270.      * create an instance of this fragment.
  271.      */
  272.     public class second extends Fragment {
  273.     
  274.         // TODO: Rename parameter arguments, choose names that match
  275.         // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
  276.         private static final String ARG_PARAM1 = &quot;param1&quot;;
  277.         private static final String ARG_PARAM2 = &quot;param2&quot;;
  278.     
  279.         // TODO: Rename and change types of parameters
  280.         private String mParam1;
  281.         private String mParam2;
  282.     
  283.         private Button button;
  284.     
  285.         public second() {
  286.             // Required empty public constructor
  287.         }
  288.     
  289.         /**
  290.          * Use this factory method to create a new instance of
  291.          * this fragment using the provided parameters.
  292.          *
  293.          * @param param1 Parameter 1.
  294.          * @param param2 Parameter 2.
  295.          * @return A new instance of fragment second.
  296.          */
  297.         // TODO: Rename and change types and number of parameters
  298.         public static second newInstance(String param1, String param2) {
  299.             second fragment = new second();
  300.             Bundle args = new Bundle();
  301.             args.putString(ARG_PARAM1, param1);
  302.             args.putString(ARG_PARAM2, param2);
  303.             fragment.setArguments(args);
  304.             return fragment;
  305.         }
  306.     
  307.         @Override
  308.         public void onCreate(Bundle savedInstanceState) {
  309.             super.onCreate(savedInstanceState);
  310.             if (getArguments() != null) {
  311.                 mParam1 = getArguments().getString(ARG_PARAM1);
  312.                 mParam2 = getArguments().getString(ARG_PARAM2);
  313.             }
  314.         }
  315.     
  316.         @Override
  317.         public View onCreateView(LayoutInflater inflater, ViewGroup container,
  318.                                  Bundle savedInstanceState) {
  319.             // Inflate the layout for this fragment
  320.             View view =  inflater.inflate(R.layout.fragment_first, container, false);
  321.     
  322.             button = (Button) view.findViewById(R.id.button_first);
  323.             button.setOnClickListener(new View.OnClickListener(){
  324.                 @Override
  325.                 public void onClick(View view) {
  326.                     //Start first view
  327.                     Navigation.findNavController(view).navigate(R.id.navigateToFirstFragment);
  328.                 }
  329.             });
  330.             return view;
  331.         }
  332.     }
  334. </details>
  337. # 答案1
  338. **得分**: 1
  340. 对于您的“第二个”片段，您正在填充用于“第一个”片段的布局，即`R.layout.fragment_first`。您的导航可能实际上运行良好（我没有发现任何问题），只是两个片段的布局相同，因此您不会注意到转换，因为没有定义转换动画。检查当您点击按钮时是否导航栏的标题会更改（从“fragment_first”到“fragment_second”，如标签中所定义的那样），如果是，则问题不在于导航。
  342. <details>
  343. <summary>英文:</summary>
  345. For your `second` fragment, you are inflating layout that is meant to be for the `first` fragment, i.e. `R.layout.fragment_first`. Your navigation may actually be working fine (I did not find any issue), it is just that the layout for both fragments are the same, so you would not notice the transition, as no transition animations were defined. Check if the navigationBar&#39;s title changes when you click the button (from `fragment_first` to `fragment_second`, as defined by the labels), if yes, then the issue is not in navigation.
  347. </details>

huangapple
  • 本文由 发表于 2020年8月18日 14:32:49
  • 转载请务必保留本文链接：https://go.coder-hub.com/63463038.html
  • android
  • android-fragments
  • java
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定