选项卡侦听器中的混合片段类型

Question

我有一个基于谷歌提供的文档代码和sherlock操作栏类的选项卡侦听器。

我想让我的两个选项卡使用ListFragment类，一个选项卡使用自定义GridFragment类别。

然而，选项卡侦听器一次只能排除一个类型，我是否只需要创建一个标准片段并在其中放入列表视图或网格视图？还是我需要为每个创建一个单独的选项卡侦听器？或者，选项卡侦听器有没有一种方法可以排除任何类型的片段、标准、列表或网格，只要它继承自片段类。

package com.NYXDigital.LookBunnyFind;
import android.app.Activity;
import android.support.v4.app.FragmentTransaction;
import com.actionbarsherlock.app.ActionBar;
import com.actionbarsherlock.app.ActionBar.Tab;
import com.actionbarsherlock.app.SherlockFragment;

public class TabListener<T extends SherlockFragment> implements ActionBar.TabListener {
    private SherlockFragment mFragment;
    private final Activity mActivity;
    private final String mTag;
    private final Class<T> mClass;
    /** Constructor used each time a new tab is created.
      * @param activity  The host Activity, used to instantiate the fragment
      * @param tag  The identifier tag for the fragment
      * @param clz  The fragment's Class, used to instantiate the fragment
      */
    public TabListener(Activity activity, String tag, Class<T> clz) {
        mActivity = activity;
        mTag = tag;
        mClass = clz;
    }
    /* The following are each of the ActionBar.TabListener callbacks */
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // Check if the fragment is already initialized
        if (mFragment == null) {
            // If not, instantiate and add it to the activity
            mFragment = (SherlockFragment)SherlockFragment.instantiate(mActivity, mClass.getName());
            ft.add(android.R.id.content, mFragment, mTag);
        } else {
            // If it exists, simply attach it in order to show it
            ft.attach(mFragment);
        }
    }
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        if (mFragment != null) {
            // Detach the fragment, because another one is being attached
            ft.detach(mFragment);
        }
    }
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // User selected the already selected tab. Usually do nothing.
    }
}

Answer 1

我最终创建了一个通用的片段项类，TabListener接受该类作为其参数。这个类排除了一个片段类，并为您自动创建它。

下面的代码是一个类，它将包含您想要添加的每个片段类以及一个标题。添加到选项卡侦听器的每个片段都需要一个。

package com.NYXDigital.LookBunnyFind.Widget;
import android.support.v4.app.Fragment;
public class FragmentViewPagerItem {
    private String title;
    private Class<? extends Fragment> fragmentClass;
    public FragmentViewPagerItem(String title, Class<? extends Fragment> fragmentClass){
        this.title = title;
        this.setFragmentClass(fragmentClass);
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public Class<? extends Fragment> getFragmentClass() {
        return fragmentClass;
    }
    public void setFragmentClass(Class<? extends Fragment> fragmentClass) {
        this.fragmentClass = fragmentClass;
    }
    public Fragment newInstanceOfFragmentClass() throws InstantiationException, IllegalAccessException{
        return this.fragmentClass.newInstance();
    }
}

这个适配器被修改为接受之上的FragmentViewPagerItemClass的数组

import java.util.ArrayList;
import java.util.List;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import com.NYXDigital.LookBunnyFind.Widget.FragmentViewPagerItem;
public class FragmentViewPagerAdapter extends FragmentPagerAdapter {
    private List<FragmentViewPagerItem> mFragments = new ArrayList<FragmentViewPagerItem>();
    public FragmentViewPagerAdapter(FragmentManager fm) {
        super(fm);
    }
    public void addFragment(FragmentViewPagerItem fragment) {
        if (mFragments == null) {
            mFragments = new ArrayList<FragmentViewPagerItem>();
        }
        mFragments.add(fragment);
        notifyDataSetChanged();
    }
    public Fragment getItem(int position) {
        Fragment fragment = null;
        try {
            fragment = mFragments.get(position % mFragments.size())
                    .newInstanceOfFragmentClass();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return fragment;
    }
    public int getCount() {
        return mFragments.size();
    }
    public CharSequence getPageTitle(int position) {
        return mFragments.get(position % mFragments.size()).getTitle()
                .toUpperCase();
    }
}

因此，为了使用这些类，您需要为每个Fragment创建一个FragmentViewPagerItem，并为您的Fragment传递一个标题和类。然后使用addFragment方法将其添加到适配器中，就像通常一样。然后将其设置为ViewPager的适配器，并绑定标题指示器以查看标题。

// Create adapter for pager and add fragments to be displayed
FragmentViewPagerAdapter adapter = new FragmentViewPagerAdapter(
        getSupportFragmentManager());
// Local
FragmentViewPagerItem localFragment = new FragmentViewPagerItem(
        "Local", BranchListFragment.class);
adapter.addFragment(localFragment);
// Find
FragmentViewPagerItem findFragment = new FragmentViewPagerItem("Find",
        FindFragment.class);
adapter.addFragment(findFragment);
// Events
FragmentViewPagerItem eventsFragment = new FragmentViewPagerItem(
        "Events", EventListFragment.class);
adapter.addFragment(eventsFragment);
// Set the pager with an adapter
ViewPager pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Bind the title indicator to the adapter
TabPageIndicator mIndicator = (TabPageIndicator) findViewById(R.id.indicator);
mIndicator.setViewPager(pager);

我正在考虑开源，你们怎么看？