java-未填充RecyclerView(getItemCount()返回零)
作者:互联网
我查看了关于此的其他问题,并逐字地匹配了代码,但是我一定错过了一些东西,因为没有任何效果. getItemCount()返回零,但是我调试了数据列表,似乎可以正确添加所有数据,因此与适配器的通信出现了问题.
请告诉我这里出了什么问题!
下面是我的MainActivity.java代码:
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import com.parse.FindCallback;
import com.parse.ParseException;
import com.parse.ParseObject;
import com.parse.ParseQuery;
import com.parse.ParseUser;
import java.util.ArrayList;
import java.util.List;
public class Profile_Page extends ActionBarActivity {
UserLocalStore userLocalStore;
private RecyclerView recyclerView;
private DataAdapter adapter;
private Context context;
final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
public List<Information> data = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile__page);
ParseUser currentUser = ParseUser.getCurrentUser();
String struser = currentUser.getUsername();
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
Button logoutBtn = (Button) findViewById(R.id.logOutBtn);
adapter = new DataAdapter(getApplicationContext(), getData());
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
public List<Information> getData()
{
ParseQuery <ParseObject> query = ParseQuery.getQuery("ParseClassName");
query.whereEqualTo("author", ParseUser.getCurrentUser());
query.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(List<ParseObject> list, ParseException e) {
if (e == null) {
for (ParseObject getData : list) {
Information current = new Information();
current.thing= getData.getString("Thing");
data.add(current);
adapter.notifyDataSetChanged();
//for some reason, data isn't getting transferred to adapter
}
} else {
//something went wrong
}
}
});
return data;
}
public void logOut(View view)
{
// Logout current user
ParseUser.logOut();
finish();
}
}
DataAdapter的代码:
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Chronometer;
import android.widget.EditText;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class DataAdapter extends RecyclerView.Adapter<DataAdapter.MyViewHolder>
{
private LayoutInflater inflater;
List<Information> data = Collections.emptyList();
public DataAdapter(Context context, List<Information> data)
{
inflater = LayoutInflater.from(context);
this.data= data;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
View view = inflater.inflate(R.layout.recycler_view_layout, parent, false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position)
{
Information current = data.get(position);
holder.tv.setText(current.thing);
}
@Override
public int getItemCount()
{ Log.d("datasize", String.valueOf(data.size()));
return data.size();
}
class MyViewHolder extends RecyclerView.ViewHolder
{ TextView tv;
public MyViewHolder(View itemView) {
super(itemView);
tv= (TextView) itemView.findViewById(R.id.thingID);
}
}
}
Information.java
public class Information
{
public String thing;
}
Recycler_view_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Dummy Text"
android:id="@+id/thingID"/>
</LinearLayout>
添加了RecyclerView的活动:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.example.android.blah.Profile_Page"
>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
android:id="@+id/button3"
android:layout_alignParentTop="true"
android:layout_alignRight="@+id/recyclerView"
android:layout_alignEnd="@+id/recyclerView" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Log out"
android:id="@+id/logOutBtn"
android:layout_below="@+id/button3"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:onClick="logOut"
android:layout_marginTop="85dp" />
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height = "wrap_content"
android:id="@+id/recyclerView"
android:layout_alignTop="@id/logOutBtn" />
</RelativeLayout>
解决方法:
也许如果您在完成的方法中设置适配器,它将起作用.将底部插入循环.
adapter = new DataAdapter(getApplicationContext(), data);
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
标签:recycler-adapter,android-recyclerview,java,android 来源: https://codeday.me/bug/20191028/1949409.html