Question

您好我刚刚设置了这个RecyclerView并且无法找到错误的内容。提前致谢。我确定RecyclerView正在显示，虽然它们在主活动屏幕上是一个微弱的阴影，我可以拉下来拉起来。我认为问题可能围绕我的线活动的这一部分：

    getSupportActionBar().setTitle(null);
    recyclerView = (RecyclerView) findViewById(R.id.line_list);
    adapter=new MyAdapter(getApplicationContext(),getData());
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));

活动代码;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

import java.util.ArrayList;
import java.util.List;


public class Lines extends AppCompatActivity {

private RecyclerView recyclerView;
private MyAdapter adapter;


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

    Toolbar myToolbar = (Toolbar) findViewById(R.id.toolbar_top);
    setSupportActionBar(myToolbar);
    getSupportActionBar().setTitle(null);
    recyclerView = (RecyclerView) findViewById(R.id.line_list);
    adapter=new MyAdapter(getApplicationContext(),getData());
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new     LinearLayoutManager(getApplicationContext()));

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main_item, menu);
    return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int i = item.getItemId();
    switch (i) {
        case R.id.action_search:
            Intent s = new Intent(this, SearchActivity.class);
            startActivity(s);
            return true;

        case R.id.action_add:
            Intent a = new Intent(this, AddLine.class);
            startActivity(a);
            return true;


        case R.id.action_wheel:
            Intent w = new Intent(this, Settings.class);
            startActivity(w);
            return true;

    }
    return super.onOptionsItemSelected(item);
}

public static  List<Information> getData(){

    List<Information> data=new ArrayList<>();

    int[] icons={R.drawable.ic_place_black_24dp,R.drawable.ic_place_black_24dp2,
            R.drawable.ic_place_black_24dp3};

    String[] titles={"Homework","Birthday","Index"};

    for(int i=0;i<titles.length && i<icons.length;i++){

        Information current=new Information();

        current.iconId=icons[i];

        current.title=titles[i];

        data.add(current);

    }
    return data;
}

}

.xml代码：

<LinearLayout 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:orientation="vertical"
tools:context=".Lines">

<android.support.v7.widget.Toolbar
    android:id="@+id/toolbar_top"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#000000"
    android:minHeight="?attr/actionBarSize">

    <TextView
        android:id="@+id/toolbar_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="LINES"
        android:textColor="#ffffff"
        android:textSize="25sp" />
</android.support.v7.widget.Toolbar>

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

</android.support.v7.widget.RecyclerView>

</LinearLayout>

行元素定义活动代码：

package com.example.patri.index01;

public class Information {

int iconId;

String title;

}

适配器活动代码：

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Collections;
import java.util.List;

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private LayoutInflater inflater;
List<Information> data= Collections.emptyList();
public MyAdapter(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.custom_row, parent,false);
    MyViewHolder holder=new MyViewHolder(view);
    return holder;
}

@Override
public void onBindViewHolder(MyViewHolder holder, int position) {

    Information current=data.get(position);

    holder.title.setText(current.title);
    holder.icon.setImageResource(current.iconId);


}

@Override
public int getItemCount() {
    return 0;
}

class MyViewHolder extends RecyclerView.ViewHolder{
    TextView title;

    ImageView icon;

    public MyViewHolder(View itemView) {

        super(itemView);

        title= (TextView)itemView.findViewById(R.id.listText);

        icon= (ImageView) itemView.findViewById(R.id.listIcon);

    }
}
}

行.xml代码：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent">

<ImageView
    android:id="@+id/listIcon"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_place_black_24dp"
    android:padding="8dp"/>
<TextView
    android:id="@+id/listText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Dummy text"
    android:padding="8dp"
    android:textColor="#000000"/>
</LinearLayout>

Answer 1

您的项目数为0。

@Override
public int getItemCount() {
    return 0;
}

您应该返回data.size()

你应该修复你的row.xml，以便它的高度只有它所需要的大小：

<LinearLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="wrap_content">

Answer 2

将row.xml中的linearlayout的layout_height设置为wrap_content而不是match_parent。这就是为什么它会填满整个屏幕。

RecyclerView没有出现

2 个答案: