【发布时间】：2014-04-01 22:04:59
【问题描述】：
我将 Eclipse 模板用于我的主要活动，该活动使用带有滑动视图的选项卡。总共有 5 个选项卡，每个选项卡将承载应用程序的一部分。我从一个标有“人员”的选项卡开始我的实施。当用户第一次选择 Personnel 选项卡时，他们将获得一个 ListView 人员列表。当用户从列表中选择一个人时，我想在旧片段之上创建一个新片段（就像开始一个新活动一样），但在同一个选项卡中。当用户导航到新选项卡然后返回时，详细视图应该仍然存在。关闭详细视图时，应重新显示人员列表。
如何在单个选项卡中创建新片段并保留整个选项卡的状态？
MainActivity.java
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.view.ViewPager;
import android.view.Menu;
import android.view.MenuItem;
import java.util.Locale;
public class MainActivity extends FragmentActivity implements ActionBar.TabListener,
UnitsFragment.OnUnitSelectedListener {
/**
* 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 int getCount() {
// Show 5 total pages.
return 5;
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
switch (position) {
case 0:
return new AccountabilityFragment();
case 1:
return new EventsFragment();
case 2:
return new MeFragment();
case 3:
return new PersonnelFragment();
case 4:
return new UnitsFragment();
}
return null;
}
@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);
case 3:
return getString(R.string.title_section4).toUpperCase(l);
case 4:
return getString(R.string.title_section5).toUpperCase(l);
}
return null;
}
}
/**
* 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;
static boolean mShowMenuAdd = true;
static boolean mShowMenuSearch = true;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_add:
return true;
case R.id.action_search:
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
menu.findItem(R.id.action_add).setVisible(mShowMenuAdd);
menu.findItem(R.id.action_search).setVisible(mShowMenuSearch);
return true;
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mShowMenuAdd = setMenuAddVisible(tab.getPosition());
mShowMenuSearch = setMenuSearchVisible(tab.getPosition());
invalidateOptionsMenu();
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 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 five
// 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++) {
actionBar.addTab(
actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
private boolean setMenuAddVisible(int tab) {
switch (tab) {
case 0:
return false;
case 1:
return false;
case 2:
return false;
case 3:
return false;
case 4:
return true;
}
return false;
}
private boolean setMenuSearchVisible(int tab) {
switch (tab) {
case 0:
return false;
case 1:
return false;
case 2:
return false;
case 3:
return false;
case 4:
return true;
}
return false;
}
}
PersonnelFragment.java
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class PersonnelFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_personnel, container, false);
TextView dummyTextView = (TextView) rootView.findViewById(R.id.textUnitsHeader);
dummyTextView.setText("Personnel Layout Placeholder");
return rootView;
}
}
【问题讨论】：
标签： android android-fragments tabs