FirebaseRecyclerAdapter
- populateViewHolder
第一次运行时没有填充数据,但是当我关闭应用并打开它时,数据会绑定在RecyclerView
View Holder中。
我不知道为什么数据第一次没有填充,它显示空白屏幕
这是我的MainActivity
mDatabase = FirebaseDatabase.getInstance().getReference();
// [END create_database_reference]
mRecycler = (RecyclerView) findViewById(R.id.recycler_view);
mRecycler.setHasFixedSize(true);
setSupportActionBar(toolbar);
final LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
layoutManager.setReverseLayout(true);
layoutManager.setStackFromEnd(true);
mRecycler.setLayoutManager(layoutManager);
// Set up FirebaseRecyclerAdapter with the Query
//Query postsQuery = mDatabase.child("EN").child("Courses") ;
DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("EN").child("Courses");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Toast.makeText(MainActivity.this, dataSnapshot.toString(), Toast.LENGTH_SHORT).show();
}
@Override
public void onCancelled(DatabaseError databaseError) {
Toast.makeText(MainActivity.this, databaseError.toString(), Toast.LENGTH_SHORT).show();
}
});
Log.d("ref", String.valueOf(ref));
// Log.d("Query", String.valueOf(postsQuery));
mAdapter = new FirebaseRecyclerAdapter<Course, CourseViewHolder>(Course.class, R.layout.item_home,
CourseViewHolder.class, ref) {
@Override
protected void populateViewHolder(final CourseViewHolder viewHolder, final Course model, final int position) {
viewHolder.bindToPost(model);
}
};
mRecycler.setAdapter(mAdapter);
ViewHolder
public class CourseViewHolder extends RecyclerView.ViewHolder {
public TextView titleView;
public TextView descriptionView;
public ImageView IconView;
public TextView lessonCountView;
public CourseViewHolder(View itemView) {
super(itemView);
titleView = (TextView) itemView.findViewById(R.id.title);
descriptionView = (TextView) itemView.findViewById(R.id.description);
//IconView = (ImageView) itemView.findViewById(R.id.star);
}
public void bindToPost(Course post) {
// Log.d("Post", String.valueOf(post));
titleView.setText(post.getName());
descriptionView.setText(post.getDescription());
}
}
我的模型Pojo
public class Course {
public String description;
public String title;
public Course() {
// Default constructor required for calls to DataSnapshot.getValue(Post.class)
}
public Course(String title, String description) {
// this.description = author;
this.title = title;
this.description =description;
}
public String getName() {
return title;
}
public String getDescription() {
return description;
}
}
答案 0 :(得分:3)
找到解决方案。
问题是RecyclerView
的高度为wrap_content
。因此,请确保RecyclerView
高度设置为match_parent
。这将解决这个问题。
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical" />
答案 1 :(得分:2)
如果您不想使用match_parent
,则不应致电mRecycler.setHasFixedSize(true);