使用单击 Spinner Item 刷新 ArrayList 以将新数据显示到 RecyclerView 中

Question

单击 Spinner 项将新数据添加到 RecyclerView 中而不删除旧数据。

就像，我在 Spinner 中有 two 个项目：Appliances 和 Accessories。

默认情况下，我在 RecyclerView 中显示 Appliances 数据，但每当我在 Accessories 上显示 tap ] - 它在 RecyclerView 中显示 Accessories data，但是 below Appliances data，而我期望只有 Accessories数据进入 RecyclerView

MainActivity.java:

public class MainActivity extends AppCompatActivity {

    .....

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu_screen);
        .........

        stringList = new ArrayList<String>();
        stringList.add("Appliances");
        stringList.add("Accessories");

        ArrayAdapter<String> stringArrayAdapter = new ArrayAdapter<String>(MainActivity.this,
                android.R.layout.simple_dropdown_item_1line,
                stringList);

        spinnerMenu.setAdapter(stringArrayAdapter);

        ......

        initializeAdapter();

        .....

        spinnerMenu.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

                switch (position) {
                    case 0:                            

                        presenter.loadAppliances();

                        break;

                    case 1:

                        presenter.loadAccessories();

                        break;
                }

            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });

        .......
    }

    public void initializeAdapter() {

        categoryAdapter = new CategoryAdapter(this, new ArrayList<Category>());
        mRecyclerView.setAdapter(categoryAdapter);
    }

    public void addMenu(List<Category> posts) {
        categoryAdapter.addAllData(posts);
        categoryAdapter.notifyDataSetChanged();
    }

}

CategoryAdapter.java:

    @Override
    public int getItemCount() {
        return posts.size();
    }

    public void setPosts(List<Categories> posts) {
        this.posts = posts;
    }

    public void clearData() {
        posts.clear();
    }

    public void addAllData(List<Categories> posts) {
        this.posts.addAll(posts);
    }

}

Answer 1

您需要在选择项目时重置适配器。所以试试这个：

 public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
       initializeAdapter();
       //after this the switch case

我还建议您有一种了解微调菜单位置的方法。先menupresenter.loadAppliances();后有int positionSelected = 0;

然后在开关盒中，

switch position
   case: 0
     if(positionSelected != 0) {
         initializeAdapter();
         menupresenter.loadAppliances();
         positionSelected = 0;
     }...

   case: 1
     if(positionSelected != 1) {
         initializeAdapter();
         menupresenter.loadAccessories();
         positionSelected = 1;
     }...

这将确保您不会不必要地重置 recyclerView 适配器。就像如果正在显示应用程序数据并且用户在下拉列表中再次选择应用程序

Answer 2

首先清除旧的 ArrayList，然后将数据添加到 Arraylist。

 public void addMenu(List<Category> posts) {
    categoryAdapter.addAllData(posts);
    categoryAdapter.notifyDataSetChanged();
}

public void addAllData(List<Categories> posts) {
    this.posts.clear();
    this.posts.addAll(posts);
}

使用单击 Spinner Item 刷新 ArrayList 以将新数据显示到 RecyclerView 中

Refresh ArrayList to show new Data into RecyclerView using Click on Spinner Item

java

android

arraylist

spinner

android-recyclerview