I have the following code :
MainActivity.java
package com.erc.library;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.FragmentTransaction;
import android.content.SharedPreferences;
import android.content.res.Resources;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Environment;
import android.os.StrictMode;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;
import com.erc.sayeghlibrary.adapter.TabsPagerAdapter;
public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {
private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
// Tab titles
private String[] tabs = { "Stories", "Dictionaries", "eBooks"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int actionBarTitleId = Resources.getSystem().getIdentifier("action_bar_title", "id", "android");
if (actionBarTitleId > 0) {
TextView title = (TextView) findViewById(actionBarTitleId);
if (title != null) {
title.setTextColor(Color.WHITE);
}
}
// Initilization
viewPager = (ViewPager) findViewById(R.id.pager);
actionBar = getActionBar();
mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Adding Tabs
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name)
.setTabListener(this));
}
/**
* on swiping the viewpager make respective tab selected
* */
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// on changing the page
// make respected tab selected
actionBar.setSelectedNavigationItem(position);
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
});
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// on tab selected
// show respected fragment view
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
// action with ID action_refresh was selected
case R.id.Favorites:
Toast.makeText(this, "Favorites selected", Toast.LENGTH_SHORT)
.show();
break;
// action with ID action_settings was selected
default:
break;
}
return true;
}
}
TabsPagerAdapter.java
package com.erc.library.adapter;
import com.erc.library.Dictionaries;
import com.erc.library.Ebooks;
import com.erc.library.Stories;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int index) {
switch (index) {
case 0:
return new Stories();
case 1:
return new Dictionaries();
case 2:
// Movies fragment activity
return new Ebooks();
}
return null;
}
@Override
public int getCount() {
// get item count - equal to number of tabs
return 3;
}
}
I'm making a library application in which the navigation is by tabs, the problem is each time I go from the third tab to the first or the first to the third, the tab content is refreshing, I want to prevent the refresh, Any help please ?
By default, ViewPager
recreates the fragments when you swipe the page. To prevent this, you can try one of three things:
1. In the onCreate()
of your fragments, call setRetainInstance(true)
.
2. If the number of fragments is fixed & relatively small, then in your onCreate()
add the following code:
mViewPager = (ViewPager)findViewById(R.id.pager);
mViewPager.setOffscreenPageLimit(limit); /* limit is a fixed integer*/
3. Use a FragmentPagerAdapter
as part of your ViewPager
.
If I remember correctly, the second option is more promising. But I urge you to try all three and see which of them work.