Here is main activity layout XML
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="fill_parent">
<LinearLayout
android:id="@+id/left"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
<android.support.v4.view.ViewPager
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="0dip"
android:layout_height="fill_parent"
android:layout_toLeftOf="@+id/left"
android:layout_toRightOf="@+id/right"
tools:context=".MainActivity" />
<LinearLayout
android:id="@+id/right"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentRight="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
</RelativeLayout>
Fragment Layout XML :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" android:orientation="horizontal"
tools:context=".DummySectionFragment" android:background="@color/gray">
<TextView
android:id="@+id/section_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
Main Activity :
package com.example.androidtest;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.view.Menu;
public class MainActivity 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.new_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 three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager(), getApplicationContext());
// 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.main, 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) {
}
}
Fragment :
package com.example.androidtest;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.TextView;
/**
* A dummy fragment representing a section of the app, but that simply
* displays dummy text.
*/
public class DummySectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public DummySectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_dummy,
container, false);
TextView dummyTextView = (TextView) rootView
.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
return rootView;
}
}
Pager Adapter :
package com.example.androidtest;
import java.util.Locale;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
private Context context;
public SectionsPagerAdapter(FragmentManager fm, Context context) {
super(fm);
this.context = context;
}
@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 = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
}
@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 context.getString(R.string.title_section1).toUpperCase(l);
case 1:
return context.getString(R.string.title_section2).toUpperCase(l);
case 2:
return context.getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
Expected : 2 red bars on both sides. ViewPager in the middle.
Whats happening : 2 red bars on both sides. Blank in the middle.
Question : Why ?
EDIT :
I modified the main activity layout XML to the following to get this to work.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="fill_parent">
<LinearLayout
android:id="@+id/left"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
<android.support.v4.view.ViewPager
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
tools:context=".MainActivity" android:layout_toRightOf="@+id/left"/>
<LinearLayout
android:id="@+id/right"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentRight="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
</RelativeLayout>
Only change is I removed android:layout_toRightOf="@+id/right"
and changed layout_width="fill_parent". Fill_parent I understand. By why does removing the other make a difference ?
You have to do two things in main.xml:
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