Question

我创建了以下包：

主页 - ＆gt; HomeActivity.class，HomeFragment.class，SectionsPageAdapter.class

朋友 - ＆gt; Friends.class

消息 - ＆gt; Messages.class

SectionsPageAdapter扩展FragmentPagerAdapter来管理片段，用 SectionsPageAdapter 编写的代码是：

    package com.example.sk.voiceapplication.HomePage;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

import java.util.ArrayList;
import java.util.List;

public class SectionsPageAdapter extends FragmentPagerAdapter {

    private final List<Fragment> fragment_hierarchy = new ArrayList<>();

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

    @Override
    public Fragment getItem(int position) {
        return fragment_hierarchy.get(position);
    }

    @Override
    public int getCount() {
        return fragment_hierarchy.size();
    }
    public void addFragment(Fragment fragment){
        fragment_hierarchy.add(fragment);
    }
}

Class HomeFragment ：

    package com.example.sk.voiceapplication.HomePage;

import android.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import com.example.sk.voiceapplication.R;


public class HomeFragment extends Fragment {
    private static final String TAG = "HomeFragment";

    private Button btn_test;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.home_fragment,container,false);
        btn_test = (Button) view.findViewById(R.id.button2);
        btn_test.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Toast.makeText(getActivity(),"Testing Button Click 2", Toast.LENGTH_SHORT).show();
            }
        });
        return view;
    }
}

现在，类朋友和消息与HomeFragment相同，但需要进行一些必要的微小更改在课程 HomeActivity 中写道：

    package com.example.sk.voiceapplication.HomePage;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.example.sk.voiceapplication.Friends.Friends;
import com.example.sk.voiceapplication.Messages.Messages;
import com.example.sk.voiceapplication.Profile.MyProfile;
import com.example.sk.voiceapplication.R;

public class HomeActivity extends AppCompatActivity {

    private static final String TAG = "HomeActivity";

    private SectionsPageAdapter sectionsPagerAdapter;
    private ViewPager viewPager;

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

    private void setupFragments() {
        sectionsPagerAdapter = new SectionsPageAdapter(getSupportFragmentManager());
        viewPager = (ViewPager) findViewById(R.id.container);
        setupViewPager(viewPager);
        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);
        tabLayout.getTabAt(0);
        tabLayout.getTabAt(1);
        tabLayout.getTabAt(2);
    }

    private void setupViewPager(ViewPager viewPager) {
        SectionsPageAdapter adapter = new SectionsPageAdapter(getSupportFragmentManager());
        adapter.addFragment(new HomeFragment());
        adapter.addFragment(new Messages());
        adapter.addFragment(new Friends());
        viewPager.setAdapter(adapter);
    }
}

在HomeActivity中创建片段对象并将其添加到带有行的SectionsPageAdapter

adapter.addFragment（new HomeFragment（））;

显示错误：

SectionsPageAdapter中的

addFragment（android.support.v4.app.Fragment）无法应用于（com.example.sk.voiceapplication.HomePage.HomeFragment）

与

类似

adapter.addFragment（new Messages（））;

SectionsPageAdapter中的

addFragment（android.support.v4.app.Fragment）无法应用于（com.example.sk.voiceapplication.Messages.Messages）

adapter.addFragment（new Friends（））;

SectionsPageAdapter中的

addFragment（android.support.v4.app.Fragment）无法应用于（com.example.sk.voiceapplication.Friends.Friends）

我做错了什么？解决方案是什么？

Answer 1

您缺少导入Syntax error, unrecognized expression: mm/dd/yyyy。您必须使用V4片段而不是import android.support.v4.app.Fragment;。

替换 - ：

android.app.Fragment

要 - ：

所有碎片中都有

import android.app.Fragment;。

Answer 2

将此更改为 - ：

public class HomeFragment extends Fragment

{

}

要 - ：

public class HomeFragment extends android.support.v4.app.Fragment

{


}

所有三个条款

如何将片段添加到列表

2 个答案: