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上找到類別名稱沒有設置者/字段我試圖從Firebase數據庫檢索數據並將其顯示在視圖中。當ArrayList中的數據被編碼時，代碼工作正常。但它顯示爲空的觀點時ArrayList中的數據充滿了從火力地堡database。這檢索到的數據是什麼，我得到的日誌：是W/ClassMapper：在類
W/ClassMapper: No setter/field for categoryName found on class
W/ClassMapper: No setter/field for categoryImageUrl found on class
and so on..
這裏MainActivity.java（ECartHomeActivity.java）：使用（用於獲取數據）
public class ECartHomeActivity extends AppCompatActivity {
public static final String DATABASE_PATH_UPLOADS = "ProductCategoryModel";
// firebase objects
DatabaseReference databaseMessages;
ArrayList<ProductCategoryModel> productCategoryList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_ecart);
productCategoryList = new ArrayList<ProductCategoryModel>();
databaseMessages = FirebaseDatabase.getInstance().getReference(DATABASE_PATH_UPLOADS);
databaseMessages.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
productCategoryList.clear();
for (DataSnapshot messageSnapshot : dataSnapshot.getChildren()){ // iterates through all the messages
ProductCategoryModel message = messageSnapshot.getValue(ProductCategoryModel.class);
ProductCategoryModel fire = new ProductCategoryModel();
String categoryName = message.getProductCategoryName();
String categoryDescription = message.getProductCategoryDescription();
String categoryDiscount = message.getProductCategoryDiscount();
String categoryImageUrl = message.getProductCategoryImageUrl();
fire.setProductCategoryName(categoryName);
fire.setProductCategoryDescription(categoryDescription);
fire.setProductCategoryDiscount(categoryDiscount);
fire.setProductCategoryImageUrl(categoryImageUrl);
productCategoryList.add(fire);
}
CenterRepository.getCenterRepository().setListOfCategory(productCategoryList);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
}); }
如果「productCategoryList」ArrayList是硬編碼的，它將在視圖中顯示數據。 但是，如果此ArrayList填充了從數據庫檢索的數據，則不會顯示任何數據。
ProductCategoryModel.java
public class ProductCategoryModel {
public ProductCategoryModel(){
}
private String categoryName;
private String categoryDescription;
private String categoryDiscount;
private String categoryImageUrl;
/**
* @param productCategoryName
* @param productCategoryDescription
* @param productCategoryDiscount
* @param productCategoryUrl
*/
public ProductCategoryModel(String productCategoryName, String productCategoryDescription,
String productCategoryDiscount, String productCategoryUrl) {
super();
this.categoryName = productCategoryName;
this.categoryDescription = productCategoryDescription;
this.categoryDiscount = productCategoryDiscount;
this.categoryImageUrl = productCategoryUrl;
}
/**
* @return the idproductcategory
*/
public String getProductCategoryName() {
return categoryName;
}
/**
* @param categoryName
* the idproductcategory to set
*/
public void setProductCategoryName(String categoryName) {
this.categoryName = categoryName;
}
/**
* @return the productDescription
*/
public String getProductCategoryDescription() {
return categoryDescription;
}
/**
* @param categoryDescription
* the productDescription to set
*/
public void setProductCategoryDescription(String categoryDescription) {
this.categoryDescription = categoryDescription;
}
/**
* @return the productDiscount
*/
public String getProductCategoryDiscount() {
return categoryDiscount;
}
/**
* @param categoryDiscount
* the productDiscount to set
*/
public void setProductCategoryDiscount(String categoryDiscount) {
this.categoryDiscount = categoryDiscount;
}
/**
* @return the productUrl
*/
public String getProductCategoryImageUrl() {
return categoryImageUrl;
}
/**
* @param categoryImageUrl
* the productUrl to set
*/
public void setProductCategoryImageUrl(String categoryImageUrl) {
this.categoryImageUrl = categoryImageUrl;
} }
這是JSON代碼：
{
"ProductCategoryModel" : {
"1" : {
"categoryName" : "anonymous",
"categoryDescription" : "Heyyyy",
"categoryDiscount" : "anonymous",
"categoryImageUrl" : "anonymous"
},
"2" : {
"categoryName" : "anonymous",
"categoryDescription" : "Heyyyy",
"categoryDiscount" : "anonymous",
"categoryImageUrl" : "anonymous"
},
"3" : {
"categoryName" : "anonymous",
"categoryDescription" : "Heyyyy",
"categoryDiscount" : "anonymous",
"categoryImageUrl" : "anonymous"
} } }