如何使全局对象的数据适应微调器

Question

我有我的 GlobalClass extends 应用程序 class。我想将全局对象数据绑定到微调器。这是我的 GlobalClass

public class GlobalClass extends Application {

private List<ProjectType> projectTypes;

public List<ProjectType> getProjectTypes() {
    return projectTypes;
}

public void setProjectTypes(List<ProjectType> projectTypes) {
    this.projectTypes = projectTypes;
} 
}

Pojo class

public class ProjectType implements Serializable {
private Integer projectTypeId;
private String typeName;
private Integer peckOrder;

//getter and setter here

然后我使用 volley 从服务器获得响应并使用 GSON 解析并将响应设置为 GlobalClass 这里是代码

JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.GET, getString(R.string.TEST_projectTypeURL), null, new Response.Listener<JSONArray>() {
        @Override
        public void onResponse(JSONArray response) {
            final GlobalClass globalVariable = (GlobalClass) getApplicationContext();
            Gson gson = new Gson();
            List<ProjectType> projectTypes = gson.fromJson(String.valueOf(response),List.class);
            globalVariable.setProjectTypes(projectTypes);
        }
    }

最后在另一个 activity class 中，我使用微调器绑定来自 GlobalClass 对象的数据

globalVariable = (GlobalClass) getApplicationContext();
    List<String> projectTypeList = new ArrayList<>();

    ArrayList<ProjectType> projectTypesCollection = new ArrayList<ProjectType>(globalVariable.getProjectTypes());

    for (ProjectType projectType: projectTypesCollection) {

        projectTypeList.add(projectType.getTypeName());
    }

    prjtTypeSpinner = (Spinner)findViewById(R.id.spn_prjt_type);
    ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_spinner_item,projectTypeList);
    dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    prjtTypeSpinner.setAdapter(dataAdapter);

在尝试上面的代码时出现错误 "com.google.gson.internal.LinkedTreeMap cannot be cast to the pojo.ProjectType class"

这里是对象 return 值，

[{projectTypeId=3.0, typeName=ALS, peckOrder=220.0}, {projectTypeId=2.0, typeName=ALB, peckOrder=210.0}, {projectTypeId=1.0, typeName=CL, peckOrder=200.0}, {projectTypeId=7.0, typeName=ACG, peckOrder=40.0}, {projectTypeId=6.0, typeName=ACS, peckOrder=30.0}, {projectTypeId=5.0, typeName=ACB, peckOrder=20.0}, {projectTypeId=4.0, typeName=CC, peckOrder=10.0}]

我想要微调器中的 typeName。提前致谢。

Answer 1

我认为您对这段代码有疑问

List<ProjectType> projectTypes = gson.fromJson(String.valueOf(response),List.class);

您需要更改为：

List<ProjectType> projectTypes = gson.fromJson(new Gson().toJson(response),new TypeToken<List<ProjectType>>() {
            }.getType());

Answer 2

我终于解决了这个问题，

Arrays.asList(gson.fromJson(response, ProjectType[].class))

当我尝试代码时，我的错误得到解决，这段代码运行良好

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