android - 未附加 ViewPager 和 Fragment

Question

我正在尝试使用 fragment 实现选项卡 View ，但我的 fragment 没有出现。我已经将它与 viewpager 链接起来了。但仍然没有用。

这是我的 MainActivity

package com.example.minkhantlu.timetableapp;
import android.support.design.widget.TabLayout;
import android.support.v4.content.ContextCompat;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.widget.TableLayout;

import com.example.minkhantlu.timetableapp.fragment.ViewPagerAdapter;

public class HomeActivity extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
private ViewPagerAdapter viewAdapter;

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

    tabLayout = (TabLayout) findViewById(R.id.tab_layout);
    viewPager = (ViewPager) findViewById(R.id.my_view_pager);

    viewAdapter = new ViewPagerAdapter(getSupportFragmentManager());
    viewPager.setAdapter(viewAdapter);

    TabLayout.Tab mon = tabLayout.newTab();
    TabLayout.Tab tue = tabLayout.newTab();
    TabLayout.Tab wed = tabLayout.newTab();
    TabLayout.Tab thur = tabLayout.newTab();
    TabLayout.Tab fri = tabLayout.newTab();

    mon.setText("Mon");
    tue.setText("Tue");
    wed.setText("Wed");
    thur.setText("Thur");
    fri.setText("Fri");

    tabLayout.addTab(mon, 0);
    tabLayout.addTab(tue, 1);
    tabLayout.addTab(wed, 2);
    tabLayout.addTab(thur,3);
    tabLayout.addTab(fri,4);

    tabLayout.setTabTextColors(ContextCompat.getColorStateList(this,    R.color.colorAccent));

    tabLayout.setSelectedTabIndicatorColor(ContextCompat.getColor(this, R.color.colorAccent));

    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
}

尝试使用此 viewPagerAdapter

package com.example.minkhantlu.timetableapp.fragment;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.util.Log;

public class ViewPagerAdapter extends FragmentPagerAdapter {


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

@Override
public Fragment getItem(int position) {
    return new MondayFragment();
}

@Override
public int getCount() {
    return 0;
}

我的 fragment

package com.example.minkhantlu.timetableapp.fragment;

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

import com.example.minkhantlu.timetableapp.R;

public class MondayFragment extends Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    return inflater.inflate(R.layout.fragment_monday, container, false);
}

} fragment xml

<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="com.example.minkhantlu.timetableapp.fragment.MondayFragment">

<!-- TODO: Update blank fragment layout -->
<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:text="@string/hello_blank_fragment" />

</RelativeLayout>

activity_main.xml

<?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="com.example.minkhantlu.timetableapp.HomeActivity">
<android.support.design.widget.TabLayout
    android:id="@+id/tab_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimaryDark"/>

<android.support.v4.view.ViewPager
    android:id="@+id/my_view_pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@+id/tab_layout"
    />
</FrameLayout>

但是我的 fragment 没有出现，请帮助我。

Answer 1

在 ViewPagerAdapter 中，你可以尝试改变

@Override
public int getCount() {
    return 0;
}

到

@Override
public int getCount() {
    return 1;
}