我是 Android 和一般编程新手。我正在尝试加载 RecyclerView 一些数据。 在 Debug模式下，直到应用程序崩溃时才显示错误。 这里使用的主要数据是一个名为 Lettura 的实体，它是房间数据库的一部分。
这里我调用并用一些数据填充 View :
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.vedi_letture_simple);
ArrayList<Lettura> letture = new ArrayList<>();
Date date = new Date(1989, 1, 1);
Lettura a = new Lettura("a", "b", "c", 14.5, date, 1);
letture.add(a);
RecyclerView recView = (RecyclerView) findViewById(R.id.lettura_recyclerview);
LetturaAdapter mlAdapter = new LetturaAdapter(this, letture); //made final
recView.setAdapter(mlAdapter);
// use a linear layout manager
LinearLayoutManager lll = new LinearLayoutManager(this);
recView.setLayoutManager(lll);
这里是适配器类LetturaAdapter.class
class LetturaAdapter extends RecyclerView.Adapter<LetturaAdapter.LetturaViewHolder> {
private ArrayList<Lettura> letture;
private LayoutInflater mInflater;
public LetturaAdapter(Context context, ArrayList<Lettura> lettura){
this.mInflater = LayoutInflater.from(context);
this.letture = lettura;
}
@Override
public LetturaViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
Context context = parent.getContext();
LayoutInflater mInflater = LayoutInflater.from(context);
View viewRiga = mInflater.inflate(R.layout.lettura_recyclerview_element, parent, false);
LetturaViewHolder rigaHolded = new LetturaViewHolder(viewRiga);
return rigaHolded;
}
@Override
public void onBindViewHolder(LetturaViewHolder rigaHolded, int position) {
Lettura current;
current = letture.get(position);
TextView barT = hholded.barcodeItemView;
barT.setText(current.getBarcode());
TextView desT = hholded.descriptionItemView;
desT.setText(current.getDescription());
TextView priceT = hholded.priceItemView;
priceT.setText(current.getPrice().toString());
TextView dateT = hholded.dateItemView;
dateT.setText(current.getDate().toString());
TextView quanT = hholded.quantityItemView;
quanT.setText(current.getQuantity());
}
@Override
public int getItemCount() {
if (letture != null)
return letture.size();
else return 0;
}
public class LetturaViewHolder extends RecyclerView.ViewHolder {
TextView barcodeItemView;
TextView descriptionItemView;
TextView priceItemView;
TextView dateItemView;
TextView quantityItemView;
public LetturaViewHolder(View itemView) {
super(itemView);
barcodeItemView = itemView.findViewById(R.id.barcodeTextView);
descriptionItemView = itemView.findViewById(R.id.descriptionTextView);
priceItemView = itemView.findViewById(R.id.priceTextView);
dateItemView = itemView.findViewById(R.id.dateTextView);
quantityItemView = itemView.findViewById(R.id.quantityTextView);
}
}
这里是 Lettura 类
@Entity(tableName = "Lettura", indices = {@Index(value="barcode", unique=true)})// indices speeds the search
public class Lettura {
@PrimaryKey(autoGenerate = true)
public int id;
@NonNull
public String codNeg;
@NonNull
public String barcode;
public String description;
@NonNull
public Double price;
public Date date;
public int quantity;
public Lettura(String codNeg, String barcode, String description, Double price, Date date, int quantity) {
this.codNeg = codNeg;
this.barcode = barcode;
this.description = description;
this.price = price;
this.date = date;
this.quantity = quantity;
}
public String getCodNeg() {return this.codNeg;}
public String getBarcode() {return this.barcode;}
public String getDescription() {return this.description;}
public Double getPrice() {return this.price;}
public Date getDate() {return this.date;}
public Integer getQuantity() {return this.quantity;}
}
这里是 RecyclerView 的 xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/colorScreenBackground">
<android.support.v7.widget.RecyclerView
android:id="@+id/lettura_recyclerview"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
最后是元素的 xml:
<?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"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/barcodeTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="1dp"
android:layout_marginLeft="1dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:text="barcode"
app:layout_constraintEnd_toEndOf="@+id/dateTextView"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@+id/dateTextView" />
<TextView
android:id="@+id/descriptionTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="1dp"
android:layout_marginLeft="1dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="1dp"
android:layout_marginRight="1dp"
android:layout_marginBottom="8dp"
android:text="description"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/barcodeTextView"
app:layout_constraintVertical_bias="0.0" />
<TextView
android:id="@+id/priceTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:text="price"
app:layout_constraintEnd_toStartOf="@+id/dateTextView"
app:layout_constraintTop_toTopOf="@+id/dateTextView" />
<TextView
android:id="@+id/dateTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="1dp"
android:layout_marginEnd="1dp"
android:layout_marginRight="1dp"
android:text="date"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/quantityTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginEnd="4dp"
android:layout_marginRight="4dp"
android:layout_marginBottom="8dp"
android:text="quantity"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@+id/priceTextView"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toEndOf="@+id/barcodeTextView"
app:layout_constraintTop_toTopOf="@+id/dateTextView"
app:layout_constraintVertical_bias="0.0" />
<View
android:id="@+id/divider"
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_weight="1"
android:background="#008AD4"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView3" />
</android.support.constraint.ConstraintLayout>
</LinearLayout>
最佳答案
我猜错误在这里:
TextView quanT = hholded.quantityItemView;
quanT.setText(current.getQuantity());
current.getQuantity() 返回一个 Integer 而不是 String。也许，你可以尝试:
TextView quanT = hholded.quantityItemView;
quanT.setText(current.getQuantity().toString());
关于java - RecyclerView崩溃，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/56808128/