Question

我正在尝试使用片段制作带有导航抽屉的应用程序，在主屏幕上应该有图像，并且当您单击图像时，它应该带您到该特定图像的片段，然后视频开始播放。但不幸的是，我在主屏幕上看不到任何图像（也许我在布局上犯了错误）。请帮帮我。预先感谢。

以下代码：-

主要xml文件

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
      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"
      android:id="@+id/drawer_layout"
      android:fitsSystemWindows="true"
      tools:context="com.hangout.google.heedbasketball.MainActivity"
      tools:openDrawer="start"
      tools:deviceIds= "tv"
      tools:ignore="MergeRootFrame">

  <LinearLayout
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:orientation="vertical">



      <android.support.v7.widget.Toolbar
          android:layout_width="match_parent"
          android:layout_height="?attr/actionBarSize"
          android:background="@color/colorPrimaryDark"
          android:id="@+id/toolbar"
          android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
          app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
          android:elevation="4dp"/>

      <ImageView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:id="@+id/i1"
          android:src="@drawable/arena_reaction"/>

      <ImageView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:id="@+id/i2"
          android:src="@drawable/frequentflyer_diop"/>

      <ImageView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:id="@+id/i3"
          android:src="@drawable/frequentflyer_tyus"/>

      <FrameLayout
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/fragement_container" />




  </LinearLayout>

      <android.support.design.widget.NavigationView
          android:layout_width="wrap_content"
          android:layout_height="match_parent"
          android:layout_gravity="start"
          android:id="@+id/nav_view"
          app:headerLayout="@layout/nav_header"
          app:menu="@menu/drawer_menu"/>



  </android.support.v4.widget.DrawerLayout>

主Java文件

package com.hangout.google.heedbasketball;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.MenuItem;

abstract class MainActivity4 extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
    private DrawerLayout drawer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        drawer = findViewById(R.id.drawer_layout);

        NavigationView navigationView = findViewById(R.id.nav_view);
                navigationView.setNavigationItemSelectedListener(this );


        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle
                (this,drawer,toolbar,R.string.navigation_drawer_open,R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();
    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
        switch (menuItem.getItemId()) {

            case R.id.nav_sound:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new SoundFragment()).commit();

                break;

            case R.id.nav_notifications:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new NotificationsFragment()).commit();

                break;

            case R.id.nav_sponsors:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new SponsorsFragment()).commit();

                break;

            case R.id.nav_about:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new AboutFragment()).commit();

                break;

            case R.id.nav_contact_us:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new ContactusFragment()).commit();

                break;

            case R.id.nav_privacy:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new PrivacyFragment()).commit();

                break;

        }

        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    public class SectionPagerAdapter extends FragmentPagerAdapter {

        public SectionPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            Fragment fragment = null;
            switch (position) {
                case 0:
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new FirstFragment()).commit();
                    fragment = new FirstFragment();
                    break;

                    case 1:
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new SecondFragment()).commit();
                    fragment = new SecondFragment();

                case 2:
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragement_container,new ThirdFragment()).commit();
                    fragment = new ThirdFragment();

                    break;

                default:
                    fragment = new FirstFragment();
            }

            return fragment;
        }



        @Override
        public int getCount() {
            return 3;

        }
    }
    public void onBackpressed() {
        if (drawer.isDrawerOpen(GravityCompat.START)){
            drawer.closeDrawer(GravityCompat.START);
        } else {
            onBackPressed();
        }


    }
}

这也是我为其他视频定义的一个视频的Java片段

package com.hangout.google.heedbasketball;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.VideoView;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link FirstFragment.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link FirstFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class FirstFragment extends Fragment {
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    private OnFragmentInteractionListener mListener;

    public FirstFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment FirstFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static FirstFragment newInstance(String param1, String param2) {
        FirstFragment fragment = new FirstFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

//My video code here
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            VideoView v1 = (VideoView) findViewById(R.id.v1);
            v1.setVideoURI(Uri.parse("https://myvideo.mp4"));
            v1.start();
            v1.requestFocus();
            v1.setKeepScreenOn(true);


        }
    }

    private Object findViewById(int v1) {
        return 0;
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_first, container, false);

    }

    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString() + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }


        }

xml file fragment for the video

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".FirstFragment"
    android:background="@color/colorPrimaryDark">

    <!-- TODO: Update blank fragment layout -->

<VideoView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/v1" />

</RelativeLayout>

Answer 1

您已经在create上创建了findViewById函数，该函数返回0。

您需要从正在排版的布局中获取视频参考。与此类似。

 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, 
                          Bundle savedInstanceState) {
    // Inflate the layout for this fragment
     View view  =  inflater.inflate(R.layout.fragment_first, container, false);
        // see the difference
        VideoView v1 = (VideoView) view.findViewById(R.id.v1);
        v1.setVideoURI(Uri.parse("https://myvideo.mp4"));
        v1.start();
        v1.requestFocus();
        v1.setKeepScreenOn(true);    
     return view;
}

使用片段将Imageview转换为VideoView

1 个答案: