Question

我正在创建一个领域另一个领域对象的领域对象，但是当我运行项目时，我得到一个带有父对象上的领域代理错误的空指针。我检查了两个对象的所有getter和setter，他们正在使用android studio生成的。任何人都可以建议为什么会出现这个错误。

父对象

public class FavouriteObject extends RealmObject {

    private String ID;
    private String type;
    private CategoryObject categoryObject;

    public FavouriteObject(){}

    public void setID(String ID){
        this.ID = ID;
    }

    public String getID(){
        return ID;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getType(){
        return type;
    }

    public void setCategoryObject(CategoryObject categoryObject){
        this.categoryObject = categoryObject;
    }

    public CategoryObject getCategoryObject(){
        return categoryObject;
    }

}

子对象

public class CategoryObject extends RealmObject {

    private String dateAdded;
    private String description;
    private String detailImage;
    private String featured;
    private String image;
    private String langID;
    private String navigateUrl;
    private String specialFeature;
    private String supplierName;
    private String weekAdded;
    private String title;

    private String id;
    private boolean newProduct;

    public void setNewProduct(boolean newProduct){
        this.newProduct = newProduct;
    }

    public boolean isNewProduct() {
        return newProduct;
    }

    public void setDateAdded(String dateAdded){
        this.dateAdded = dateAdded;
    }

    public String getDateAdded(){
        return dateAdded;
    }

    public void setDescription(String description){
        this.description = description;
    }

    public String getDescription(){
        return description;
    }

    public void setDetailImage(String detailImage){
        this.detailImage = detailImage;
    }

    public String getDetailImage(){
        return detailImage;
    }

    public void setFeatured(String featured){
        this.featured = featured;
    }

    public String getFeatured(){
        return featured;
    }

    public void setImage(String image){
        this.image = image;
    }

    public String getImage(){
        return image;
    }

    public void setLangID(String langID) {
        this.langID = langID;
    }

    public String getLangID(){
        return langID;
    }

    public void setNavigateUrl(String navigateUrl){
        this.navigateUrl = navigateUrl;
    }

    public String getNavigateUrl(){
        return navigateUrl;
    }

    public void setSpecialFeature(String specialFeature) {
        this.specialFeature = specialFeature;
    }

    public String getSpecialFeature(){
        return specialFeature;
    }

    public void setSupplierName(String supplierName) {
        this.supplierName = supplierName;
    }

    public String getSupplierName(){
        return supplierName;
    }

    public void setWeekAdded(String weekAdded) {
        this.weekAdded = weekAdded;
    }

    public String getWeekAdded(){
        return weekAdded;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getTitle(){
        return title;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getId(){
        return id;
    }
}

添加对象

realm.beginTransaction();
FavouritesObject favourite = realm.createObject(FavouritesObject.class);
favourite.setID(po.getID());
favourite.setType("microsite");
favourite.setCategoryObject(productsObject.get(position));

错误讯息

java.lang.NullPointerException
        at io.realm.FavouritesObjectRealmProxy.setCategoryObject(FavouritesObjectRealmProxy.java:64)
        at com.test.project.Adapters.CategoryAdapter$1.onClick(CategoryAdapter.java:101)
        at android.view.View.performClick(View.java:4438)
        at android.view.View$PerformClick.run(View.java:18422)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5001)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)

我还尝试创建一个只有一个变量的测试对象，但是我仍然有同样的问题。任何帮助都会很棒！

Answer 1

行favourite.setCategoryObject(productsObject.get(position));似乎是个问题。

您从productsObject.get(position)获得的价值是来自Realm（即它是由RealmResult<ProductsObject>还是realm.createObject(ProductsObject.class)或类似产品创建的。

如果您的ProductsObject从RealmObject继承的io.realm.internal.Row row和io.realm.Realm realm属性不为null，您就会知道该对象是由Realm创建的。

我建议更改此部分：

favourite.setType("microsite");
favourite.setCategoryObject(productsObject.get(position));

到

favourite.setType("microsite");
ProductsObject po = productsObject.get(position);
favourite.setCategoryObject(po);

然后在ProductsObject po = productsObject.get(position);行设置一个断点，以查看row上的realm或RealmObject属性（继承自po） object为null。如果它们中的任何一个或两个都为null，那么您需要更新该函数以确保您的productsObject.get(position)函数返回由Realm创建的值。

Realm对象上的RealmProxy错误

1 个答案: