我已经阅读了有关此主题的所有stackOverflow答案，其中任何一个都适合我，或者我无法自己制作。
正如您在下面的代码中看到的，我从Android Studio添加了默认的ViewPager活动，现在我需要添加新页面或从相应的按钮中删除现有页面。
因此，活动正确加载并获得正确的页数，我也可以成功更改每个页面中的信息。正如您所看到的，应用程序已连接到Firebase，我从那里获得了我的活动应该具有的总页数（狗），这很有效。
现在，如何添加新页面，移至该页面以及更新适配器和总页数？
删除相同，如何删除当前页面，然后移动到另一个页面并更新适配器没有问题？
我对此感到非常疯狂，花了一整天的时间在stackoverflow中找到了不同的解决方案，但却无法实现。我现在很困惑何时使用＆＃34; notifyDataSetChanged（）＆＃34;，如果这是一个好主意，则覆盖＆＃34; getItemPosition＆＃34;或不，等等。
如果有人能够帮我调整我的项目的答案，我会很感激，它是默认的ViewPager，只是修改了小部件以尝试解决它，但不知道我还能做些什么。
提前谢谢你，对不起我的英语。
注意：某些功能如＆＃34; updateIntValueFromCurrentUser（）＆＃34;在MainActivity中声明但是有效，它们与firebase查询等有关，所以我不关注它。
public class DummyViewPagerActivity extends MainActivity {
/**
* 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}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
private static ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dummy_view_pager);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// 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.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
//Creating menu bar
@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_dummy_view_pager, menu);
return true;
}
//Creating the two buttons to save and delete the images
@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.
switch (item.getItemId()) {
case R.id.add:
updateIntValueFromCurrentUser("dogs_number", person.getDogs_number()+1);
return true;
case R.id.edit:
return true;
case R.id.delete:
updateIntValueFromCurrentUser("dogs_number", person.getDogs_number()-1);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/**
* 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";
public PlaceholderFragment() {
}
/**
* 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;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = null;
try {
rootView = inflater.inflate(R.layout.fragment_dummy_view_pager, container, false);
TextView dogName = (TextView) rootView.findViewById(R.id.dog_name);
dogName.setText(allDogs.get((getArguments().getInt(ARG_SECTION_NUMBER)) - 1).getName());
} catch (Exception e) {
Log.e("RaisedException()", e.getMessage());
}
return rootView;
}
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentStatePagerAdapter {
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 getItemPosition(Object object) {
// POSITION_NONE makes it possible to reload the PagerAdapter
return POSITION_NONE;
}
@Override
public int getCount() {
// Show x total pages.
return person.getDogs_number();
}
@Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}
答案 0 :(得分：1)
从FragmentViewPager添加/删除项目有点棘手：
尝试使用此适配器，让我知道它是否适合您。
enter code here
public class Emp4 {
private JFrame frame;
private JTextField jtxtName;
private JTextField jtxtAge;
private JTextField jtxtSal;
private JTextField jtxtHour_Pay;
private JTextField jtxtHour_Worked;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Emp4 window = new Emp4();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Emp4() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(0, 0, 1000, 800);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JPanel panel = new JPanel();
panel.setBorder(new LineBorder(new Color(0, 0, 0), 3));
panel.setBounds(30, 11, 414, 36);
frame.getContentPane().add(panel);
panel.setLayout(null);
JLabel lblEmployeeDatabase = new JLabel("Employee Database");
lblEmployeeDatabase.setFont(new Font("Tahoma", Font.PLAIN, 15));
lblEmployeeDatabase.setBounds(157, 7, 193, 25);
panel.add(lblEmployeeDatabase);
JPanel panel_1 = new JPanel();
panel_1.setBorder(new LineBorder(new Color(0, 0, 0), 3));
panel_1.setBounds(10, 61, 464, 230);
frame.getContentPane().add(panel_1);
panel_1.setLayout(null);
JLabel jlblEmpName = new JLabel("Employee Name");
jlblEmpName.setBounds(10, 11, 110, 14);
panel_1.add(jlblEmpName);
jtxtName = new JTextField();
jtxtName.setBounds(114, 8, 120, 20);
panel_1.add(jtxtName);
jtxtName.setColumns(10);
JLabel jlblEmpAge = new JLabel("Employee Age");
jlblEmpAge.setBounds(10, 52, 110, 14);
panel_1.add(jlblEmpAge);
jtxtAge = new JTextField();
jtxtAge.setColumns(10);
jtxtAge.setBounds(114, 49, 120, 20);
panel_1.add(jtxtAge);
JLabel jlblEmpType = new JLabel("Employee Type");
jlblEmpType.setBounds(10, 95, 110, 14);
panel_1.add(jlblEmpType);
JRadioButton jrdbuttonFullTime = new JRadioButton("Full Time");
JRadioButton jrdbtnContract = new JRadioButton("Contract ");
JLabel jlblEmpHour = new JLabel("Hourly Rate");
jlblEmpHour.setBounds(5, 121, 66, 14);
ButtonGroup group =new ButtonGroup();
JLabel jlblEmpSal = new JLabel("Salary");
jlblEmpSal.setBounds(114, 121, 66, 14);
JLabel jlblEmpWork = new JLabel("Hours Worked");
jlblEmpWork.setBounds(150, 120, 86, 24);
jtxtSal = new JTextField();
jtxtSal.setColumns(10);
jtxtSal.setBounds(164, 121, 109, 23);
jtxtHour_Pay = new JTextField();
jtxtHour_Pay.setColumns(10);
jtxtHour_Pay.setBounds(75, 121, 59, 23);
jtxtHour_Worked = new JTextField();
jtxtHour_Worked.setColumns(10);
jtxtHour_Worked.setBounds(243, 121, 109, 23);
group.add(jrdbuttonFullTime);
group.add(jrdbtnContract);
jrdbuttonFullTime.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(jrdbuttonFullTime.isSelected()){
//jrdbtnContract.setSelected(false);
panel_1.add(jlblEmpSal);
panel_1.add(jtxtSal);
jlblEmpHour.setVisible(false);
jtxtHour_Pay.setVisible(false);
jtxtHour_Worked.setVisible(false);
jlblEmpWork.setVisible(false);
}
}
});
jrdbuttonFullTime.setBounds(113, 91, 109, 23);
panel_1.add(jrdbuttonFullTime);
jrdbtnContract.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(jrdbtnContract.isSelected()){
//jrdbuttonFullTime.setSelected(false);
panel_1.add(jlblEmpHour);
panel_1.add(jtxtHour_Pay);
panel_1.add(jlblEmpWork);
panel_1.add(jtxtHour_Worked);
jlblEmpSal.setVisible(false);
jtxtSal.setVisible(false);
}
}
});
jrdbtnContract.setBounds(218, 91, 109, 23);
panel_1.add(jrdbtnContract);
}
}