Question

我有一个DB，我正在尝试连接到listView（通过CursorAdapter）

我关注：Populating a ListView with a CursorAdapter 但是我错过了什么，因为我在列表视图中看不到任何东西。

我有一个包含片段的活动：

<fragment
        android:id="@+id/fragmnet_main_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="keepInTouch.today.MainListFragment"
        tools:layout="@layout/fragment_main_list" />

片段看起来：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="keepInTouch.today.MainListFragment">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/mainFragmentListTitle"
        android:background="#e43d3d"
        android:textColor="#371b1b" />


    <ListView
        android:id="@+id/lvKits"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

每个列表项看起来都是：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""/>

</LinearLayout>

cursorAdpter看起来：

public class ContactsCursorAdapter  extends CursorAdapter{

    public ContactsCursorAdapter(Context context, Cursor cursor)
    {
        super(context, cursor, 0);
    }

    @Override
    public View  newView(Context context, Cursor cursor, ViewGroup parent) {
        return LayoutInflater.from(context).inflate(R.layout.today_view, parent, false);
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {
        TextView tvTitle = (TextView) view.findViewById(R.id.tvTitle);
        String title = cursor.getString(cursor.getColumnIndexOrThrow(KitSqliteOpenHelper.KEY_KIT_TITLE));
        tvTitle.setText(title);
    }
}

在激活onCreate（和更新后）我正在调用此函数：

   private void updateListView() {

        MainListFragment mainListFragment = (MainListFragment)getSupportFragmentManager().findFragmentById(R.id.fragmnet_main_list);
        Cursor cursor = KitSqliteOpenHelper.getInstance(this).getAllRawKits();
        TextView textView = (TextView) findViewById(R.id.textV);
        textView.setText("Total: " + cursor.getCount());
        mainListFragment.updateListView();
    }



 public Cursor getAllRawKits()
    {
        SQLiteDatabase db = getWritableDatabase();
        String QUERY_SELECT_ALL = String.format("SELECT * FROM %s", TABLE_KIT);
        Cursor cursor = db.rawQuery(QUERY_SELECT_ALL, null);
        return cursor;
    }


public class MainListFragment extends Fragment {

    ContactsCursorAdapter contactsCursorAdapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,  Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_main_list, container, false);
        createContactsCursorAdapter(view);
        return inflater.inflate(R.layout.fragment_main_list, container, false);
    }


    private void createContactsCursorAdapter(View view)
    {
        Cursor cursor = KitSqliteOpenHelper.getInstance(getActivity()).getAllRawKits();
        contactsCursorAdapter = new ContactsCursorAdapter(getActivity(), cursor);
        ListView lvItems = (ListView) view.findViewById(R.id.lvKits);
        lvItems.setAdapter(contactsCursorAdapter);
    }

    public void updateListView() {
        Cursor cursor = KitSqliteOpenHelper.getInstance(getActivity()).getAllRawKits();
        contactsCursorAdapter.changeCursor(cursor);
        contactsCursorAdapter.notifyDataSetChanged();
        //contactsCursorAdapter.swapCursor(cursor);
    }
}

我看到我有6个项目（光标大小），但在listView

中没有查看任何元素

我曾尝试更换（仅用于调试）：

  tvTitle.setText(title);

tvTitle.setText("test");

在ContactsCursorAdapter中，bindView 我得到了同样的结果......

经过更多调试后，似乎没有调用来自ContactsCursorAdapter的newView和bindView。为什么？

主要活动看起来：

public class MainActivity extends AppCompatActivity {
//public class MainActivity extends FragmentActivity {


    public MemoResultReciver memoResultReciver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        KitSqliteOpenHelper.getInstance(this);
        updateListView();
    }




    static final int PICK_CONTACT_DETAILS = 1;
    public void onClickButton(View v) {
        Intent intent = new Intent(this, ChooseContactActivity.class);
        startActivityForResult(intent, PICK_CONTACT_DETAILS);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // Check which request we're responding to
        if (requestCode == PICK_CONTACT_DETAILS) {
            // Make sure the request was successful
            if (resultCode == RESULT_OK) {
                TextView textView = (TextView) findViewById(R.id.textV);

                KitContactInfo kitContactInfo = data.getParcelableExtra("KitInfo");
                String kitName = kitContactInfo.title;
                Toast.makeText(getApplicationContext(), kitName + " was added", Toast.LENGTH_SHORT).show();
                updateListView();
            }
        }
    }

    private void updateListView() {

        MainListFragment mainListFragment = (MainListFragment)getSupportFragmentManager().findFragmentById(R.id.fragmnet_main_list);
        Cursor cursor = KitSqliteOpenHelper.getInstance(this).getAllRawKits();
        TextView textView = (TextView) findViewById(R.id.textV);
        textView.setText("Total: " + cursor.getCount());
        mainListFragment.updateListView();
    }

    public void scheduleAlarm(KitContactInfo kitContactInfo)
    {
        // Construct an intent that will execute the AlarmReceiver
        Intent intent = new Intent(getApplicationContext(), SchdulerBroadcastReceiver.class);
        udateMemoService(intent, kitContactInfo.contactPhone, kitContactInfo.contactName);

        // Create a PendingIntent to be triggered when the alarm goes off
        final PendingIntent pIntent = PendingIntent.getBroadcast(this, SchdulerBroadcastReceiver.REQUEST_CODE,  intent, PendingIntent.FLAG_UPDATE_CURRENT);
        AlarmManager alarm = (AlarmManager) this.getSystemService(Context.ALARM_SERVICE);
        Calendar calander = Calendar.getInstance();
        calander.set(kitContactInfo.year ,kitContactInfo.month, kitContactInfo.day, kitContactInfo.hour, kitContactInfo.min, 0);
        alarm.set(AlarmManager.RTC, calander.getTimeInMillis(), pIntent);
    }


    private void udateMemoService(Intent intent,String number, String msg) {
        intent.putExtra("PhoneNumber", number);
        intent.putExtra("Message", msg);
    }
}

Answer 1

好吧，我看不到足够的信息，因为我看不到整个代码的实现，但有一些东西可以计数，也许是问题，当你在活动中onCreate（）时片段没有连接到活动，所以当您从updateListView() onCreate()调用片段中的getActivity()时，ListView应返回空值。

正如我告诉你的那样，我不确定，如果你添加了整个Activity实现，你确定你正在创建并正确地将片段附加到活动，因为问题可能与活动有关显示片段而不是# weekend cache <FilesMatch ".(jpg|jpeg|png|gif|swf)$"> <IfModule mod_headers.c> Header set Cache-Control "max-age=604800, public" </IfModule> </FilesMatch> <FilesMatch ".(xml|txt|css|js)$"> <IfModule mod_headers.c> Header set Cache-Control "max-age=604800, proxy-revalidate" </IfModule> </FilesMatch>本身。

Answer 2

尝试通过以下方式替换MainActivity updateListView：

private void updateListView() {

        FragmentManager fm = getFragmentManager();

        FragmentTransaction f = fm.beginTransaction();
        f.add(R.id.R.id.fragmnet_main_list, new MainListFragment());
        f.commit();


        MainListFragment mainListFragment = (MainListFragment)getSupportFragmentManager().findFragmentById(R.id.fragmnet_main_list);
        Cursor cursor = KitSqliteOpenHelper.getInstance(this).getAllRawKits();
        TextView textView = (TextView) findViewById(R.id.textV);
        textView.setText("Total: " + cursor.getCount());
        mainListFragment.updateListView();
    }
}

为什么我在listview上看不到任何东西？

2 个答案: