我尝试更改控制台 Firebase 中的数据库，但适配器中的数据未更改，recyclerview 仅在应用程序关闭并再次打开时更改
MainActivity.java
public class MainActivity extends AppCompatActivity {
private List<ModelDB> dbList = new ArrayList<>();
private AdapterDB adapter;
private RecyclerView recyclerView;
FirebaseDatabase database;
DatabaseReference reference;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initFirebase();
getData();
initRecylerView();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main_menu,menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.add_person:
Intent intent = new Intent(getApplicationContext(),RegisterActivity.class);
startActivity(intent);
break;
default:
Toast.makeText(getApplicationContext(),"lalalala",Toast.LENGTH_LONG).show();
break;
}
return super.onOptionsItemSelected(item);
}
private void initFirebase(){
database = FirebaseDatabase.getInstance();
reference = database.getReference("user");
}
private void initRecylerView(){
recyclerView = (RecyclerView)findViewById(R.id.rv_list);
recyclerView.setHasFixedSize(true);
adapter = new AdapterDB(dbList);
recyclerView.setAdapter(adapter);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(layoutManager);
}
private void getData() {
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
//loop data all user
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
//instance object to get and set data
ModelDB modelDB = postSnapshot.getValue(ModelDB.class);
//adding data list from object
dbList.add(modelDB);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
AdapterDB.java
public class AdapterDB extends RecyclerView.Adapter<AdapterDB.MyViewHolder> {
private List<ModelDB> modelDBList;
public AdapterDB(List<ModelDB> modelDBList) {
this.modelDBList = modelDBList;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_data,parent,false);
return new MyViewHolder(view);
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
ModelDB modelDB = modelDBList.get(position);
holder.tv_nama.setText(modelDB.getNama());
holder.tv_alamat.setText(modelDB.getAlamat());
}
@Override
public int getItemCount() {
return modelDBList.size();
}
public class MyViewHolder extends RecyclerView.ViewHolder {
TextView tv_nama, tv_alamat;
public MyViewHolder(View itemView) {
super(itemView);
tv_nama = (TextView) itemView.findViewById(R.id.tv_nama);
tv_alamat = (TextView) itemView.findViewById(R.id.tv_alamat);
}
}
}
最佳答案
您需要让适配器知道数据已更改并且必须刷新 UI 或其他什么。代码中的 OnDataChange 应该是这样的(检查方法中的最后一行) -
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
//loop data all user
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
//instance object to get and set data
ModelDB modelDB = postSnapshot.getValue(ModelDB.class);
//adding data list from object
dbList.add(modelDB);
adapter.notifyDataSetChanged();
}
}
假设代码的其他部分没有其他错误，这应该可以解决问题
关于java - 为什么实时数据库无法在我的 recyclerview 中工作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/42184179/