RecyclerView 将数据库条目显示为空字符串
RecyclerView showing database entries as null strings
我正在开发一个 Android 应用程序，它使用 PHP API 和改造。我的 SQL 数据库有一个 "orders" table，它是 "users" 和 "foods" table 之间连接的结果。我的代码成功地在不同片段的回收视图中显示 "users" 和 "foods"，但是相同的方法无法显示 "orders" 并且我得到一个空的回收视图（具有正确的行数和订单项 table) 但字符串为空且整数为 0。代码运行时没有错误。我还在 POSTMAN 中测试了 PHP 请求并且响应是正确的，所以 PHP 代码运行良好。你能告诉我这段代码有什么问题吗？问题可能与在连接查询中使用其他 table 的列有关吗？请朋友们帮帮我。
我在 Logcat 中找到了这个：2019-08-08 00:43:52.967 21951-21951/com.nikappzaar.app.foodtakeout E/RecyclerView：未连接适配器；跳过布局
public function getAllOrders(){
$stmt = $this->con->prepare(
"SELECT o.oid, o.uid, o.fid, o.quantity, o.otime
, f.fname, f.unitprice
, u.phone, u.uname, u.uaddress
FROM orders o
INNER JOIN foods f
on o.fid = f.fid
INNER JOIN users u
on o.uid = u.uid ;");
$stmt->execute();
$stmt->bind_result($oid, $uid, $fid, $quantity, $otime, $fname, $unitprice, $phone, $uname, $uaddress);
$orders = array();
while($stmt->fetch()){
$order = array();
$order['o.oid'] = $oid;
$order['o.uid'] = $uid;
$order['o.fid'] = $fid;
$order['o.quantity']=$quantity;
$order['o.otime'] = $otime;
$order['f.fname'] = $fname;
$order['f.unitprice'] = $unitprice;
$order['u.phone']=$phone;
$order['u.uname'] = $uname;
$order['u.uaddress'] = $uaddress;
array_push($orders, $order);
}
return $orders;
}
OperatorHomeFargment.java
public class OperatorHomeFragment extends Fragment {
private RecyclerView recyclerView;
private OrdersAdapter adapter;
private List<Order> orderList;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_orders, container, false);
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
recyclerView = view.findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
Call<OrdersResponse> call = RetrofitClient.getInstance().getApi().getOrders();
call.enqueue(new Callback<OrdersResponse>() {
@Override
public void onResponse(Call<OrdersResponse> call, Response<OrdersResponse> response) {
orderList = response.body().getOrders();
adapter = new OrdersAdapter(getActivity(), orderList);
recyclerView.setAdapter(adapter);
}
@Override
public void onFailure(Call<OrdersResponse> call, Throwable t) {
}
});
}
}
OrdersAdapter.java
public class OrdersAdapter extends RecyclerView.Adapter<OrdersAdapter.OrdersViewHolder> {
private Context mCtx;
private List<Order> orderList;
public OrdersAdapter(Context mCtx, List<Order> orderList) {
this.mCtx = mCtx;
this.orderList = orderList;
}
@NonNull
@Override
public OrdersViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(mCtx).inflate(R.layout.recyclerview_orders, parent, false);
return new OrdersViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull OrdersViewHolder holder, int position) {
Order order = orderList.get(position);
holder.textViewOId.setText(String.format("%d", order.getOId()));
holder.textViewOTime.setText(order.getOTime());
holder.textViewFName.setText(order.getFName());
holder.textViewQuantity.setText(String.format("%d", order.getQuantity()));
holder.textViewUnitPrice.setText(String.format("%d", order.getUnitPrice()));
holder.textViewPhone.setText(order.getPhone());
holder.textViewUName.setText(order.getUName());
holder.textViewUAddress.setText(order.getUAddress());
}
@Override
public int getItemCount() {
return orderList.size();
}
class OrdersViewHolder extends RecyclerView.ViewHolder {
TextView textViewOId, textViewOTime, textViewFName, textViewQuantity, textViewUnitPrice,
textViewPhone, textViewUName, textViewUAddress;
public OrdersViewHolder(View itemView) {
super(itemView);
textViewOId = itemView.findViewById(R.id.textViewOId);
textViewOTime = itemView.findViewById(R.id.textViewOTime);
textViewFName = itemView.findViewById(R.id.textViewFName);
textViewQuantity = itemView.findViewById(R.id.textViewQuantity);
textViewUnitPrice = itemView.findViewById(R.id.textViewUnitPrice);
textViewPhone = itemView.findViewById(R.id.textViewPhone);
textViewUName = itemView.findViewById(R.id.textViewFName);
textViewUAddress = itemView.findViewById(R.id.textViewUAddress);
}
}
}
Order.java
public class Order {
private int oid, uid, fid, quantity, unitprice;
private String otime, fname, phone, uname, uaddress;
public Order(int oid, int uid, int fid, int quantity, String otime,
String fname, int unitprice, String phone, String uname, String uaddress) {
this.oid = oid;
this.uid = uid;
this.fid = fid;
this.quantity = quantity;
this.otime = otime;
this.fname = fname;
this.unitprice = unitprice;
this.phone = phone;
this.uname = uname;
this.uaddress = uaddress;
}
public int getOId() {
return oid;
}
public int getUId() {
return uid;
}
public int getFId() {
return fid;
}
public int getQuantity() {
return quantity;
}
public String getOTime() {
return otime;
}
public String getFName() {
return fname;
}
public int getUnitPrice() {
return unitprice;
}
public String getPhone() {
return phone;
}
public String getUName() {
return uname;
}
public String getUAddress() {
return uaddress;
}
}
recyclerview_orders.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="3dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="4dp">
<TextView
android:id="@+id/textViewOId"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewOTime"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewFName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Headline" />
<TextView
android:id="@+id/textViewQuantity"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewUnitPrice"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewPhone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewUName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Headline" />
<TextView
android:id="@+id/textViewUAddress"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
</LinearLayout>
</android.support.v7.widget.CardView>
</RelativeLayout>
fragment_orders.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
如果您在 Fragment 中调用 OperatorHomeFragment 使用 getChildFragmentManager() 而不是 FragmentManager
中的 getSupportFragmentManager()
我从评论中了解到，您在将响应 json 解析为模型 class 时遇到问题。您能否尝试在 Order class 和 @SerializedName("json_key_name") 注释中将默认构造函数放置到与 json 键具有不同名称的属性顶部。
我正在开发一个 Android 应用程序，它使用 PHP API 和改造。我的 SQL 数据库有一个 "orders" table，它是 "users" 和 "foods" table 之间连接的结果。我的代码成功地在不同片段的回收视图中显示 "users" 和 "foods"，但是相同的方法无法显示 "orders" 并且我得到一个空的回收视图（具有正确的行数和订单项 table) 但字符串为空且整数为 0。代码运行时没有错误。我还在 POSTMAN 中测试了 PHP 请求并且响应是正确的，所以 PHP 代码运行良好。你能告诉我这段代码有什么问题吗？问题可能与在连接查询中使用其他 table 的列有关吗？请朋友们帮帮我。
我在 Logcat 中找到了这个：2019-08-08 00:43:52.967 21951-21951/com.nikappzaar.app.foodtakeout E/RecyclerView：未连接适配器；跳过布局
public function getAllOrders(){
$stmt = $this->con->prepare(
"SELECT o.oid, o.uid, o.fid, o.quantity, o.otime
, f.fname, f.unitprice
, u.phone, u.uname, u.uaddress
FROM orders o
INNER JOIN foods f
on o.fid = f.fid
INNER JOIN users u
on o.uid = u.uid ;");
$stmt->execute();
$stmt->bind_result($oid, $uid, $fid, $quantity, $otime, $fname, $unitprice, $phone, $uname, $uaddress);
$orders = array();
while($stmt->fetch()){
$order = array();
$order['o.oid'] = $oid;
$order['o.uid'] = $uid;
$order['o.fid'] = $fid;
$order['o.quantity']=$quantity;
$order['o.otime'] = $otime;
$order['f.fname'] = $fname;
$order['f.unitprice'] = $unitprice;
$order['u.phone']=$phone;
$order['u.uname'] = $uname;
$order['u.uaddress'] = $uaddress;
array_push($orders, $order);
}
return $orders;
}
OperatorHomeFargment.java
public class OperatorHomeFragment extends Fragment {
private RecyclerView recyclerView;
private OrdersAdapter adapter;
private List<Order> orderList;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_orders, container, false);
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
recyclerView = view.findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
Call<OrdersResponse> call = RetrofitClient.getInstance().getApi().getOrders();
call.enqueue(new Callback<OrdersResponse>() {
@Override
public void onResponse(Call<OrdersResponse> call, Response<OrdersResponse> response) {
orderList = response.body().getOrders();
adapter = new OrdersAdapter(getActivity(), orderList);
recyclerView.setAdapter(adapter);
}
@Override
public void onFailure(Call<OrdersResponse> call, Throwable t) {
}
});
}
}
OrdersAdapter.java
public class OrdersAdapter extends RecyclerView.Adapter<OrdersAdapter.OrdersViewHolder> {
private Context mCtx;
private List<Order> orderList;
public OrdersAdapter(Context mCtx, List<Order> orderList) {
this.mCtx = mCtx;
this.orderList = orderList;
}
@NonNull
@Override
public OrdersViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(mCtx).inflate(R.layout.recyclerview_orders, parent, false);
return new OrdersViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull OrdersViewHolder holder, int position) {
Order order = orderList.get(position);
holder.textViewOId.setText(String.format("%d", order.getOId()));
holder.textViewOTime.setText(order.getOTime());
holder.textViewFName.setText(order.getFName());
holder.textViewQuantity.setText(String.format("%d", order.getQuantity()));
holder.textViewUnitPrice.setText(String.format("%d", order.getUnitPrice()));
holder.textViewPhone.setText(order.getPhone());
holder.textViewUName.setText(order.getUName());
holder.textViewUAddress.setText(order.getUAddress());
}
@Override
public int getItemCount() {
return orderList.size();
}
class OrdersViewHolder extends RecyclerView.ViewHolder {
TextView textViewOId, textViewOTime, textViewFName, textViewQuantity, textViewUnitPrice,
textViewPhone, textViewUName, textViewUAddress;
public OrdersViewHolder(View itemView) {
super(itemView);
textViewOId = itemView.findViewById(R.id.textViewOId);
textViewOTime = itemView.findViewById(R.id.textViewOTime);
textViewFName = itemView.findViewById(R.id.textViewFName);
textViewQuantity = itemView.findViewById(R.id.textViewQuantity);
textViewUnitPrice = itemView.findViewById(R.id.textViewUnitPrice);
textViewPhone = itemView.findViewById(R.id.textViewPhone);
textViewUName = itemView.findViewById(R.id.textViewFName);
textViewUAddress = itemView.findViewById(R.id.textViewUAddress);
}
}
}
Order.java
public class Order {
private int oid, uid, fid, quantity, unitprice;
private String otime, fname, phone, uname, uaddress;
public Order(int oid, int uid, int fid, int quantity, String otime,
String fname, int unitprice, String phone, String uname, String uaddress) {
this.oid = oid;
this.uid = uid;
this.fid = fid;
this.quantity = quantity;
this.otime = otime;
this.fname = fname;
this.unitprice = unitprice;
this.phone = phone;
this.uname = uname;
this.uaddress = uaddress;
}
public int getOId() {
return oid;
}
public int getUId() {
return uid;
}
public int getFId() {
return fid;
}
public int getQuantity() {
return quantity;
}
public String getOTime() {
return otime;
}
public String getFName() {
return fname;
}
public int getUnitPrice() {
return unitprice;
}
public String getPhone() {
return phone;
}
public String getUName() {
return uname;
}
public String getUAddress() {
return uaddress;
}
}
recyclerview_orders.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="3dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="4dp">
<TextView
android:id="@+id/textViewOId"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewOTime"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewFName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Headline" />
<TextView
android:id="@+id/textViewQuantity"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewUnitPrice"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewPhone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:id="@+id/textViewUName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Headline" />
<TextView
android:id="@+id/textViewUAddress"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text=""
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
</LinearLayout>
</android.support.v7.widget.CardView>
</RelativeLayout>
fragment_orders.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
如果您在 Fragment 中调用 OperatorHomeFragment 使用 getChildFragmentManager() 而不是 FragmentManager
getSupportFragmentManager()
我从评论中了解到，您在将响应 json 解析为模型 class 时遇到问题。您能否尝试在 Order class 和 @SerializedName("json_key_name") 注释中将默认构造函数放置到与 json 键具有不同名称的属性顶部。