Question

几天来，我一直在努力用新的数据列表更新ArrayAdaptor中的ListView数据，但它无法正常工作。我已经在堆栈溢出上搜索了很多关于此的主题，但我的问题仍然存在。我已经尝试过listAdapter.notifyDataSetChanged（）;方法，但什么也没发生。我在这里发布我的代码，请帮助我。感谢

这是MyTabActivity.java

@SuppressLint("NewApi")
public class MyTabActivity extends FragmentActivity {
    ViewPager Tab;
    TabPagerAdapter TabAdapter;
    ActionBar actionBar;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tab_layout);
        TabAdapter = new TabPagerAdapter(getSupportFragmentManager());
        Tab = (ViewPager)findViewById(R.id.pager);
        Tab.setOnPageChangeListener(
                new ViewPager.SimpleOnPageChangeListener() {
                    @Override
                    public void onPageSelected(int position) {
                        actionBar = getActionBar();
                        actionBar.setSelectedNavigationItem(position);                    }
                });
        Tab.setAdapter(TabAdapter);
        actionBar = getActionBar();

        //Enable Tabs on Action Bar
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        ActionBar.TabListener tabListener = new ActionBar.TabListener(){
            @Override
            public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
//              Toast.makeText(getBaseContext(), "Tab ReSelected: " + tab.getPosition(), Toast.LENGTH_SHORT).show();
            }
            @Override
            public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
                Tab.setCurrentItem(tab.getPosition());
//              Toast.makeText(getBaseContext(), "Tab Selected: " + tab.getPosition(), Toast.LENGTH_SHORT).show();
            }
            @Override
            public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
//              Toast.makeText(getBaseContext(), "Tab UnSelected: " + tab.getPosition(), Toast.LENGTH_SHORT).show();
            }};
            //Add New Tab
            actionBar.addTab(actionBar.newTab().setText("Tab1").setTabListener(tabListener));
            actionBar.addTab(actionBar.newTab().setText("Tab2").setTabListener(tabListener));

    }
}

这是TabPagerAdapter.java

public class TabPagerAdapter extends FragmentStatePagerAdapter {
    public TabPagerAdapter(FragmentManager fm) {
        super(fm);
    }
    @Override
    public Fragment getItem(int i) {
        switch (i) {
        case 0:
            return new Tab1Activity();
        case 1:
            return new Tab2Activity();
        }
        return null;
    }
    @Override
    public int getCount() {
        //No of Tabs
        return 2; 
    }
}

这是Tab1Activity.java

public class Tab1Activity extends Fragment {
    ViewPager tabPager;
    @Override
    public View onCreateView(final LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.activity_main2, container, false);
        tabPager = (ViewPager) container.findViewById(R.id.pager);
        List<String> dataList = prepareData();
        ListView listView = (ListView) view.findViewById(R.id.list_View1);
        ListRowAdaptor listAdapter = new ListRowAdaptor(inflater.getContext(), R.layout.list_row, dataList);
        listView.setAdapter(listAdapter);
        listView.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int pos, long id) {
                Bundle bundle = new Bundle();
                bundle.putStringArrayList("newData", (ArrayList<java.lang.String>) prepareNewData());

                Tab2Activity myDetailFragment = new Tab2Activity();
                myDetailFragment.setArguments(bundle);
                FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
                fragmentTransaction.add(R.id.pager, myDetailFragment);
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
                tabPager.setCurrentItem(1);
            }});
        return view;
    }

    public List<String> prepareData(){
        List<String> list = new ArrayList<String>();
        list.add("Item1");
        list.add("Item2");
        list.add("Item3");
        list.add("Item4");
        list.add("Item5");
        list.add("Item6");

        return list;
    }

    public List<String> prepareNewData(){
        List<String> list = new ArrayList<String>();
        list.add("New Item1");
        list.add("New Item2");
        list.add("New Item3");
        list.add("New Item4");
        list.add("New Item5");
        list.add("New Item6");

        return list;
    }
}

这是Tab2Activity.java

public class Tab2Activity extends Fragment {
    ListRowAdaptor listAdapter;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.activity_main2, container, false);
        Bundle bundle = getArguments();
        ListView listView = (ListView) view.findViewById(R.id.list_View1);
        List<String> dataList = prepareData();
        listAdapter = new ListRowAdaptor(inflater.getContext(), R.layout.list_row, dataList);

        if(bundle != null){
            List<String> newList = bundle.getStringArrayList("newData");

            listAdapter.clear();
            listAdapter.addAll(newList);
            listAdapter.notifyDataSetChanged();
        }
        listView.setAdapter(listAdapter);
        return view;
    }

    public List<String> prepareData(){
        List<String> list = new ArrayList<String>();
        list.add("Item11");
        list.add("Item22");
        list.add("Item33");
        list.add("Item44");
        list.add("Item55");
        list.add("Item66");

        return list;
    }
}

这是activity_main2.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/content_frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <ListView
        android:id="@+id/list_View1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >
    </ListView>
</LinearLayout>

这是tab_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/content_frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

这是list_row.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:padding="5dip" >
    <TextView
        android:id="@+id/txtName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"`enter code here`
        android:textColor="#343434"
        android:textSize="15sp" />
</RelativeLayout>*

Answer 1

可能错误是您设置了适配器

listView.setAdapter(listAdapter);

通知数据集已更改

listAdapter.notifyDataSetChanged();

您可以尝试在“通知”句子之前写下这些句子。

@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.activity_main2, container, false);
        Bundle bundle = getArguments();
        ListView listView = (ListView) view.findViewById(R.id.list_View1);
        List<String> dataList = prepareData();
        listAdapter = new ListRowAdaptor(inflater.getContext(), R.layout.list_row, dataList);

        if(bundle != null){
            List<String> newList = bundle.getStringArrayList("newData");

            listAdapter.clear();
            listAdapter.addAll(newList);
            listView.setAdapter(listAdapter);   // Update the adapter before notify
            listAdapter.notifyDataSetChanged();
        }
        return view;
    }

让我知道它是否有效。祝你好运。

Answer 2

将您的代码更改为

 if(bundle != null)
 {
      List<String> newList = bundle.getStringArrayList("newData");
      dataList.clear();
      dataList.addAll(newList);
      listAdapter.notifyDataSetChanged();
 }

Answer 3

notifyDataSetChanged()方法通知观察者您的适配器。

例如，如果您正在使用gridview，则可以调用invalidateViews()方法，这将导致视图重建并重新绘制。

即使在使用ArrayAdapter中的新数据更新后，更新ListView也会显示旧数据

3 个答案: