Question

我的Android应用程序遇到了问题。当我添加两个标签时，我也有两个片段。但问题是两个标签上都出现了相同的片段。另一个片段没有显示出来。这是它的样子。

以下是我的活动代码：

public class DatabaseFiller extends Activity{
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();

    StrictMode.setThreadPolicy(policy);


    setContentView(R.layout.rmactivity);

    ActionBar actionBar = getActionBar();
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    actionBar.setSubtitle("Created by Rohit Nandakumar");

    /*ActionBar.Tab searchdb = actionBar.newTab().setText("Search Database");
    ActionBar.Tab searchlist = actionBar.newTab().setText("Show List"); */

    ActionBar.Tab Frag1 = actionBar.newTab().setText("Search Database");
    ActionBar.Tab Frag2 = actionBar.newTab().setText("Show List");

    Fragment fragment1 = new DatabaseFillerFragment();
    Fragment fragment2 = new DeleteDBItems();

    Frag1.setTabListener(new MyTabListener(fragment1));
    Frag2.setTabListener(new MyTabListener(fragment2));

    actionBar.addTab(Frag1);
    actionBar.addTab(Frag2);

}
}

这是我的整个MyTabListener类：

package com.example.foodsaver2;

import android.app.ActionBar.Tab;
import android.app.ActionBar.TabListener; 
import android.app.ActionBar;
import android.app.Fragment;
import android.app.FragmentTransaction;

public class MyTabListener implements TabListener {

public Fragment fragment;

public MyTabListener(Fragment fragment) {
    this.fragment = fragment;
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
    if (fragment == null) {
        // If not, instantiate and add it to the activity
        ft.add(android.R.id.content, fragment);
    } else {
        // If it exists, simply attach it in order to show it
        ft.attach(fragment);
    }
}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
    if (fragment != null) {
        // Detach the fragment, because another one is being attached
        ft.detach(fragment);
    }
}

}

我在这里做错了什么？关于这个问题的任何帮助将不胜感激。

Answer 1

初始化侦听器，分离片段并提交它。

选中选项卡只需添加其他分段。

请参阅以下修订代码以获取帮助 -

public MyTabListener(Activity activity, String tag, Class<T> cls, Bundle args) {
                mActivity = activity;
                mTag = tag;
                mClass = cls;
                mArgs = args;

            fragment  = mActivity.getFragmentManager().findFragmentByTag(mTag);
            if (fragment  != null) {
                FragmentTransaction ft = mActivity.getFragmentManager().beginTransaction();
                ft.detach(fragment);
                ft.commit();
            }
    }


    public void onTabSelected(Tab tab, FragmentTransaction ft) {
                fragment  = Fragment.instantiate(mActivity, mClass.getName(), mArgs);
                ft.add(android.R.id.content, fragment , mTag);
        }

        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
            if (fragment != null) {
                ft.detach(fragment);
            }
        }

Answer 2

您需要在FragmentTransaction上调用commit方法来触发事务发生。

所有选项卡中都会显示相同的片段

2 个答案: