我的应用运行没有错误但没有检索数据。它显示一个空屏幕。 在我的XML文件中有一些错误，这些都不妨碍我吗？ 因此，当我运行应用程序时，它不会从数据库中检索数据。 我需要创建另一个类吗？ 这是我的代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.food.sheenishere.stark.profilemain">
<FrameLayout
android:id="@+id/content"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1">
<ListView
android:id="@+id/listview"
style="@style/Widget.AppCompat.ListView"
android:layout_width="wrap_content"
android:layout_height="match_parent" />
</FrameLayout>
<android.support.design.widget.BottomNavigationView
android:id="@+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="?android:attr/windowBackground"
app:menu="@menu/navigation" />
</LinearLayout>
my java code
public class profilemain extends AppCompatActivity {
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthListener;
private Firebase mref;
private ListView mlistview;
ArrayList<String> arrayList=new ArrayList<>();
ArrayAdapter<String> arrayAdapter;
private BottomNavigationView.OnNavigationItemSelectedListener
mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
Toast.makeText(profilemain.this,"hi
hello",Toast.LENGTH_SHORT).show();
return true;
case R.id.navigation_dashboard:
Toast.makeText(profilemain.this,"hi hello",Toast.LENGTH_SHORT).show();
return true;
case R.id.navigation_notifications:
Toast.makeText(profilemain.this,"hi hello",Toast.LENGTH_SHORT).show();
return true;
case R.id.navigation_signout:
Toast.makeText(profilemain.this,"You have successfully
Signed out",Toast.LENGTH_SHORT).show();
mAuth.signOut();
return true;
}
return false;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profilemain);
mlistview=(ListView) findViewById(R.id.listview);
Firebase.setAndroidContext(this);
mref=new Firebase("https://stark-1dffd.firebaseio.com/users");
arrayAdapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,arrayList);
mlistview.setAdapter(arrayAdapter);
mref.addChildEventListener(new com.firebase.client.ChildEventListener() {
@Override
public void onChildAdded(com.firebase.client.DataSnapshot dataSnapshot, String s) {
String value=dataSnapshot.getValue(String.class);
arrayList.add(value);
arrayAdapter.notifyDataSetChanged();
}
@Override
public void onChildChanged(com.firebase.client.DataSnapshot
dataSnapshot, String s) {
}
@Override
public void onChildRemoved(com.firebase.client.DataSnapshot
dataSnapshot) {
}
@Override
public void onChildMoved(com.firebase.client.DataSnapshot
dataSnapshot, String s) {
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});
BottomNavigationView navigation = (BottomNavigationView)
findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener
(mOnNavigationItemSelectedListener
);
mAuth=FirebaseAuth.getInstance();
mAuthListener =new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
if (firebaseAuth.getCurrentUser()==null){
startActivity(new
Intent(profilemain.this,MainActivity.class));
}
}
};
}
@Override
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
}
}