onCreateLoader不叫时，方向更改 [英] onCreateLoader not called when orientation changes
本文介绍了onCreateLoader不叫时，方向更改的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我的问题是基本相同的这一个：<一href="http://stackoverflow.com/questions/7810019/sometimes-dont-get-oncreateloader-callback-after-calling-initloader">Sometimes不要onCreateLoader调用回调后initLoader
我有2 ListFragments 包含在一个 ViewPager 。他们首先被装入好的，但是当我改变方向， initLoader 方法不叫 onCreateLoader 。
不过，如果我恢复到初始取向，一切又是罚款。
下面是我的code为 FragmentActivity ：
进口java.util.Locale中;
进口com.d.camera.R;
进口com.d.camera.R.id;
进口com.d.camera.R.layout;
进口com.d.camera.R.menu;
进口com.d.camera.R.string;
进口android.app.ActionBar;
进口android.app.FragmentTransaction;
进口android.os.Bundle;
进口android.support.v4.app.Fragment;
进口android.support.v4.app.FragmentActivity;
进口android.support.v4.app.FragmentManager;
进口android.support.v4.app.FragmentPagerAdapter;
进口android.support.v4.app.NavUtils;
进口android.support.v4.view.ViewPager;
进口android.view.Gravity;
进口android.view.LayoutInflater;
进口android.view.Menu;
进口android.view.MenuItem;
进口android.view.View;
进口android.view.ViewGroup;
进口android.widget.TextView;
公共类HistoryFragments扩展FragmentActivity工具
ActionBar.TabListener {
/ **
*在{@link android.support.v4.view.PagerAdapter}，将提供
*对于每个部分的片段。我们使用
* {@link android.support.v4.app.FragmentPagerAdapter}衍生物，它
*将让每一个加载的片段记忆。如果这成为过记忆
*密集，它可能是最好切换到
* {@link android.support.v4.app.FragmentStatePagerAdapter}。
* /
SectionsPagerAdapter mSectionsPagerAdapter;
/ **
*在{@link ViewPager}将承载部分内容。
* /
ViewPager mViewPager;
@覆盖
保护无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
的setContentView（R.layout.activity_history_fragments）;
//设置操作栏。
最后的动作条动作条= getActionBar（）;
actionBar.setNavigationMode（ActionBar.NAVIGATION_MODE_TABS）;
actionBar.setDisplayShowTitleEnabled（假）;
actionBar.setDisplayShowHomeEnabled（假）;
//创建将返回一个片段为三个的适配器
//应用程序的主要部分。
mSectionsPagerAdapter =新SectionsPagerAdapter（
getSupportFragmentManager（））;
//设置的ViewPager与部分适配器。
mViewPager =（ViewPager）findViewById（R.id.pager）;
mViewPager.setAdapter（mSectionsPagerAdapter）;
//当不同部分之间的刷卡，选择相应的
//标签。我们也可以使用ActionBar.Tab＃选择（）要做到这一点，如果我们有
//引用的标签。
mViewPager
.setOnPageChangeListener（新ViewPager.SimpleOnPageChangeListener（）{
@覆盖
公共无效onPageSelected（INT位置）{
actionBar.setSelectedNavigationItem（位置）;
}
}）;
//对于每个应用程序的章节中，添加一个标签，操作栏。
的for（int i = 0; I＆LT; mSectionsPagerAdapter.getCount（）;我++）{
//创建与对应于由所定义的页标题文本标签
//适配器。同时，指定此活动的对象，它实现
//该TabListener界面，回调（监听程序）进行时
//这个选项卡中选择。
actionBar.addTab（actionBar.newTab（）
.setText（mSectionsPagerAdapter.getPageTitle（I））
.setTabListener（本））;
}
}
@覆盖
公共布尔onCreateOptionsMenu（功能菜单）{
//充气菜单;这增加了项目操作栏，如果它是present。
。getMenuInflater（）膨胀（R.menu.history，菜单）;
返回true;
}
@覆盖
公共无效onTabSelected（ActionBar.Tab选项卡，
FragmentTransaction fragmentTransaction）{
//当选择给定的标签，切换到对应页面
//该ViewPager。
mViewPager.setCurrentItem（tab.getPosition（））;
}
@覆盖
公共无效onTabUnselected（ActionBar.Tab选项卡，
FragmentTransaction fragmentTransaction）{
}
@覆盖
公共无效onTabReselected（ActionBar.Tab选项卡，
FragmentTransaction fragmentTransaction）{
}
/ **
* A {@link FragmentPagerAdapter}返回对应的片段
*章节/标签/页之一。
* /
公共类SectionsPagerAdapter扩展FragmentPagerAdapter {
公共SectionsPagerAdapter（FragmentManager FM）{
超（FM）;
}
@覆盖
公共片段的getItem（INT位置）{
//的getItem被称为实例化片段给定的页面。
//返回一个DummySectionFragment（定义为静态内部类
下图）与页面数量作为其唯一的参数//。
片段片段= NULL;
如果（位置== 0）{
片段=新HistoryListFragment（）;
} 其他{
片段=新HistoryElemListFragment（）;
}
返回片段;
}
@覆盖
公众诠释getCount将（）{
//显示2总页数。
返回2;
}
@覆盖
公共CharSequence的getPageTitle（INT位置）{
区域设置L = Locale.getDefault（）;
开关（位置）{
情况下0：
返回的getString（R.string.title_section1）.toUpperCase（升）;
情况1：
返回的getString（R.string.title_section2）.toUpperCase（升）;
案例2：
返回的getString（R.string.title_section3）.toUpperCase（升）;
}
返回null;
}
}
}
和这里是之一code中的 ListFragments ：
进口的java.io.File;
进口java.text.SimpleDateFormat的;
进口java.util.Date;
进口java.util.Locale中;
进口com.d.camera.HistoryContentProvider;
进口com.d.camera.HistoryDatabase;
进口com.d.camera.HistoryEntry;
进口com.d.camera.R;
进口android.app.LoaderManager;
进口android.content.Context;
进口android.content.CursorLoader;
进口android.content.Intent;
进口android.content.Loader;
进口android.database.Cursor;
进口android.net.Uri;
进口android.os.Bundle;
进口android.support.v4.app.ListFragment;
进口android.util.Log;
进口android.view.ContextMenu;
进口android.view.LayoutInflater;
进口android.view.Menu;
进口android.view.MenuItem;
进口android.view.View;
进口android.view.ContextMenu.ContextMenuInfo;
进口android.view.ViewGroup;
进口android.widget.FilterQueryProvider;
进口android.widget.ListView;
进口android.widget.SimpleCursorAdapter;
进口android.widget.TextView;
进口android.widget.AdapterView.AdapterContextMenuInfo;
进口android.widget.SimpleCursorAdapter.ViewBinder;
公共类HistoryListFragment扩展ListFragment实现LoaderManager.LoaderCallbacks＆LT;光标＆GT; {
私有静态最终诠释LOADER_ID = 0×01;
私有静态最终诠释DELETE_ID = Menu.FIRST + 1;
公共静态最后弦乐SECTION_NUMBER =section_number标;
私人SimpleCursorAdapter适配器;
私人上下文的背景下;
公共HistoryListFragment（）{
}
@覆盖
公共无效onActivityCreated（包savedInstanceState）{
super.onActivityCreated（savedInstanceState）;
上下文= getActivity（）;
fillData（）;
registerForContextMenu（getListView（））;
}
@覆盖
公共查看onCreateView（LayoutInflater充气，容器的ViewGroup，
捆绑savedInstanceState）{
查看rootView = inflater.inflate（R.layout.list_fragment，集装箱，假）;
返回rootView;
}
私人无效fillData（）{
。getActivity（）getLoaderManager（）initLoader（LOADER_ID，空，这一点）。
的String []从=新的String [] {
HistoryDatabase.MOBILE_RESULT，
HistoryDatabase.FP_TIMESTAMP，
HistoryDatabase.PRODUCT_IMAGE，};
INT []到=新INT [] {
R.id.resultImage，
R.id.time，
R.id.productImage，};
适配器=新SimpleCursorAdapter（背景下，R.layout.history_element，空，从到，0）;
//我们要监视列表的设置和时间变化毫秒到可读的格式。*******
adapter.setViewBinder（新ViewBinder（）{
公共布尔setViewValue（视图V，光标C中，int参数：columnIndex）{
如果（参数：columnIndex == c.getColumnIndex（HistoryDatabase.FP_TIMESTAMP））
{
龙timeInMilli = c.getLong（c.getColumnIndex（HistoryDatabase.FP_TIMESTAMP））;
SimpleDateFormat的SDF =新的SimpleDateFormat（EEE MMM DD HH：MM：SSžYYYY，Locale.ENGLISH）;
字符串formatedTime = sdf.format（新日期（timeInMilli））;
TextView的电视=（TextView中）V;
tv.setText（formatedTime）;
返回true;
}
返回false;
}
}）;
// ********** *********************************************
setListAdapter（适配器）;
}
@覆盖
公共无效onCreateContextMenu（文本菜单菜单，视图V，
ContextMenuInfo menuInfo）{
super.onCreateContextMenu（菜单，V，menuInfo）;
menu.add（0，DELETE_ID，0，R.string.menu_delete）;
}
@覆盖
公共布尔onContextItemSelected（菜单项项）{
// ...
返回super.onContextItemSelected（项目）;
}
//反应到菜单选择
@覆盖
公共布尔onOptionsItemSelected（菜单项项）{
// ...
返回super.onOptionsItemSelected（项目）;
}
@覆盖
公共装载机＆LT;光标＆GT; onCreateLoader（INT ID，捆绑参数）{
的String []投影=新的String [] {HistoryDatabase.ID，HistoryDatabase.MOBILE_RESULT，HistoryDatabase.MOBILE_SCORE，HistoryDatabase.FP_TIMESTAMP，HistoryDatabase.PRODUCT_IMAGE，HistoryDatabase.QR_MESSAGE};
返回新CursorLoader（背景下，HistoryContentProvider.CONTENT_URI，投影，NULL，NULL，HistoryDatabase.ID +降序）;
}
@覆盖
公共无效onLoadFinished（装载机＆LT;光标＆GT; cursorLoader，光标光标）{
adapter.swapCursor（光标）;
}
@覆盖
公共无效onLoaderReset（装载机＆LT;光标＆GT; cursorLoader）{
adapter.swapCursor（空）;
}
公共无效onListItemClick（ListView的L，视图V，INT位置，长的id）{
//做一点事
}
}
我已经试过这些方法 destroyLoader ， restartLoader 不同的组合，但没有任何成功...是否任何人都知道这是怎么回事？
修改
使用 LoaderManager.enableDebugLogging（真）我得到以下日志：
第一负载给出了这样的
initLoader在LoaderManager {在HistoryFragments {424a7950 42507c68}}参数：args = NULL
首发：{的LoaderInfo＃424a7da0 1：CursorLoader {42faae18}}
创建新的装载机的LoaderInfo {424a7da0＃1：CursorLoader {42faae18}}
initLoader在LoaderManager {在HistoryFragments {424a7950 42507c68}}参数：args = NULL
首发：{的LoaderInfo＃42e5a280 2：CursorLoader {42e5a2f8}}
创建新的装载机的LoaderInfo {42e5a280＃2：CursorLoader {42e5a2f8}}
的onLoadComplete：{的LoaderInfo＃424a7da0 1：CursorLoader {42faae18}}
onLoadFinished在CursorLoader {42faae18 ID = 1}：CursorWrapperInner {42506d58}
的onLoadComplete：{的LoaderInfo＃42e5a280 2：CursorLoader {42e5a2f8}}
onLoadFinished在CursorLoader {42e5a2f8 ID = 2}：{CursorWrapperInner 42fab1f0}
然后当我改变方向，它给这个
护在LoaderManager {424a7950在HistoryFragments {42507c68}}
护：{的LoaderInfo＃42e5a280 2：CursorLoader {42e5a2f8}}
护：{的LoaderInfo＃424a7da0 1：CursorLoader {42faae18}}
销毁不活动的LoaderManager {在HistoryFragments 424a7950 {42507c68}}
initLoader在LoaderManager {在HistoryFragments {424a7950 426d0af0}}参数：args = NULL
重新使用现有的装载机的LoaderInfo {424a7da0＃1：CursorLoader {42faae18}}
initLoader在LoaderManager {在HistoryFragments {424a7950 426d0af0}}参数：args = NULL
重新使用现有的装载机的LoaderInfo {42e5a280＃2：CursorLoader {42e5a2f8}}
在LoaderManager成品护{424a7950在HistoryFragments {426d0af0}}
成品护：{的LoaderInfo＃42e5a280 2：CursorLoader {42e5a2f8}}
停止：{的LoaderInfo＃42e5a280 2：CursorLoader {42e5a2f8}}
成品护：{的LoaderInfo＃424a7da0 1：CursorLoader {42faae18}}
停止：{的LoaderInfo＃424a7da0 1：CursorLoader {42faae18}}
然后，当我再回到最初的方向，我得到一个错误，但随后一切都被再次加载：
保留在LoaderManager {在HistoryFragments {424a7950 426d0af0}}
调用doRetain时，不启动：LoaderManager {424a7950在HistoryFragments {426d0af0}}
java.lang.RuntimeException的：在这里
在android.app.LoaderManagerImpl.doRetain（LoaderManager.java:795）
在android.app.Activity.performStop（Activity.java:5497）
在android.app.ActivityThread.performDestroyActivity（ActivityThread.java:3591）
在android.app.ActivityThread.handleDestroyActivity（ActivityThread.java:3654）
在android.app.ActivityThread.handleRelaunchActivity（ActivityThread.java:3854）
在android.app.ActivityThread.access $ 800（ActivityThread.java:159）
在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1322）
在android.os.Handler.dispatchMessage（Handler.java:99）
在android.os.Looper.loop（Looper.java:176）
在android.app.ActivityThread.main（ActivityThread.java:5419）
在java.lang.reflect.Method.invokeNative（本机方法）
在java.lang.reflect.Method.invoke（Method.java:525）
在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1046）
在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:862）
在dalvik.system.NativeStart.main（本机方法）
销毁活动在LoaderManager {在HistoryFragments 424a7950 {426d0af0}}
销毁：{的LoaderInfo＃42e5a280 2：CursorLoader {42e5a2f8}}
CH375复位：{的LoaderInfo＃42e5a280 2：CursorLoader {42e5a2f8}}
销毁：{的LoaderInfo＃424a7da0 1：CursorLoader {42faae18}}
CH375复位：{的LoaderInfo＃424a7da0 1：CursorLoader {42faae18}}
销毁不活动的LoaderManager {在HistoryFragments 424a7950 {426d0af0}}
销毁活动在LoaderManager {在HistoryFragments 424a7950 {426d0af0}}
销毁不活动的LoaderManager {在HistoryFragments 424a7950 {426d0af0}}
initLoader在LoaderManager {在HistoryFragments {4271b070 42702c68}}参数：args = NULL
首发：{的LoaderInfo＃4271b690 1：CursorLoader {4271b708}}
创建新的装载机的LoaderInfo {4271b690＃1：CursorLoader {4271b708}}
initLoader在LoaderManager {在HistoryFragments {4271b070 42702c68}}参数：args = NULL
首发：{的LoaderInfo＃42720ab8 2：CursorLoader {42720b30}}
创建新的装载机的LoaderInfo {42720ab8＃2：CursorLoader {42720b30}}
的onLoadComplete：{的LoaderInfo＃4271b690 1：CursorLoader {4271b708}}
onLoadFinished在CursorLoader {4271b708 ID = 1}：CursorWrapperInner {4271f518}
的onLoadComplete：{的LoaderInfo＃42720ab8 2：CursorLoader {42720b30}}
onLoadFinished在CursorLoader {42720b30 ID = 2}：{CursorWrapperInner 427222c0}
日志然后重复自己进一步的方向改变。为什么在 CursorLoaders 被停止，并没有重新启动？我该如何重新启动呢？
编辑2
我固定我的问题感谢Nikis街，但他提出了一个有趣的问题：
为什么是 android.app.LoaderManager 不工作？
下面是使用支持版本后，日志。 第一负载给出了同样的事情上面，但方向改变后，再使用光标不会阻止他们。
护在LoaderManager {43945c70在HistoryFragments {427cb468}}
护：{的LoaderInfo＃439d8a58 2：CursorLoader {439d8ad0}}
护：{的LoaderInfo＃432dea88 1：CursorLoader {4393ad48}}
销毁不活动的LoaderManager {在HistoryFragments 43945c70 {427cb468}}
initLoader在LoaderManager {在HistoryFragments {43945c70 438f0a38}}参数：args = NULL
重新使用现有的装载机的LoaderInfo {432dea88＃1：CursorLoader {4393ad48}}
initLoader在LoaderManager {在HistoryFragments {43945c70 438f0a38}}参数：args = NULL
重新使用现有的装载机的LoaderInfo {439d8a58＃2：CursorLoader {439d8ad0}}
开始在LoaderManager {在HistoryFragments 43945c70 {438f0a38}}
在LoaderManager成品护{43945c70在HistoryFragments {438f0a38}}
成品护：{的LoaderInfo＃439d8a58 2：CursorLoader {439d8ad0}}
onLoadFinished在CursorLoader {439d8ad0 ID = 2}：{CursorWrapperInner 43952be0}
成品护：{的LoaderInfo＃432dea88 1：CursorLoader {4393ad48}}
onLoadFinished在CursorLoader {4393ad48 ID = 1}：CursorWrapperInner {43952fa8}
当我再回到最初的方向，这是结果：
护在LoaderManager {43945c70在HistoryFragments {438f0a38}}
护：{的LoaderInfo＃439d8a58 2：CursorLoader {439d8ad0}}
护：{的LoaderInfo＃432dea88 1：CursorLoader {4393ad48}}
销毁不活动的LoaderManager {在HistoryFragments 43945c70 {438f0a38}}
initLoader在LoaderManager {在HistoryFragments {43945c70 432cab50}}参数：args = NULL
重新使用现有的装载机的LoaderInfo {432dea88＃1：CursorLoader {4393ad48}}
initLoader在LoaderManager {在HistoryFragments {43945c70 432cab50}}参数：args = NULL
重新使用现有的装载机的LoaderInfo {439d8a58＃2：CursorLoader {439d8ad0}}
开始在LoaderManager {在HistoryFragments 43945c70 {432cab50}}
在LoaderManager成品护{43945c70在HistoryFragments {432cab50}}
成品护：{的LoaderInfo＃439d8a58 2：CursorLoader {439d8ad0}}
onLoadFinished在CursorLoader {439d8ad0 ID = 2}：{CursorWrapperInner 43952be0}
成品护：{的LoaderInfo＃432dea88 1：CursorLoader {4393ad48}}
onLoadFinished在CursorLoader {4393ad48 ID = 1}：CursorWrapperInner {43952fa8}
解决方案
您可以使用 LoaderManager.enableDebugLogging（真）来调试器行为，或者你可以尝试使用 getSupportLoadermanager（）而不是 getLoaderManager（）
My problem is basically the same as this one:Sometimes don't get onCreateLoader callback after calling initLoader
I have 2 ListFragments that are contained in a ViewPager. They get loaded ok at first, but when I change the orientation, the initLoadermethod doesn't call the onCreateLoader.
However, if I revert back to the initial orientation, all is fine again.
Here is my code for the FragmentActivity:
import java.util.Locale;
import com.d.camera.R;
import com.d.camera.R.id;
import com.d.camera.R.layout;
import com.d.camera.R.menu;
import com.d.camera.R.string;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.NavUtils;
import android.support.v4.view.ViewPager;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class HistoryFragments extends FragmentActivity implements
ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
* will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_history_fragments);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.setDisplayShowTitleEnabled(false);
actionBar.setDisplayShowHomeEnabled(false);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager
.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.history, menu);
return true;
}
@Override
public void onTabSelected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment = null;
if (position == 0) {
fragment = new HistoryListFragment();
} else{
fragment = new HistoryElemListFragment();
}
return fragment;
}
@Override
public int getCount() {
// Show 2 total pages.
return 2;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
}
and here is the code of one of the ListFragments:
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import com.d.camera.HistoryContentProvider;
import com.d.camera.HistoryDatabase;
import com.d.camera.HistoryEntry;
import com.d.camera.R;
import android.app.LoaderManager;
import android.content.Context;
import android.content.CursorLoader;
import android.content.Intent;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.util.Log;
import android.view.ContextMenu;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.ViewGroup;
import android.widget.FilterQueryProvider;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.SimpleCursorAdapter.ViewBinder;
public class HistoryListFragment extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor>{
private static final int LOADER_ID = 0x01;
private static final int DELETE_ID = Menu.FIRST + 1;
public static final String SECTION_NUMBER = "section_number";
private SimpleCursorAdapter adapter;
private Context context;
public HistoryListFragment() {
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
context = getActivity();
fillData();
registerForContextMenu(getListView());
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.list_fragment, container, false);
return rootView;
}
private void fillData() {
getActivity().getLoaderManager().initLoader(LOADER_ID, null, this);
String[] from = new String[] {
HistoryDatabase.MOBILE_RESULT,
HistoryDatabase.FP_TIMESTAMP,
HistoryDatabase.PRODUCT_IMAGE,};
int[] to = new int[] {
R.id.resultImage,
R.id.time,
R.id.productImage,};
adapter = new SimpleCursorAdapter(context, R.layout.history_element, null, from, to, 0);
// We want monitor the list setup and change the milliseconds time to a readable format.*******
adapter.setViewBinder(new ViewBinder(){
public boolean setViewValue(View v, Cursor c, int columnIndex) {
if(columnIndex == c.getColumnIndex(HistoryDatabase.FP_TIMESTAMP))
{
Long timeInMilli = c.getLong(c.getColumnIndex(HistoryDatabase.FP_TIMESTAMP));
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy", Locale.ENGLISH);
String formatedTime = sdf.format(new Date(timeInMilli));
TextView tv = (TextView)v;
tv.setText(formatedTime);
return true;
}
return false;
}
});
//*********************************************************************************************
setListAdapter(adapter);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
menu.add(0, DELETE_ID, 0, R.string.menu_delete);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
//...
return super.onContextItemSelected(item);
}
// Reaction to the menu selection
@Override
public boolean onOptionsItemSelected(MenuItem item) {
//...
return super.onOptionsItemSelected(item);
}
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
String[] projection = new String[]{HistoryDatabase.ID, HistoryDatabase.MOBILE_RESULT, HistoryDatabase.MOBILE_SCORE, HistoryDatabase.FP_TIMESTAMP, HistoryDatabase.PRODUCT_IMAGE, HistoryDatabase.QR_MESSAGE};
return new CursorLoader(context, HistoryContentProvider.CONTENT_URI, projection, null, null, HistoryDatabase.ID + " DESC");
}
@Override
public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {
adapter.swapCursor(cursor);
}
@Override
public void onLoaderReset(Loader<Cursor> cursorLoader) {
adapter.swapCursor(null);
}
public void onListItemClick(ListView l, View v, int position, long id) {
//do something
}
}
I've tried different combinations of these methods destroyLoader,restartLoader, but without any success... Does anyone know what's going on?
Edit
Using LoaderManager.enableDebugLogging(true) I get the following logs:
The first load gives this
initLoader in LoaderManager{424a7950 in HistoryFragments{42507c68}}: args=null
Starting: LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
Created new loader LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
initLoader in LoaderManager{424a7950 in HistoryFragments{42507c68}}: args=null
Starting: LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
Created new loader LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
onLoadComplete: LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
onLoadFinished in CursorLoader{42faae18 id=1}: CursorWrapperInner{42506d58}
onLoadComplete: LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
onLoadFinished in CursorLoader{42e5a2f8 id=2}: CursorWrapperInner{42fab1f0}
Then when I change the orientation, it gives this
Retaining in LoaderManager{424a7950 in HistoryFragments{42507c68}}
Retaining: LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
Retaining: LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
Destroying Inactive in LoaderManager{424a7950 in HistoryFragments{42507c68}}
initLoader in LoaderManager{424a7950 in HistoryFragments{426d0af0}}: args=null
Re-using existing loader LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
initLoader in LoaderManager{424a7950 in HistoryFragments{426d0af0}}: args=null
Re-using existing loader LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
Finished Retaining in LoaderManager{424a7950 in HistoryFragments{426d0af0}}
Finished Retaining: LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
Stopping: LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
Finished Retaining: LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
Stopping: LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
Then when I come back to the initial orientation, I get an error but then everything gets loaded again:
Retaining in LoaderManager{424a7950 in HistoryFragments{426d0af0}}
Called doRetain when not started: LoaderManager{424a7950 in HistoryFragments{426d0af0}}
java.lang.RuntimeException: here
at android.app.LoaderManagerImpl.doRetain(LoaderManager.java:795)
at android.app.Activity.performStop(Activity.java:5497)
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3591)
at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3654)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3854)
at android.app.ActivityThread.access$800(ActivityThread.java:159)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1322)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
at dalvik.system.NativeStart.main(Native Method)
Destroying Active in LoaderManager{424a7950 in HistoryFragments{426d0af0}}
Destroying: LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
Reseting: LoaderInfo{42e5a280 #2 : CursorLoader{42e5a2f8}}
Destroying: LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
Reseting: LoaderInfo{424a7da0 #1 : CursorLoader{42faae18}}
Destroying Inactive in LoaderManager{424a7950 in HistoryFragments{426d0af0}}
Destroying Active in LoaderManager{424a7950 in HistoryFragments{426d0af0}}
Destroying Inactive in LoaderManager{424a7950 in HistoryFragments{426d0af0}}
initLoader in LoaderManager{4271b070 in HistoryFragments{42702c68}}: args=null
Starting: LoaderInfo{4271b690 #1 : CursorLoader{4271b708}}
Created new loader LoaderInfo{4271b690 #1 : CursorLoader{4271b708}}
initLoader in LoaderManager{4271b070 in HistoryFragments{42702c68}}: args=null
Starting: LoaderInfo{42720ab8 #2 : CursorLoader{42720b30}}
Created new loader LoaderInfo{42720ab8 #2 : CursorLoader{42720b30}}
onLoadComplete: LoaderInfo{4271b690 #1 : CursorLoader{4271b708}}
onLoadFinished in CursorLoader{4271b708 id=1}: CursorWrapperInner{4271f518}
onLoadComplete: LoaderInfo{42720ab8 #2 : CursorLoader{42720b30}}
onLoadFinished in CursorLoader{42720b30 id=2}: CursorWrapperInner{427222c0}
The logs then repeat themselves for further orientation changes. Why are the CursorLoaders being stopped and not restarted? How can I restart them?
EDIT 2
I fixed my problem thanks to nikis, but he raised an interesting question:
why was the android.app.LoaderManager not working?
Here's the logs after using the support version. The first load gives the same thing as above, but after the orientation change, re-using the cursors doesn't stop them.
Retaining in LoaderManager{43945c70 in HistoryFragments{427cb468}}
Retaining: LoaderInfo{439d8a58 #2 : CursorLoader{439d8ad0}}
Retaining: LoaderInfo{432dea88 #1 : CursorLoader{4393ad48}}
Destroying Inactive in LoaderManager{43945c70 in HistoryFragments{427cb468}}
initLoader in LoaderManager{43945c70 in HistoryFragments{438f0a38}}: args=null
Re-using existing loader LoaderInfo{432dea88 #1 : CursorLoader{4393ad48}}
initLoader in LoaderManager{43945c70 in HistoryFragments{438f0a38}}: args=null
Re-using existing loader LoaderInfo{439d8a58 #2 : CursorLoader{439d8ad0}}
Starting in LoaderManager{43945c70 in HistoryFragments{438f0a38}}
Finished Retaining in LoaderManager{43945c70 in HistoryFragments{438f0a38}}
Finished Retaining: LoaderInfo{439d8a58 #2 : CursorLoader{439d8ad0}}
onLoadFinished in CursorLoader{439d8ad0 id=2}: CursorWrapperInner{43952be0}
Finished Retaining: LoaderInfo{432dea88 #1 : CursorLoader{4393ad48}}
onLoadFinished in CursorLoader{4393ad48 id=1}: CursorWrapperInner{43952fa8}
And when I come back to the initial orientation, this is the result:
Retaining in LoaderManager{43945c70 in HistoryFragments{438f0a38}}
Retaining: LoaderInfo{439d8a58 #2 : CursorLoader{439d8ad0}}
Retaining: LoaderInfo{432dea88 #1 : CursorLoader{4393ad48}}
Destroying Inactive in LoaderManager{43945c70 in HistoryFragments{438f0a38}}
initLoader in LoaderManager{43945c70 in HistoryFragments{432cab50}}: args=null
Re-using existing loader LoaderInfo{432dea88 #1 : CursorLoader{4393ad48}}
initLoader in LoaderManager{43945c70 in HistoryFragments{432cab50}}: args=null
Re-using existing loader LoaderInfo{439d8a58 #2 : CursorLoader{439d8ad0}}
Starting in LoaderManager{43945c70 in HistoryFragments{432cab50}}
Finished Retaining in LoaderManager{43945c70 in HistoryFragments{432cab50}}
Finished Retaining: LoaderInfo{439d8a58 #2 : CursorLoader{439d8ad0}}
onLoadFinished in CursorLoader{439d8ad0 id=2}: CursorWrapperInner{43952be0}
Finished Retaining: LoaderInfo{432dea88 #1 : CursorLoader{4393ad48}}
onLoadFinished in CursorLoader{4393ad48 id=1}: CursorWrapperInner{43952fa8}
解决方案
You can use LoaderManager.enableDebugLogging(true) to debug your loader behavior or you can try to use getSupportLoadermanager() instead of getLoaderManager()
这篇关于onCreateLoader不叫时，方向更改的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
