So recently I'm trying to implement a FAB that will expand into a new activity but it crashes after the FAB was pressed. Moreover from this question where I followed the steps on implementing it: FloatingActionButton expand into a new activity
Logcat:
Process: com.example.jovie.canteen, PID: 6953
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setVisibility(int)' on a null object reference
at com.example.jovie.canteen.Home$1$2.run(Home.java:105)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Home.java
public class Home extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
CoordinatorLayout homeLayout;
private GoogleApiClient client;
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private RevealLayout mRevealLayout;
View mViewToReveal;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
homeLayout = (CoordinatorLayout) findViewById(R.id.CoordinatorLayout);
setSupportActionBar(toolbar);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
mRevealLayout = (RevealLayout) findViewById(R.id.reveal_layout);
final View mRevealView=(View)
findViewById(R.id.reveal_view);
final FloatingActionButton mFab = (FloatingActionButton) findViewById(R.id.fab);
mFab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mFab.setClickable(false); // Avoid naughty guys clicking FAB again and again...
int[] location = new int[2];
mFab.getLocationOnScreen(location);
location[0] += mFab.getWidth() / 2;
location[1] += mFab.getHeight() / 2;
final Intent intent = new Intent(Home.this, SearchActivity.class);
mRevealView.setVisibility(View.VISIBLE);
mRevealLayout.setVisibility(View.VISIBLE);
mRevealLayout.show(location[0], location[1]); // Expand from center of FAB. Actually, it just plays reveal animation.
mFab.postDelayed(new Runnable() {
@Override
public void run() {
startActivity(intent);
/**
* Without using R.anim.hold, the screen will flash because of transition
* of Activities.
*/
overridePendingTransition(0, R.anim.hold);
}
}, 600); // 600 is default duration of reveal animation in RevealLayout
mFab.postDelayed(new Runnable() {
@Override
public void run() {
mFab.setClickable(true);
mRevealLayout.setVisibility(View.INVISIBLE);
mViewToReveal.setVisibility(View.INVISIBLE);
}
}, 960); // Or some numbers larger than 600.
}
});
client = new GoogleApiClient.Builder(Home.this).addApi(AppIndex.API).build();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
activity_home.xml
<com.example.jovie.canteen.RevealLayout
android:id="@+id/reveal_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="invisible">
<View
android:id="@+id/reveal_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="invisible"/>
</com.example.jovie.canteen.RevealLayout>
<include
layout="@layout/app_bar_home"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
android:id="@+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="@layout/nav_header_home"
app:menu="@menu/activity_home_drawer"
android:background="#ffffff" />
However the null on android.view.View.setVisibility(int) is pointing at mViewToReveal.setVisibility(View.INVISIBLE); and not sure where exactly I need to look for, please help.
