我试图在android studio生成的模板中获取一个列表片段，用于制表符并在它们之间滑动。
症状是片段在活动开始时执行一次，但如果更改了选项卡则不再执行。 它从不显示内容（无论是活动开始还是其他方式）。
样板代码如下：
package com.responseapp.android.activity;
import java.util.Locale;
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.support.v13.app.FragmentPagerAdapter;
import android.os.Bundle;
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;
import com.responseapp.android.R;
public class TestActivity extends Activity implements ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link 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.v13.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_test2);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());
// 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.test, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@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 PlaceholderFragment (defined as a static inner class below).
return PlaceholderFragment.newInstance(position + 1);
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@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;
}
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_test2, container, false);
return rootView;
}
}
}
我做了以下几乎没有成功：
package com.responseapp.android.ui;
import android.app.ActionBar;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v13.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import com.activeandroid.ActiveAndroid;
import com.responseapp.android.R;
import com.responseapp.android.model.Trip;
import com.responseapp.android.ui.authorisation.LoginActivity;
import com.responseapp.android.ui.trips.CreateTripActivity;
import java.util.Locale;
import uk.co.senab.actionbarpulltorefresh.library.ActionBarPullToRefresh;
import uk.co.senab.actionbarpulltorefresh.library.PullToRefreshLayout;
public class HomeActivity extends Activity implements ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link 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;
private static final String STATE_SELECTED_NAVIGATION_ITEM = "selected_navigation_item";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
ActiveAndroid.initialize(this);
SharedPreferences sharedPref = getSharedPreferences("com.responseapp.app.SHARED", 0);
boolean loggedIn = sharedPref.getBoolean("LOGGED_IN", false);
if (!loggedIn) {
Intent intent = new Intent(this, LoginActivity.class);
startActivity(intent);
finish();
}
// Set up the action bar.
final ActionBar actionBar = getActionBar();
if (actionBar != null) {
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
}
// Create the adapter that will return a fragment for each of the
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
getActionBar().setTitle("Response");
// 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) {
if (actionBar != null) {
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.
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.home, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_logout) {
SharedPreferences sharedPref = getSharedPreferences("com.responseapp.app.SHARED", 0);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putBoolean("LOGGED_IN", false);
editor.commit();
Intent intent = new Intent(this, LoginActivity.class);
startActivity(intent);
finish();
return true;
}
if (id == R.id.action_new_trip) {
Intent intent = new Intent(this, CreateTripActivity.class);
startActivity(intent);
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Called when a tab enters the selected state.
*
* @param tab The tab that was selected
* @param ft A {@link android.app.FragmentTransaction} for queuing fragment operations to execute
* during a tab switch. The previous tab's unselect and this tab's select will be
* executed in a single transaction. This FragmentTransaction does not support
*/
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
mViewPager.setCurrentItem(tab.getPosition());
System.out.println("FRAGMENT TAPPED!");
}
/**
* Called when a tab exits the selected state.
*
* @param tab The tab that was unselected
* @param ft A {@link android.app.FragmentTransaction} for queuing fragment operations to execute
* during a tab switch. This tab's unselect and the newly selected tab's select
* will be executed in a single transaction. This FragmentTransaction does not
*/
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
/**
* Called when a tab that is already selected is chosen again by the user.
* Some applications may use this action to return to the top level of a category.
*
* @param tab The tab that was reselected.
* @param ft A {@link android.app.FragmentTransaction} for queuing fragment operations to execute
* once this method returns. This FragmentTransaction does not support
*/
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
/**
* 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) {
String type = position == 0 ? "all" : "managed";
System.out.println("GOT THIS FAR");
return TripListFragment.newInstance(type);
}
@Override
public int getCount() {
return 2;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.all_trips_title).toUpperCase(l);
case 1:
return getString(R.string.managed_trips_title).toUpperCase(l);
}
return null;
}
}
/**
* A trip list fragment containing a simple view.
*/
public static class TripListFragment extends Fragment implements AdapterView.OnItemClickListener {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_TYPE = "all";
/**
* The fragment's ListView/GridView.
*/
private AbsListView mListView;
/**
* The Adapter which will be used to populate the ListView/GridView with
* Views.
*/
private ListAdapter mAdapter;
private PullToRefreshLayout mPullToRefreshLayout;
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static TripListFragment newInstance(String sectionType) {
TripListFragment fragment = new TripListFragment();
Bundle args = new Bundle();
args.putString(ARG_SECTION_TYPE, sectionType);
fragment.setArguments(args);
return fragment;
}
public TripListFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
System.out.println("BEING CALLED");
if(ARG_SECTION_TYPE == "all") {
mAdapter = new ArrayAdapter<Trip.TripItem>(getActivity(),
android.R.layout.two_line_list_item, android.R.id.text1, Trip.getAllAsItems(0));
} else {
mAdapter = new ArrayAdapter<Trip.TripItem>(getActivity(),
android.R.layout.two_line_list_item, android.R.id.text1, Trip.getManagedAsItems(0));
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_triplist, container, false);
mPullToRefreshLayout = new PullToRefreshLayout(container.getContext());
// Set the adapter
mListView = (AbsListView) view.findViewById(android.R.id.list);
mListView.setAdapter(mAdapter);
// Set OnItemClickListener so we can be notified on item clicks
mListView.setOnItemClickListener(this);
System.out.println("VIEW:"+view.toString());
return view;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Trip.TripItem trip = (Trip.TripItem) parent.getItemAtPosition(position);
HomeActivity.onFragmentInteraction(1, trip.id);
}
}
private static void onFragmentInteraction(int i, int id) {
}
}
不同之处在于嵌入在主类中的片段类。 在样板中：
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_test2, container, false);
return rootView;
}
}
在我的代码中：
/**
* A trip list fragment containing a simple view.
*/
public static class TripListFragment extends Fragment implements AdapterView.OnItemClickListener {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_TYPE = "all";
/**
* The fragment's ListView/GridView.
*/
private AbsListView mListView;
/**
* The Adapter which will be used to populate the ListView/GridView with
* Views.
*/
private ListAdapter mAdapter;
private PullToRefreshLayout mPullToRefreshLayout;
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static TripListFragment newInstance(String sectionType) {
TripListFragment fragment = new TripListFragment();
Bundle args = new Bundle();
args.putString(ARG_SECTION_TYPE, sectionType);
fragment.setArguments(args);
return fragment;
}
public TripListFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
System.out.println("BEING CALLED");
if(ARG_SECTION_TYPE == "all") {
mAdapter = new ArrayAdapter<Trip.TripItem>(getActivity(),
android.R.layout.two_line_list_item, android.R.id.text1, Trip.getAllAsItems(0));
} else {
mAdapter = new ArrayAdapter<Trip.TripItem>(getActivity(),
android.R.layout.two_line_list_item, android.R.id.text1, Trip.getManagedAsItems(0));
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_triplist, container, false);
mPullToRefreshLayout = new PullToRefreshLayout(container.getContext());
// Set the adapter
mListView = (AbsListView) view.findViewById(android.R.id.list);
mListView.setAdapter(mAdapter);
// Set OnItemClickListener so we can be notified on item clicks
mListView.setOnItemClickListener(this);
System.out.println("VIEW:"+view.toString());
return view;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Trip.TripItem trip = (Trip.TripItem) parent.getItemAtPosition(position);
HomeActivity.onFragmentInteraction(1, trip.id);
}
}
非常感谢任何帮助。