Question

当一个表中没有可用数据时，我想在RecyclerView中显示（“空”）。现在，当没有可用数据时，我的当前视图将如下图所示

https://scontent.fkul14-1.fna.fbcdn.net/v/t1.0-9/60093724_10216107031681720_3339793009188274176_n.jpg?_nc_cat=106&_nc_eui2=AeE2gJxeFI5ifgJkgcAXJZbsvtp3BiL6w5TtndQ4PO5emnLkh93oOJ_37m6KjbsZJ0QZsU8T6a9q_0Bg38t80eJcwkSiPbye1y9Ad6Ssx2TUrA&_nc_ht=scontent.fkul14-1.fna&oh=2a7d7090bfa7945893bcb973fc26005b&oe=5D5CE2D8

“ Tan Kian Guan Guan”名称保持可用的原因可能是由于用户登录后，它将在“ users”表中获取有关该用户的所有信息。

下面是我的代码。

MyHistoryList.java

    public class MyHistoryList extends AppCompatActivity {

List<User> userList;

RecyclerView recyclerView;
private String approveID;

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

    if(getIntent() != null) {
        approveID = getIntent().getStringExtra("approveType");
    }
    else{}

    final ActionBar abar = getSupportActionBar();
    View viewActionBar = getLayoutInflater().inflate(R.layout.activity_my_history_list, null);
    ActionBar.LayoutParams params = new ActionBar.LayoutParams(//Center the textview in the ActionBar !
            ActionBar.LayoutParams.WRAP_CONTENT,
            ActionBar.LayoutParams.MATCH_PARENT,
            Gravity.CENTER);
    TextView tvTitle = viewActionBar.findViewById(R.id.title);
    tvTitle.setText("MY HISTORY LIST");
    abar.setCustomView(viewActionBar, params);
    abar.setDisplayShowCustomEnabled(true);
    abar.setDisplayShowTitleEnabled(false);
    // abar.setDisplayHomeAsUpEnabled(true);
    abar.setHomeButtonEnabled(true);

    recyclerView = findViewById(R.id.recylcerView);
    recyclerView.addItemDecoration(new DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL));
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    User user = SharedPrefManager.getInstance(this).getUser();

    userList = new ArrayList<>();

    loadHistory(user.getBadgeid());
}

private void loadHistory(String badgeid) {
    StringRequest stringRequest = new StringRequest(Request.Method.GET,
            URLs.URL_LIST+"?badgeid="+ badgeid,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    try {
                        JSONArray array = new JSONArray(response);
                        for (int i = 0; i < array.length(); i++) {

                            //getting product object from json array
                            JSONObject userJson = array.getJSONObject(i);

                                userList.add(new User(
                                        userJson.getInt("id"),
                                        userJson.getString("name"),
                                        userJson.getString("badgeid"),
                                        userJson.getString("position"),
                                        userJson.getString("department"),
                                        userJson.getString("factory"),
                                        userJson.getString("reviewer"),
                                        userJson.getString("title"),
                                        userJson.getString("year"),
                                        userJson.getString("month"),
                                        userJson.getString("suggestionwill"),
                                        userJson.getString("present"),
                                        userJson.getString("details"),
                                        userJson.getString("benefit"),
                                        userJson.getString("photo"),
                                        userJson.getString("status"),
                                        userJson.getString("comment")
                                ));
                        }
                        UserAdapter adapter = new UserAdapter(MyHistoryList.this, userList);
                        recyclerView.setAdapter(adapter);

                        adapter.setClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                int post = recyclerView.indexOfChild(v);
                                User user = userList.get(post);
                                Intent myIntent = new Intent(MyHistoryList.this, MyHistory.class);
                                myIntent.putExtra("user", user);
                                myIntent.putExtra("approveType",approveID);
                                startActivity(myIntent);
                            }
                        });
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {

                }
            });

    //adding our stringrequest to queue
    Volley.newRequestQueue(this).add(stringRequest);
}

}

activity_my_history_list.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:id="@+id/haha"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MyHistoryList">
<TextView
    android:id="@+id/title"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:maxLines="1"
    android:clickable="false"
    android:focusable="false"
    android:longClickable="false"
    android:textStyle="bold"
    android:textSize="18sp"
    android:textColor="#FFFFFF" />

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recylcerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

有人可以帮忙吗？谢谢

Answer 1

尝试这样

     <android.support.v7.widget.RecyclerView
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scrollbars="vertical" />

<TextView
    android:id="@+id/empty_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:visibility="gone"
    android:text="@string/no_data_available" />

在您的班级文件中

 @Override
public void onResponse(String response) {
if(response==null){
recyclerView.setVisibility(View.Gone) 
emptyView.setVisibility(View.Visible)
}else{
    try {
    JSONArray array = new JSONArray(response);      
    //add this condition
    if(array.length() == 0){

Answer 2

您可以在解析数据时知道空数据，

尝试一下

编辑：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:id="@+id/haha"
   android:layout_height="match_parent"
   android:orientation="vertical"
   tools:context=".MyHistoryList">
<TextView
    android:id="@+id/title"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:maxLines="1"
    android:clickable="false"
    android:focusable="false"
    android:longClickable="false"
    android:textStyle="bold"
    android:textSize="18sp"
    android:textColor="#FFFFFF" />

<LinearLayout
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:orientation="vertical"
   >
<android.support.v7.widget.RecyclerView
    android:id="@+id/recylcerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

        <TextView
                android:visibility="gone"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/emptyView"
                android:text="List is Empty"
                android:textSize="@dimen/text_15sp"/>
     </LinearLayout>

在“活动”中声明textview ID：

 public class MyHistoryList extends AppCompatActivity {

 List<User> userList;
 TextView emptyView;

 RecyclerView recyclerView;
 private String approveID;

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

 //Declare TextView
 emptyView = findiViewById(R.id.emptyView);

  if(getIntent() != null) {
    approveID = getIntent().getStringExtra("approveType");
  }


private void loadHistory(String badgeid) {
StringRequest stringRequest = new StringRequest(Request.Method.GET,
        URLs.URL_LIST+"?badgeid="+ badgeid,
        new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                try {
                    JSONArray array = new JSONArray(response);

                    //add this condition

                    if(array.length() == 0){
                      //display empty with your code.
                      emptyView.setVisibility(View.VISIBLE);
                      recylcerView.setVisibility(View.GONE);
                    }else{
                      emptyView.setVisibility(View.GONE);
                      recylcerView.setVisibility(View.VISIBLE);
                    for (int i = 0; i < array.length(); i++) {

                        //getting product object from json array
                        JSONObject userJson = array.getJSONObject(i);

                            userList.add(new User(
                                    userJson.getInt("id"),
                                    userJson.getString("name"),
                                    userJson.getString("badgeid"),
                                    userJson.getString("position"),
                                    userJson.getString("department"),
                                    userJson.getString("factory"),
                                    userJson.getString("reviewer"),
                                    userJson.getString("title"),
                                    userJson.getString("year"),
                                    userJson.getString("month"),
                                    userJson.getString("suggestionwill"),
                                    userJson.getString("present"),
                                    userJson.getString("details"),
                                    userJson.getString("benefit"),
                                    userJson.getString("photo"),
                                    userJson.getString("status"),
                                    userJson.getString("comment")
                            ));
                    }
                    }
                    UserAdapter adapter = new UserAdapter(MyHistoryList.this, userList);
                    recyclerView.setAdapter(adapter);

                    adapter.setClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            int post = recyclerView.indexOfChild(v);
                            User user = userList.get(post);
                            Intent myIntent = new Intent(MyHistoryList.this, MyHistory.class);
                            myIntent.putExtra("user", user);
                            myIntent.putExtra("approveType",approveID);
                            startActivity(myIntent);
                        }
                    });
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        },
        new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {

            }
        });

//adding our stringrequest to queue
Volley.newRequestQueue(this).add(stringRequest);

}

这有效。尝试让我知道。编码愉快。

当基于表的数据库中没有数据时，RecyclerView显示（“空”）

2 个答案: