- A14-Pager ver06
- From Android Template (for now)
- Fragment Pages
- "Modern" Approach -- ViewModel
- Create from "Tabbed Activity"
- activity_main.xml
- fragment_main.xml
- MainActivity.java
- ui/PageViewModel.java
- ui/PlaceholderFragment.java
- ui/SectionsPagerAdapter.java
- Merge with A14-Pager ver04
- activity_main.xml
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/vv_vpViewpager2"
ID change
android:id="@+id/vv_tvTitle"
android:id="@+id/vv_tbTabs"
Remove FAB
- fragment_main.xml
ID change
android:id="@+id/vv_constraintLayout"
android:id="@+id/vv_tvFragLabel"
- strings.xml
<string name="rstr_tab_text_1">Red
<string name="rstr_tab_text_2">Green
<string name="rstr_tab_text_3">Blue
<string name="rstr_tab_text_4">Magenta
- MainActivity.java
public class MainActivity extends AppCompatActivity {
private ActivityMainBinding cv_binding;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
cv_binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(cv_binding.getRoot());
MyPager2Adapter lv_pagerAdapter = new MyPager2Adapter(this);
ViewPager2 lv_viewPager2 = cv_binding.vvVpViewpager2;
lv_viewPager2.setAdapter(lv_pagerAdapter);
TabLayout lv_tabs = cv_binding.vvTbTabs;
new TabLayoutMediator(lv_tabs, lv_viewPager2,
new TabLayoutMediator.TabConfigurationStrategy() {
@Override
public void onConfigureTab(@NonNull TabLayout.Tab tab, int position) {
// instead of tab.setText() at onCreate()
tab.setText(lv_pagerAdapter.cf_getTabTitle(position));
}
}).attach();
}
}
- Change to ui/MyPageViewModel.java
public class MyPageViewModel extends ViewModel {
private MutableLiveData<Integer> mv_mIndex = new MutableLiveData<>();
private LiveData<String> mv_mText = Transformations.map(mv_mIndex, new Function<Integer, String>() {
@Override
public String apply(Integer input) {
return "Page " + input + " is selected";
}
});
public void mf_setIndex(int index) {
mv_mIndex.setValue(index);
}
public LiveData<String> mf_getText() {
return mv_mText;
}
}
- Change to ui/MyPlaceholderFragment.java
public class MyPlaceholderFragment extends Fragment {
// for 'passing intent/fragment parameter' to bundle
private static final String ARG_TAB_NUMBER = "tab_number+1";
private static final String ARG_BG_COLOR = "tab_bgcolor";
private MyPageViewModel cv_pageViewModel;
private FragmentMainBinding cv_binding;
// return MyPlaceholderFragment.newInstance(position + 1);
public static MyPlaceholderFragment cf_newInstance(int index, String bg) {
MyPlaceholderFragment lv_fragment = new MyPlaceholderFragment();
Bundle lv_bundle = new Bundle();
lv_bundle.putInt(ARG_TAB_NUMBER, index);
lv_fragment.setArguments(lv_bundle);
lv_bundle.putString(ARG_BG_COLOR, bg);
lv_fragment.setArguments(lv_bundle);
return lv_fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
cv_pageViewModel = new ViewModelProvider(this).get(MyPageViewModel.class);
int lv_index = 1;
if (getArguments() != null) {
lv_index = getArguments().getInt(ARG_TAB_NUMBER);
}
cv_pageViewModel.mf_setIndex(lv_index);
}
@Override
public View onCreateView(
@NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
cv_binding = FragmentMainBinding.inflate(inflater, container, false);
View lv_root = cv_binding.getRoot();
final TextView lv_textView = cv_binding.vvTvFragLabel;
cv_pageViewModel.mf_getText().observe(getViewLifecycleOwner(), new Observer<String>() {
@Override
public void onChanged(@Nullable String s) {
lv_textView.setText(s);
lv_textView.setTextColor(Color.WHITE);
// tricky -- get color string from MyPager2Adapter->cf_getTabTitle()
if (getArguments() != null) {
String lv_color = getArguments().getString(ARG_BG_COLOR);
lv_root.setBackgroundColor(Color.parseColor(lv_color.toLowerCase()));
//// Alternative approach, define Color[]={Color.RED, ...}
//// Color[ getArguments().getInt(ARG_TAB_NUMBER) ]
}
}
});
return lv_root;
}
@Override
public void onDestroyView() {
super.onDestroyView();
cv_binding = null;
}
}
- Change to ui/MyPager2Adapter.java
import android.content.Context;
import androidx.annotation.StringRes;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;
import com.example.a14_pager.R;
public class MyPager2Adapter extends FragmentStateAdapter {
Context cv_context;
@StringRes
private final int[] TAB_TITLES = new int[]{R.string.rstr_tab_text_1,
R.string.rstr_tab_text_2, R.string.rstr_tab_text_3, R.string.rstr_tab_text_4};
public MyPager2Adapter(FragmentActivity fa) {
super(fa);
cv_context = fa.getApplicationContext();
}
@Override
public Fragment createFragment(int position) {
// [] index from 0, "Page 1-4 is selected"
return MyPlaceholderFragment.cf_newInstance(position+1, cf_getTabTitle(position));
}
@Override
public int getItemCount() {
return TAB_TITLES.length;
}
public String cf_getTabTitle(int position) {
return cv_context.getResources().getString(TAB_TITLES[position]);
}
}
