Ich habe eine FloatingActionButton
innerhalb Mai activity_main.xml
Layout, das fabBtn
genannt wird.Verstecke eine Floating Action Button eines anderen Layouts
Meine Anwendung ist integriert mit einem ViewPager
und drei Fragment
s.I wollen die FloatingActionButton
verstecken, wenn mein erstes Fragment
eine Rolle erkennt, aber ich halte eine NullPointerException
bekommen, wenn der Benutzer Scrollen beginnt.
Ich glaube, es könnte sein, dass mein Fragment die FloatingActionButton
aus dem activity_main.xml
Layout nicht bekommen kann?
Hier ist meine activity_main.xml
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/rootLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="lh.com.newme.MainActivity"
xmlns:fab="http://schemas.android.com/tools">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:layout_scrollFlags="scroll|snap"/>
<android.support.design.widget.TabLayout
android:id="@+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:tabMode="fixed"
app:layout_scrollFlags="snap|enterAlways"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
android:background="#ffffff" />
<android.support.design.widget.FloatingActionButton
android:id="@+id/fabBtn"
android:layout_marginBottom="@dimen/codelab_fab_margin_bottom"
android:layout_marginRight="@dimen/codelab_fab_margin_right"
android:layout_width="wrap_content"
fab:fab_type="normal"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
app:backgroundTint="@color/fab_ripple_color"
android:src="@drawable/ic_plus"
app:fabSize="normal"
/>
</android.support.design.widget.CoordinatorLayout>
Hier ist meine erste Fragment
aus, wo ich will die FloatingActionButton
verstecken:
public class Ernaehrung extends Fragment {
NestedScrollView nsv;
FloatingActionButton fab;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setHasOptionsMenu(true);
final View rootView = inflater.inflate(R.layout.ernaehrung, container, false);
Button Fruehstuck = (Button) rootView.findViewById(R.id.fruehstuck);
Button Mittagessen = (Button) rootView.findViewById(R.id.mittagessen);
Button Snacks = (Button) rootView.findViewById(R.id.snacks);
Fruehstuck.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent FruehstuckScreen = new Intent(getActivity(), lh.com.newme.Fruehstuck.class);
startActivity(FruehstuckScreen);
}
});
Mittagessen.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent MittagScreen = new Intent(getActivity(), lh.com.newme.Mittagessen.class);
startActivity(MittagScreen);
}
});
Snacks.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent SnackScreen = new Intent(getActivity(), lh.com.newme.Snacks.class);
startActivity(SnackScreen);
}
});
nsv = (NestedScrollView)rootView.findViewById(R.id.Nsv);
fab = (FloatingActionButton)rootView.findViewById(R.id.fabBtn);
nsv.setOnScrollChangeListener(new NestedScrollView.OnScrollChangeListener() {
@Override
public void onScrollChange(NestedScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
if (oldScrollY < scrollY){
fab.hide();
}
else
fab.show();}
});
return rootView;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
menu.clear();
inflater.inflate(R.menu.main_menu_ernaehrung, menu);
super.onCreateOptionsMenu(menu, inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
int id = item.getItemId();
if (id == R.id.benutzer){
}
return super.onOptionsItemSelected(item);
}
}
Das ist mein MainActivity.class
:
public class MainActivity extends AppCompatActivity {
FloatingActionButton fabBtn;
CoordinatorLayout rootLayout;
Toolbar toolbar;
TabLayout tabLayout;
...
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
viewPager.setAdapter(new SampleFragmentPagerAdapter(getSupportFragmentManager()));
viewPager.setOffscreenPageLimit(2);
// Give the TabLayout the ViewPager
final TabLayout tabLayout = (TabLayout) findViewById(R.id.tabLayout);
tabLayout.setupWithViewPager(viewPager);
final FloatingActionButton fab = (FloatingActionButton)findViewById(R.id.fabBtn);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
switch (position) {
case 0:
fab.show();
...
break;
case 1:
fab.show();
...
break;
case 2:
fab.hide();
break;
default:
fab.hide();
break;
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
initInstances();
}
private void initInstances() {
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setHomeButtonEnabled(true);
rootLayout = (CoordinatorLayout) findViewById(R.id.rootLayout);
fabBtn = (FloatingActionButton) findViewById(R.id.fabBtn);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main_menu_edit, 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.einstellungen) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
Dank Mann, es hat funktioniert! – Dolan
nicht die erste Lösung, aber die Lösung funktioniert. –
Ich mag zweite Lösung ... arbeitete wie Bingo..danke – Ujjwal