碎片重新初始化初始选项卡上的内容 - ANDROID(Fragments Re-Initializing content on Initial tab selection - ANDROID)

 我有一个应用程序使用ViewPager作为TabHost。 问题是，当应用程序启动时，全部显示正常，在所有3个选项卡之间滑动。 
 
 但是，重新选择第一个选项卡后，应用程序会重新初始化，但不会显示正确的内容，应用程序应该保留碎片当前状态而不是重新初始化。 
 
 码： 
 
 
 
 TabAdapter.java 
 
 
public class TabAdapter extends FragmentPagerAdapter{


public TabAdapter(FragmentManager fm) {
    super(fm);
}

@Override
public Fragment getItem(int position) {

    switch(position){
        case 0:
            return new MapFragmentView();
        case 1:
            return new LogView();
        case 2:
            return new SettingsView();
    }

    return null;
}

@Override
public int getCount() {
    return 3;
}
 
 } 
 
 
 
 MapsActivity.java（主要活动） 
 
 
public class MapsActivity extends FragmentActivity implements ActionBar.TabListener {

private ViewPager viewPage;
private TabAdapter myAdapter;
private ActionBar actionBar;
public static FragmentManager fragmentManager;

private String[] tabNames = {"Map", "Log" , "Settings"};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);

    fragmentManager = getFragmentManager();

    viewPage = (ViewPager) findViewById(R.id.pager);
    actionBar = getActionBar();
    myAdapter = new TabAdapter(getSupportFragmentManager());

    viewPage.setAdapter(myAdapter);
    actionBar.setHomeButtonEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Adding Tabs
    for (String tab_name : tabNames) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                .setTabListener(this));
    }

    viewPage.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 onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
    viewPage.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {

}

@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
    viewPage.setCurrentItem(tab.getPosition());
}
}
 
 初始视图： 
 
  
 
 重新选择地图后的实际结果标签： 
 
  
 
 预期结果： 
 
  
 
 
 我知道在TabAdapter文件中，每次调用getPosition时都会创建新实例，所以这可能是问题所在。 
 
 任何帮助将不胜感激！ 

I have an application that is using a ViewPager that acts as a TabHost. The issue is, when the application launches, all displays fine, swiping between all 3 tabs. 
 
However upon reselecting the 1st tab, the application gets reinitialized but does not display the correct content, the app should retain the Fragments current state instead of Re-initializing.
 
Code:
 
 
 
TabAdapter.java
 
 
public class TabAdapter extends FragmentPagerAdapter{


public TabAdapter(FragmentManager fm) {
    super(fm);
}

@Override
public Fragment getItem(int position) {

    switch(position){
        case 0:
            return new MapFragmentView();
        case 1:
            return new LogView();
        case 2:
            return new SettingsView();
    }

    return null;
}

@Override
public int getCount() {
    return 3;
}
 
}
 
 
 
MapsActivity.java (Main Activity)
 
 
public class MapsActivity extends FragmentActivity implements ActionBar.TabListener {

private ViewPager viewPage;
private TabAdapter myAdapter;
private ActionBar actionBar;
public static FragmentManager fragmentManager;

private String[] tabNames = {"Map", "Log" , "Settings"};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);

    fragmentManager = getFragmentManager();

    viewPage = (ViewPager) findViewById(R.id.pager);
    actionBar = getActionBar();
    myAdapter = new TabAdapter(getSupportFragmentManager());

    viewPage.setAdapter(myAdapter);
    actionBar.setHomeButtonEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Adding Tabs
    for (String tab_name : tabNames) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                .setTabListener(this));
    }

    viewPage.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 onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
    viewPage.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {

}

@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
    viewPage.setCurrentItem(tab.getPosition());
}
}
 
Initial View :
 
 
Actual Result after Re-selecting Maps Tab:
 
 
Expected Result:
 
 
 
I understand that in the TabAdapter file, we are creating New Instances everytime the getPosition is called, so that might be the issue. 
 
Any help will be greatly appreciated!

原文：https://stackoverflow.com/questions/31806420