Question

点击“添加”按钮后，它只显示第一项。但是当我触摸编辑文本字段时，剩余的项目会显示并消失。

以下是MainActivity：

package com.example.mysecondapp.myapplication;

import android.content.Context;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    RecyclerView recyclerView;
    EditText editText;
    Button add,ins;
    ArrayList<item> list;
    Adapter adpter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        ins= (Button) findViewById(R.id.button1);
        add= (Button) findViewById(R.id.button2);
        editText= (EditText) findViewById(R.id.editText2);
        recyclerView= (RecyclerView) findViewById(R.id.recycler);
        list=new ArrayList<item>();
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        adpter =new Adapter(new ArrayList<item>());
        recyclerView.setAdapter(adpter);


        ins.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String str=editText.getText().toString();
                InputMethodManager inputMethodManager= (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
                inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(),0);
                editText.setText(" ");
                Toast.makeText(getBaseContext(),"Added to list",Toast.LENGTH_SHORT).show();
                item i=new item(str);
                list.add(i);
            }
        });
        add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                adpter.adplist=list;
                Toast.makeText(getBaseContext(),"Adding to Recycler View",Toast.LENGTH_SHORT).show();
                adpter.notifyDataSetChanged();
            }
        });



       FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

这是适配器

package com.example.mysecondapp.myapplication;

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;

public class Adapter extends RecyclerView.Adapter<Adapter.MyHolder> {
    ArrayList<item> adplist;

    public ArrayList<item> getAdplist() {
        return adplist;
    }

    public void setAdplist(ArrayList<item> adplist) {
        this.adplist = adplist;
    }

    public Adapter(ArrayList<item>list) {
        adplist=new ArrayList<item>();

        adplist=list;
    }

    @Override
    public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View v= LayoutInflater.from(parent.getContext()).inflate(R.layout.item,parent,false);
        return new MyHolder(v);
    }

    @Override
    public void onBindViewHolder(MyHolder holder, int position) {
        item i=adplist.get(position);
        holder.tv.setText(i.getStr());

    }

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

    public class MyHolder extends  RecyclerView.ViewHolder{
        TextView tv;
        public MyHolder(View itemView) {
            super(itemView);
            tv=itemView.findViewById(R.id.item_text_view);
        }
    }
}

这是项目

package com.example.mysecondapp.myapplication;

public class item {
    String str;

    public item(String str) {
        this.str = str;
    }

    public String getStr() {
        return str;
    }

    public void setStr(String str) {
        this.str = str;
    }
}

这是活动xml：

 <?xml version="1.0" encoding="utf-8"?>
    <android.support.design.widget.CoordinatorLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        tools:context="com.example.mysecondapp.myapplication.MainActivity">

        <android.support.design.widget.AppBarLayout
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:theme="@style/AppTheme.AppBarOverlay">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay" />

        </android.support.design.widget.AppBarLayout>

        <include layout="@layout/content_main"/>

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="@dimen/fab_margin"
            app:srcCompat="@android:drawable/ic_dialog_email" />

    </android.support.design.widget.CoordinatorLayout>

这是内容xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/content_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/activity_main"
    tools:context="com.example.mysecondapp.myapplication.MainActivity">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true">

        <LinearLayout
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <EditText
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10"
                android:id="@+id/editText2"
                android:layout_weight="1" />

            <Button
                android:text="INSERT"
                android:layout_width="wrap_content"
                android:layout_height="50dp"
                android:id="@+id/button1"
                android:layout_weight="2" />
            <Button
                android:text="ADD"
                android:layout_width="wrap_content"
                android:layout_height="50dp"
                android:id="@+id/button2"
                android:layout_weight="2" />
        </LinearLayout>

    </LinearLayout>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="60dp"/>

</RelativeLayout>

项目xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/item_text_view"/>
</LinearLayout>

代码出了什么问题？

提前致谢

Answer 1

试试这个：我已将LinearLayout的layout_height更改为wrap_content

item.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/item_text_view"/>
    </LinearLayout>

Answer 2

问题是您已将回收器项目的高度设置为与父项匹配，这意味着回收站视图的第一项正在全屏显示。滚动时，您会在底部找到其他项目。

解决此问题

在item.xml中使用

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

而不是

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

为什么Recylerview没有正确显示数据？

2 个答案: