java - Android fragment 类型不匹配

Question

我是 Android 新手，正在学习达特茅斯的教程。 http://www.cs.dartmouth.edu/~campbell/cs65/lecture08/lecture08.html

我正在关注 MainActivity.java 中的所有代码，

// create the fragments
Fragment mFindFragment = new FindFragment();
Fragment mChatFragment = new ChatFragment();

// bind the fragments to the tabs - set up tabListeners for each tab 
mFindTab.setTabListener(new MyTabsListener(mFindFragment,
                           getApplicationContext()));
mChatTab.setTabListener(new MyTabsListener(mChatFragment,
                           getApplicationContext()));

我遇到了此错误:类型不匹配:无法从 FindFragment 转换为 Fragment。所以我按照修复错误建议并将代码更改为

// create the fragments
FindFragment mFindFragment = new FindFragment();

// bind the fragments to the tabs - set up tabListeners for each tab 
mFindTab.setTabListener(new MyTabsListener(mFindFragment,
                           getApplicationContext()));

现在，出现了一个新错误:构造函数 MyTabsListener(FindFragment, Context) 未定义。

以防万一导入很重要，它们在这里:

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.content.Context;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

对于 myTabsListener:

  class MyTabsListener implements ActionBar.TabListener {
    public Fragment fragment;
    public Context context;

    public MyTabsListener(Fragment fragment, Context context) {
        this.fragment = fragment;
        this.context = context;

    }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        Toast.makeText(context, "Reselected!", Toast.LENGTH_SHORT).show();

    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        Toast.makeText(context, "Selected!", Toast.LENGTH_SHORT).show();
        ft.replace(R.id.container, fragment);
    }

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        Toast.makeText(context, "Unselected!", Toast.LENGTH_SHORT).show();
        ft.remove(fragment);
    }

}

对于我的 FindFragment 类:

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class FindFragment extends Fragment {
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.findfragment, container, false);
    }


}

我在这里很困惑。我不确定这是否与我的导入、库设置或其他问题有关。提前致谢!

Answer 1

您需要更改此设置

import android.support.v4.app.Fragment;
// you will use this import when you want fragment from support library 
// in that case you will extend FragmentActivity which is the base class for support based fragments

至

import android.app.Fragment;

在FindFragment.java中。

在 ChatFragment.java 中也进行同样的操作