我使用viewpager创建了一个新的android studio选项卡式活动，但是这三个选项卡是shwoinf，我在这里放入片段的相同内容是我的类
package com.mrad4tech.development.tabbedactivity;
import java.util.Locale;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.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;
public class MainActivity2Activity extends ActionBarActivity 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;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity2);
// Set up the action bar.
final ActionBar actionBar = getSupportActionBar();
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(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++) {
// 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.menu_main_activity2, 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();
//noinspection SimplifiableIfStatement
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_main_activity2, container, false);
return rootView;
}
}
}
fragment_main_activity2：是片段的名称
答案 0 :(得分：3)
我不确定我是否正确理解了这个问题。
这是你在某处复制的一段代码吗？你想知道你应该在哪里改变以显示不同的片段？
如果你想要显示3个完全不同的片段，你必须将SectionsPageAdapter.getItem(int position)改为这样的
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
switch (position) {
case 0:
return FragmentFirst.newInstance();
case 1:
return FragmentSecond.newInstance();
case 2:
return FragmentThird.newInstance();
default:
//assume you only have 3
throw new IllegalArgumentException();
}
}
并创建Fragment类，并记得创建相应的布局xml，即fragment_first.xml，fragment_second.xml，fragment_third.xml
public static class FragmentFirst extends Fragment {
public static FragmentFirst newInstance(int sectionNumber) {
FragmentFirst fragment = new FragmentFirst();
return fragment;
}
public FragmentFirst() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_first, container, false);
return rootView;
}
}
public static class FragmentSecond extends Fragment {
public static FragmentSecond newInstance(int sectionNumber) {
FragmentSecond fragment = new FragmentSecond();
return fragment;
}
public FragmentSecond() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_second, container, false);
return rootView;
}
}
public static class FragmentThird extends Fragment {
public static FragmentThird newInstance(int sectionNumber) {
FragmentThird fragment = new FragmentThird();
return fragment;
}
public FragmentThird() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_third, container, false);
return rootView;
}
}
编辑整个SectionsPagerAdapter以供参考
/**
* 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.
switch (position) {
case 0:
return FragmentFirst.newInstance();
case 1:
return FragmentSecond.newInstance();
case 2:
return FragmentThird.newInstance();
default:
//assume you only have 3
throw new IllegalArgumentException();
}
}
@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;
}
}
答案 1 :(得分：1)
您需要将PlaceholderFragment更改为以下内容。
public static class PlaceholderFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
// A field that contains your args value;
private int mSectionNumber;
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 void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Parses your arguments
if(getArguments() != null) {
mSectionNumber = getArguments().getInt(ARG_SECTION_NUMBER);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_activity2, container, false);
return rootView;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
// Updates your view
((TextView) findViewById(R.id.text1)).setText("Section Number: " + mSectionNumber);
}
}