片段中的自定义列表适配器
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【中文标题】片段中的自定义列表适配器【英文标题】：Custom List adapter in Fragment 【发布时间】：2020-01-10 02:31:39 【问题描述】：我目前正在尝试为我的 Fragment 实现自定义 listView，但是当我尝试将项目添加到 ListView 时，它没有显示，并且我没有得到任何异常或任何东西。
我正在尝试做的是通过键入创建一个具有名称和数字的对象，这两种方法都有效，但似乎我在 listView 上犯了一个错误
这是带有 ListView 的片段
package com.example.myapplicationteeeeeeeeeest.ui.BShoppingRecipe;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import com.example.myapplicationteeeeeeeeeest.R;
import java.util.ArrayList;
import java.util.List;
public class ShoppingListTab extends ShoppingRecipe
private EditText inputIngredient;
private EditText inputQuantity;
private Button addButton;
private ListView listView;
private ShoppingListAdapter adapterListView;
private ArrayList<ShoppingList> ShoppingList;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
View view = inflater.inflate( R.layout.tab_fragment_one, container,false );
listView = (ListView) view.findViewById( R.id.shoppingList_listView );
addButton = (Button) view.findViewById( R.id.shoppingTab_button);
inputQuantity = (EditText) view.findViewById( R.id.quantity_editText );
inputIngredient = (EditText) view.findViewById( R.id.ingredient_editText );
ShoppingList = new ArrayList<>();
adapterListView = new ShoppingListAdapter( getActivity(),ShoppingList );
listView.setAdapter( adapterListView );
listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener()
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id)
ShoppingList.remove(position);
adapterListView.notifyDataSetChanged();
return true;
);
addButton.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
String ingredient = inputIngredient.getText().toString().trim();
String quantitiy = inputQuantity.getText().toString().trim();
if (!ingredient.isEmpty() && !quantitiy.isEmpty())
ShoppingList ShoppingListItem = new ShoppingList(ingredient, quantitiy);
ShoppingList.add(ShoppingListItem);
adapterListView.notifyDataSetChanged();
inputIngredient.setText("");
inputQuantity.setText("");
);
return view;
片段布局
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_
android:layout_>
<EditText
android:id="@+id/ingredient_editText"
android:layout_
android:layout_
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="80dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:ems="10"
android:hint="@string/shopping_list_hint_artikel"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/quantity_editText"
android:layout_
android:layout_
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:ems="10"
android:hint="@string/shopping_list_hint_stückzahl"
android:inputType="number"
app:layout_constraintEnd_toStartOf="@+id/shoppingTab_button"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/ingredient_editText"
app:layout_constraintHorizontal_bias="0.0"/>
<Button
android:id="@+id/shoppingTab_button"
android:layout_
android:layout_
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:text="@string/shopping_list_button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@id/ingredient_editText" />
<ListView
android:id="@+id/shoppingList_listView"
android:layout_
android:layout_
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/quantity_editText"/>
</androidx.constraintlayout.widget.ConstraintLayout>
服装列表适配器
package com.example.myapplicationteeeeeeeeeest.ui.BShoppingRecipe;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import com.example.myapplicationteeeeeeeeeest.R;
import java.util.ArrayList;
public class ShoppingListAdapter extends ArrayAdapter<ShoppingList>
private ArrayList<ShoppingList> shoppingList;
private Context context;
public ShoppingListAdapter(Context context, ArrayList<ShoppingList> taskList)
super(context, R.layout.shopping_list_item);
this.shoppingList = taskList;
this.context = context;
@Override
public View getView(int position, View convertView, ViewGroup parent)
View v = convertView;
if(v == null)
LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = layoutInflater.inflate(R.layout.shopping_list_item, null);
ShoppingList taskItem = shoppingList.get(position);
if(taskItem != null)
TextView taskItemText = v.findViewById(R.id.shoppingList_Ingredient);
TextView taskItemDate = v.findViewById(R.id.shoppingList_Quantity);
taskItemText.setText(taskItem.getTask());
taskItemDate.setText(taskItem.getNumber());
return v;
以及项目的布局
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_
android:layout_
xmlns:app="http://schemas.android.com/apk/res-auto"
>
<TextView
android:text="TextView"
android:layout_
android:layout_
android:id="@+id/shoppingList_Ingredient"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginLeft="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toStartOf="@+id/shoppingList_Quantity"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"/>
<TextView
android:text="TextView"
android:layout_
android:layout_
android:id="@+id/shoppingList_Quantity"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginTop="8dp"
app:layout_constraintTop_toTopOf="parent"/>
</android.support.constraint.ConstraintLayout>
【问题讨论】：
【参考方案1】：尝试在您的适配器类中添加此方法：
@Override
public int getCount()
return shoppingList.size();
并且也尽量不要为您的列表变量和模型类使用相同的名称。 希望这会有所帮助！
【讨论】：
我还需要将项目的布局更改为 但后来它工作了，非常感谢您的帮助以上是关于片段中的自定义列表适配器的主要内容，如果未能解决你的问题，请参考以下文章
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