问题描述

Fragment tab 内容不能显示

我使用俩个 fragments 创建了程序。这俩个 fragment 可以互相切换。代码编译和运行都没有问题，俩个 tabs 都能显示出来，也可以互相切换，但是 tabs 没有内容。我觉得是 fragments 的问题，然后设置 setcontentview。为什么 HoloEverywhere 和ActionbarSherlock 里 tab 的内容显示不出来？

main activity：

import java.util.ArrayList;

import org.holoeverywhere.app.Activity;
import org.holoeverywhere.widget.TextView;
import com.actionbarsherlock.app.ActionBar;
import com.actionbarsherlock.app.ActionBar.Tab;
import com.actionbarsherlock.app.SherlockActivity;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.view.WindowManager;

public class SwipeTabsMainActivity extends Activity {
ViewPager mViewPager;
TabsAdapter mTabsAdapter;
TextView tabCenter;
TextView tabText;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);

    mViewPager = new ViewPager(this);
    mViewPager.setId(R.id.pager);

    setContentView(mViewPager);
    ActionBar bar = getSupportActionBar();
    bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);

    mTabsAdapter = new TabsAdapter(this, mViewPager);

        mTabsAdapter.addTab(bar.newTab().setText("Stopwatch"),StopWatchFragment.class, null);
    mTabsAdapter.addTab(bar.newTab().setText("Timer"), CountdownFragment.class, null);
}
public static class TabsAdapter extends FragmentPagerAdapter implements
        ActionBar.TabListener, ViewPager.OnPageChangeListener {
    private final Context mContext;
    private final ActionBar mActionBar;
    private final ViewPager mViewPager;
    private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();

    static final class TabInfo {
        private final Class<?> clss;
        private final Bundle args;

        TabInfo(Class<?> _class, Bundle _args) {
            clss = _class;
            args = _args;
        }
    }
    public TabsAdapter(Activity activity, ViewPager pager) {
        super(activity.getSupportFragmentManager());
        mContext = activity;
        mActionBar = activity.getSupportActionBar();
        mViewPager = pager;
        mViewPager.setAdapter(this);
        mViewPager.setOnPageChangeListener(this);
    }
    public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
        TabInfo info = new TabInfo(clss, args);
        tab.setTag(info);
        tab.setTabListener(this);
        mTabs.add(info);
        mActionBar.addTab(tab);
        notifyDataSetChanged();
    }
    @Override
    public int getCount() {
        return mTabs.size();
    }
    @Override
    public Fragment getItem(int position) {
        TabInfo info = mTabs.get(position);
        return Fragment.instantiate(mContext, info.clss.getName(),
                info.args);
    }
    @Override
    public void onPageScrolled(int position, float positionOffset,
            int positionOffsetPixels) {
    }
    @Override
    public void onPageSelected(int position) {
        mActionBar.setSelectedNavigationItem(position);
    }
    @Override
    public void onPageScrollStateChanged(int state) {
    }
    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        Object tag = tab.getTag();
        for (int i = 0; i < mTabs.size(); i++) {
            if (mTabs.get(i) == tag) {
                mViewPager.setCurrentItem(i);
            }
        }
    }
    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    }
    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
    }
}
}

Main Activity's xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager  xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pager"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="1" />