1 package com.example.android.horizontalpaging; 2 3 import android.app.ActionBar; 4 import android.app.FragmentTransaction; 5 import android.os.Bundle; 6 import android.support.v4.app.Fragment; 7 import android.support.v4.app.FragmentActivity; 8 import android.support.v4.app.FragmentManager; 9 import android.support.v4.app.FragmentPagerAdapter; 10 import android.support.v4.view.ViewPager; 11 import android.view.LayoutInflater; 12 import android.view.View; 13 import android.view.ViewGroup; 14 import android.widget.TextView; 15 16 import java.util.Locale; 17 18 public class MainActivity extends FragmentActivity implements ActionBar.TabListener { 19 20 /** 21 * The {@link android.support.v4.view.PagerAdapter} that will provide 22 * fragments for each of the sections. We use a 23 * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which 24 * will keep every loaded fragment in memory. If this becomes too memory 25 * intensive, it may be best to switch to a 26 * {@link android.support.v4.app.FragmentStatePagerAdapter}. 27 */ 28 SectionsPagerAdapter mSectionsPagerAdapter; 29 30 /** 31 * The {@link ViewPager} that will host the section contents. 32 */ 33 ViewPager mViewPager; 34 35 /** 36 * Create the activity. Sets up an {@link android.app.ActionBar} with tabs, and then configures the 37 * {@link ViewPager} contained inside R.layout.activity_main. 38 * 39 * <p>A {@link SectionsPagerAdapter} will be instantiated to hold the different pages of 40 * fragments that are to be displayed. A 41 * {@link android.support.v4.view.ViewPager.SimpleOnPageChangeListener} will also be configured 42 * to receive callbacks when the user swipes between pages in the ViewPager. 43 * 44 * @param savedInstanceState 45 */ 46 @Override 47 protected void onCreate(Bundle savedInstanceState) { 48 super.onCreate(savedInstanceState); 49 // Load the UI from res/layout/activity_main.xml 50 setContentView(R.layout.sample_main); 51 52 // Set up the action bar. The navigation mode is set to NAVIGATION_MODE_TABS, which will 53 // cause the ActionBar to render a set of tabs. Note that these tabs are *not* rendered 54 // by the ViewPager; additional logic is lower in this file to synchronize the ViewPager 55 // state with the tab state. (See mViewPager.setOnPageChangeListener() and onTabSelected().) 57 final ActionBar actionBar = getActionBar(); 58 actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 60 62 // Create the adapter that will return a fragment for each of the three primary sections 63 // of the app. 64 mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); 65 66 // Set up the ViewPager with the sections adapter. 67 mViewPager = (ViewPager) findViewById(R.id.pager); 68 mViewPager.setAdapter(mSectionsPagerAdapter); 70 71 // When swiping between different sections, select the corresponding tab. We can also use 72 // ActionBar.Tab#select() to do this if we have a reference to the Tab. 74 mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { 75 @Override 76 public void onPageSelected(int position) { 77 actionBar.setSelectedNavigationItem(position); 78 } 79 }); 81 83 // For each of the sections in the app, add a tab to the action bar. 84 for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) { 85 // Create a tab with text corresponding to the page title defined by the adapter. Also 86 // specify this Activity object, which implements the TabListener interface, as the 87 // callback (listener) for when this tab is selected. 88 actionBar.addTab( 89 actionBar.newTab() 90 .setText(mSectionsPagerAdapter.getPageTitle(i)) 91 .setTabListener(this)); 92 } 94 } 95 96 /** 97 * Update {@link ViewPager} after a tab has been selected in the ActionBar. 98 * 99 * @param tab Tab that was selected. 100 * @param fragmentTransaction A {@link android.app.FragmentTransaction} for queuing fragment operations to 101 * execute once this method returns. This FragmentTransaction does 102 * not support being added to the back stack. 103 */ 105 @Override 106 public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) { 107 // When the given tab is selected, tell the ViewPager to switch to the corresponding page. 108 mViewPager.setCurrentItem(tab.getPosition()); 109 } 111 112 /** 113 * Unused. Required for {@link android.app.ActionBar.TabListener}. 114 */ 115 @Override 116 public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) { 117 } 118 119 /** 120 * Unused. Required for {@link android.app.ActionBar.TabListener}. 121 */ 122 @Override 123 public void onTabReselected(ActionBar.Tab tab, FragmentTransa ction fragmentTransaction) { 124 } 125 127 /** 128 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to 129 * one of the sections/tabs/pages. This provides the data for the {@link ViewPager}. 130 */ 131 public class SectionsPagerAdapter extends FragmentPagerAdapter { 133 134 public SectionsPagerAdapter(FragmentManager fm) { 135 super(fm); 136 } 137 139 /** 140 * Get fragment corresponding to a specific position. This will be used to populate the 141 * contents of the {@link ViewPager}. 142 * 143 * @param position Position to fetch fragment for. 144 * @return Fragment for specified position. 145 */ 146 @Override 147 public Fragment getItem(int position) { 148 // getItem is called to instantiate the fragment for the given page. 149 // Return a DummySectionFragment (defined as a static inner class 150 // below) with the page number as its lone argument. 151 Fragment fragment = new DummySectionFragment(); 152 Bundle args = new Bundle(); 153 args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1); 154 fragment.setArguments(args); 155 return fragment; 156 } 158 160 /** 161 * Get number of pages the {@link ViewPager} should render. 162 * 163 * @return Number of fragments to be rendered as pages. 164 */ 165 @Override 166 public int getCount() { 167 // Show 3 total pages. 168 return 3; 169 } 171 173 /** 174 * Get title for each of the pages. This will be displayed on each of the tabs. 175 * 176 * @param position Page to fetch title for. 177 * @return Title for specified page. 178 */ 179 @Override 180 public CharSequence getPageTitle(int position) { 181 Locale l = Locale.getDefault(); 182 switch (position) { 183 case 0: 184 return getString(R.string.title_section1).toUpperCase(l); 185 case 1: 186 return getString(R.string.title_section2).toUpperCase(l); 187 case 2: 188 return getString(R.string.title_section3).toUpperCase(l); 189 } 190 return null; 191 } 193 } 194 195 /** 196 * A dummy fragment representing a section of the app, but that simply displays dummy text. 197 * This would be replaced with your application's content. 198 */ 199 public static class DummySectionFragment extends Fragment { 200 /** 201 * The fragment argument representing the section number for this 202 * fragment. 203 */ 204 public static final String ARG_SECTION_NUMBER = "section_number"; 205 206 public DummySectionFragment() { 207 } 208 209 @Override 210 public View onCreateView(LayoutInflater inflater, ViewGroup container, 211 Bundle savedInstanceState) { 212 View rootView = inflater.inflate(R.layout.fragment_main_dummy, container, false); 213 TextView dummyTextView = (TextView) rootView.findViewById(R.id.section_label); 214 dummyTextView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER))); 215 return rootView; 216 } 217 } 218 219 }