我正在開發 RecyclerView 并使用 CustomAdapter 并且我的應用程序運行順利，但我的 ListView 沒有顯示它的內容！我的代碼有什么遺漏或錯誤？我試圖返回 arraylist.size() 并輸入 list.setHasFixedSize 并沒有工作！潛在所有者_listview.java（活動類）public class prospectowner_listview extends AppCompatActivity { RecyclerView list; ArrayList <com.example.android.e7gzlykora.owner> ownerlist = new ArrayList <>(); private DatabaseReference mFirebaseDatabase; private FirebaseDatabase mFirebaseInstance; owner owner; customAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.prospectowner_listview); list = findViewById(R.id.list); LinearLayoutManager manager = new LinearLayoutManager(this); list.setLayoutManager(manager); list.setHasFixedSize(true); manager.setOrientation(LinearLayoutManager.VERTICAL); adapter = new customAdapter(prospectowner_listview.this,ownerlist); mFirebaseInstance = FirebaseDatabase.getInstance(); mFirebaseDatabase = mFirebaseInstance.getReference("owners"); mFirebaseDatabase.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(@NonNull DataSnapshot dataSnapshot) { for (DataSnapshot data: dataSnapshot.getChildren()){ owner o = data.getValue(owner.class); ownerlist.add(o); } list.setAdapter(adapter); } @Override public void onCancelled(@NonNull DatabaseError databaseError) { } }); }}客戶適配器.javapublic class customAdapter extends RecyclerView.Adapter<customAdapter.MyViewHolder>{ private final ArrayList<owner> ownerlist; private final Context mContext; public customAdapter(Context c , ArrayList<owner> p) { this.mContext = c; this.ownerlist = new ArrayList <>(); }
4 回答
紅顏莎娜
TA貢獻1842條經驗 獲得超13個贊
我認為問題來自您的適配器，請更改您的適配器代碼，如下所示：
public class customAdapter extends RecyclerView.Adapter<customAdapter.MyViewHolder>{
private ArrayList<owner> ownerlist;
private Context mContext;
public customAdapter(Context c , ArrayList<owner> p) {
this.mContext = c;
this.ownerlist = p;
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int
viewType) {
return new MyViewHolder(LayoutInflater.from(mContext).inflate(R.layout.prospectowners,parent,false));
}
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
owner owner = ownerlist.get(position);
holder.name.setText(owner.getName());
holder.field.setText(owner.getFieldname());
holder.mobile.setText(owner.getMobile());
holder.address.setText(owner.getAddress());
holder.cost.setText(owner.getCost());
}
@Override
public int getItemCount() {
return ownerlist.size();
}
public void addData(ArrayList<owner> newData){
this.ownerlist.addAll(newData);
notifyOnDataSetChanged();
}
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView name;
public TextView field;
public TextView mobile;
public TextView address;
public TextView cost;
public MyViewHolder(View itemView) {
super(itemView);
this.name = itemView.findViewById(R.id.name);
this.field = itemView.findViewById(R.id.fieldName);
this.mobile = itemView.findViewById(R.id.mobileowner);
this.address = itemView.findViewById(R.id.address);
this.cost = itemView.findViewById(R.id.cost);
}
}
}
然后像這樣調用方法addData：
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot data: dataSnapshot.getChildren()){
owner o = data.getValue(owner.class);
ownerlist.add(o);
}
list.setAdapter(adapter);
adapter.addData(ownerlist);
}
順便說一句，實際上您可以在偵聽器之外設置適配器
UPDATE（此更新設置適配器值的位置默認為空數據，然后在監聽觸發時填充）
public class customAdapter extends RecyclerView.Adapter<customAdapter.MyViewHolder>{
private ArrayList<owner> ownerlist;
private Context mContext;
public customAdapter(Context c , ArrayList<owner> p) {
this.mContext = c;
this.ownerlist = new Arraylist<>();
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int
viewType) {
return new MyViewHolder(LayoutInflater.from(mContext).inflate(R.layout.prospectowners,parent,false));
}
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
owner owner = ownerlist.get(position);
holder.name.setText(owner.getName());
holder.field.setText(owner.getFieldname());
holder.mobile.setText(owner.getMobile());
holder.address.setText(owner.getAddress());
holder.cost.setText(owner.getCost());
}
@Override
public int getItemCount() {
return ownerlist.size();
}
public void addData(ArrayList<owner> newData){
this.ownerlist.addAll(newData);
notifyOnDataSetChanged();
}
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView name;
public TextView field;
public TextView mobile;
public TextView address;
public TextView cost;
public MyViewHolder(View itemView) {
super(itemView);
this.name = itemView.findViewById(R.id.name);
this.field = itemView.findViewById(R.id.fieldName);
this.mobile = itemView.findViewById(R.id.mobileowner);
this.address = itemView.findViewById(R.id.address);
this.cost = itemView.findViewById(R.id.cost);
}
}
}
public class prospectowner_listview extends AppCompatActivity {
RecyclerView list;
ArrayList <com.example.android.e7gzlykora.owner> ownerlist = new ArrayList <>();
private DatabaseReference mFirebaseDatabase;
private FirebaseDatabase mFirebaseInstance;
owner owner;
customAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.prospectowner_listview);
list = findViewById(R.id.list);
LinearLayoutManager manager = new LinearLayoutManager(this);
list.setLayoutManager(manager);
list.setHasFixedSize(true);
manager.setOrientation(LinearLayoutManager.VERTICAL);
adapter = new customAdapter(prospectowner_listview.this,ownerlist);
list.setAdapter(adapter);
mFirebaseInstance = FirebaseDatabase.getInstance();
mFirebaseDatabase = mFirebaseInstance.getReference("owners");
mFirebaseDatabase.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot data: dataSnapshot.getChildren()){
owner o = data.getValue(owner.class);
ownerlist.add(o);
}
adapter.addData(ownerlist);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) { }
});
}
}
躍然一笑
TA貢獻1826條經驗 獲得超6個贊
在適配器中創建新功能：
public void addData(List<Owner> owners){
this.ownerList = owners;
notifyOnDataSetChanged();
}
并在onDataChange通話中：
adapter.addData(owners);
阿晨1998
TA貢獻2037條經驗 獲得超6個贊
試試這個，
在您的活動課程中更改
list.setAdapter(adapter)
到
list.setAdapter(new customAdapter(prospectowner_listview.this, ownerlist));
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