在我的应用程序中，4 个片段附加到一个活动类。在我的活动类中，我使用它设置了根内容视图
setContentView(R.layout.fragment_pager);
我的四个片段位于单独的 java 文件中。
在我的一个片段中，我正在显示我使用的联系人列表
mAdapter = new SimpleCursorAdapter(getActivity(),
android.R.layout.simple_list_item_1, null,
new String[] {ContactsContract.Contacts.DISPLAY_NAME},
new int[] { android.R.id.text1}, 0);
setListAdapter(mAdapter);
setListShown(true);
我想知道在我的情况下 setListAdapter 的用途是什么以及它将 SimpleCursorAdapter 类给出的内容列表放在哪里？以及如何设置片段的标题。
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:drawable/gallery_thumb">
<TextView android:id="@+id/text"
android:layout_width="match_parent" android:layout_height="wrap_content"
android:gravity="center_vertical|center_horizontal"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="@string/hello_world"/>
<!-- The frame layout is here since we will be showing either
the empty view or the list view. -->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dip"
android:layout_weight="1" >
<!-- Here is the list. Since we are using a ListActivity, we
have to call it "@android:id/list" so ListActivity will
find it -->
<ListView android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:drawSelectorOnTop="false"/>
<!-- Here is the view to show if the list is emtpy -->
<TextView android:id="@android:id/empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="No items."/>
</FrameLayout>
</LinearLayout>
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
mAdapter = new SimpleCursorAdapter(getActivity(),
android.R.layout.simple_list_item_1, null,
new String[] {ContactsContract.Contacts.DISPLAY_NAME},
new int[] { android.R.id.text1}, 0);
//setListAdapter(mAdapter);
// setListShown(true);
// getLoaderManager().initLoader(0, null, this);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_pager_list, container, false);
View tv = v.findViewById(R.id.text);
((TextView)tv).setText("Contacts");
return v;
}
当我使用此方法并删除两个方法 onCreate 和 onCreateView 时，我的光标显示数据
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mAdapter = new SimpleCursorAdapter(getActivity(),
android.R.layout.simple_list_item_1, null,
new String[] {ContactsContract.Contacts.DISPLAY_NAME},
new int[] { android.R.id.text1}, 0);
setListAdapter(mAdapter);
setListShown(true);
getLoaderManager().initLoader(0, null, this);
}
但是当我同时使用这三种方法时，我的应用程序会意外停止。当我同时使用这三种方法时会出现什么错误？
package com.keepintouch.android;
import android.os.Bundle;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.provider.ContactsContract;
import android.support.v4.app.Fragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.SimpleCursorAdapter;
import android.util.Log;
import android.view.View;
import android.widget.ListView;
import com.actionbarsherlock.app.SherlockListFragment;
public class ContactsFragment extends SherlockListFragment implements LoaderManager.LoaderCallbacks<Cursor>{
// This is the Adapter being used to display the list's data.
SimpleCursorAdapter mAdapter;
// If non-null, this is the current filter the user has provided.
String mCurFilter;
View lv;
// These are the Contacts rows that we will retrieve.
static final String[] CONTACTS_SUMMARY_PROJECTION = new String[] {
ContactsContract.Contacts._ID,
ContactsContract.Contacts.DISPLAY_NAME,
};
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
}
public static Fragment newInstance(Context context){
ContactsFragment contactFragment = new ContactsFragment();
return contactFragment;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mAdapter = new SimpleCursorAdapter(getActivity(),
android.R.layout.simple_list_item_1, null,
new String[] {ContactsContract.Contacts.DISPLAY_NAME},
new int[] { android.R.id.text1}, 0);
setListAdapter(mAdapter);
setListShown(true);
getLoaderManager().initLoader(0, null, this);
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Insert desired behavior here.
Log.i("FragmentComplexList", "Item clicked: " + id);
}
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
// This is called when a new Loader needs to be created. This
// sample only has one Loader, so we don't care about the ID.
// First, pick the base URI to use depending on whether we are
// currently filtering.
Uri baseUri;
if (mCurFilter != null) {
baseUri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_FILTER_URI,
Uri.encode(mCurFilter));
} else {
baseUri = ContactsContract.Contacts.CONTENT_URI;
}
// Now create and return a CursorLoader that will take care of
// creating a Cursor for the data being displayed.
String select = "((" + ContactsContract.Contacts.DISPLAY_NAME + " NOTNULL) AND ("
+ ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1) AND ("
+ ContactsContract.Contacts.DISPLAY_NAME + " != '' ))";
return new CursorLoader(getActivity(), baseUri,
CONTACTS_SUMMARY_PROJECTION, select, null,
ContactsContract.Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC");
}
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
// Swap the new cursor in. (The framework will take care of closing the
// old cursor once we return.)
mAdapter.swapCursor(data);
// The list should now be shown.
if (isResumed()) {
setListShown(true);
} else {
setListShownNoAnimation(true);
}
}
public void onLoaderReset(Loader<Cursor> loader) {
// This is called when the last Cursor provided to onLoadFinished()
// above is about to be closed. We need to make sure we are no
// longer using it.
mAdapter.swapCursor(null);
}
}