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android開發人員請幫忙，我有片段viewpager，當我滑動頁面，併到達最後一頁，然後當我再次返回到第一頁時，第一頁的片段加載其默認display.Please help..here是我在MainActivityViewPager和Android工作室片段
代碼public class MainActivity extends AppCompatActivity {
private ActionBarDrawerToggle actionBarDrawerToggle;
private DrawerLayout drawerLayout;
private ListView navList;
private FragmentManager fragmentManager;
private FragmentTransaction fragmentTransaction;
private ActionBar actionBar;
private ViewPager pager;
private Menu menu;
private float lastTranslate = 0.0f;
private FrameLayout mainframe, galleryframe;
private Frag_Gallery fragGallery;
private Frag_Create fragCreate;
private Frag_Account fragAccount;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pager = (ViewPager) findViewById(R.id.viewPager);
mainframe = (FrameLayout) findViewById(R.id.fragmentholder);
galleryframe = (FrameLayout) findViewById(R.id.galleryholder);
pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
ColorDrawable colorDrawable = new ColorDrawable(Color.parseColor("#0b115e"));
Main_Menu Menu_data[] = new Main_Menu[]
{
new Main_Menu(R.mipmap.gallery_icon, "Gallery"),
new Main_Menu(R.mipmap.create_icon, "Create Your Own"),
new Main_Menu(R.mipmap.account_icon, "My Account"),
new Main_Menu(R.mipmap.contact_icon, "Contact Us")
};
MainMenuAdapter adapter = new MainMenuAdapter(this,
R.layout.listviewmain_item_row, Menu_data);
drawerLayout = (DrawerLayout) findViewById(R.id.drawerlayout);
navList = (ListView) findViewById(R.id.navList);
View header = (View) getLayoutInflater().inflate(R.layout.listviewmain_header_row, null);
navList.addHeaderView(header);
navList.setAdapter(adapter);
navList.setDivider(null);
navList.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
navList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
loadSelection(position);
drawerLayout.closeDrawer(navList);
}
});
actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, R.string.opendrawer, R.string.closedrawer);
drawerLayout.setDrawerListener(actionBarDrawerToggle);
actionBar = getSupportActionBar();
actionBar.setDisplayShowHomeEnabled(true);
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setBackgroundDrawable(colorDrawable);
actionBar.setTitle("");
fragmentManager = getSupportFragmentManager();
loadSelection(0);
pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int pos) {
switch (pos) {
case 0:
menu.getItem(0).setIcon(R.mipmap.gallery_icon);
menu.getItem(1).setIcon(R.mipmap.create_icon_off);
menu.getItem(2).setIcon(R.mipmap.account_icon_off);
break;
case 1:
menu.getItem(0).setIcon(R.mipmap.gallery_icon_off);
menu.getItem(1).setIcon(R.mipmap.create_icon);
menu.getItem(2).setIcon(R.mipmap.account_icon_off);
break;
case 2:
menu.getItem(0).setIcon(R.mipmap.gallery_icon_off);
menu.getItem(1).setIcon(R.mipmap.create_icon_off);
menu.getItem(2).setIcon(R.mipmap.account_icon);
break;
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
this.menu = menu;
getMenuInflater().inflate(R.menu.menu_main, menu);
menu.getItem(0).setIcon(R.mipmap.gallery_icon);
menu.getItem(1).setIcon(R.mipmap.create_icon_off);
menu.getItem(2).setIcon(R.mipmap.account_icon_off);
return true;
}
private void loadSelection(int i) {
switch (i) {
case 1:
actionBar.setTitle("Gallery");
pager.setCurrentItem(0, true);
break;
case 2:
actionBar.setTitle("Design");
pager.setCurrentItem(1, true);
break;
case 3:
actionBar.setTitle("Account");
pager.setCurrentItem(2, true);
break;
case 4:
actionBar.setTitle("Contact us");
break;
default:
actionBar.setTitle("");
break;
}
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
actionBarDrawerToggle.syncState();
}
@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 == android.R.id.home) {
if (drawerLayout.isDrawerOpen(navList)) {
drawerLayout.closeDrawer(navList);
} else {
drawerLayout.openDrawer(navList);
}
}
return super.onOptionsItemSelected(item);
}
private class MyPagerAdapter extends FragmentPagerAdapter {
private Fragment fragment;
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int pos) {
fragment = new Fragment();
switch (pos) {
case 0:
fragment = new Frag_Gallery();
break;
case 1:
fragment = new Frag_Create();
break;
case 2:
fragment = new Frag_Account();
default:
break;
}
return fragment;
}
@Override
public int getCount() {
return 3;
}
}
}
注意：這是viewpager的預期行爲。設置setOffscreenPageLimit會導致更高的內存佔用。如果您希望保存對碎片所做的更改，則需要實施某種存儲解決方案。 – poss