如何在Android中使用CustomAdapter创建Spinner-list [英] How to create Spinner-list using CustomAdapter in android

问题描述

在我的应用中，我想使用CustomAdapter类创建SpinnerList，为此，我在下面的代码中编写了代码，但是当我点击微调器列表时，数组列表图像没有像在我的下方屏幕中那样加载在微调器列表中，为什么出现此问题未来?

in my app,I want to create SpinnerList using CustomAdapter class,For this i wrote below code but when I tap on spinner list then array-List images are not loading in spinner-list as like my below screen why this problem is coming?

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

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dip"
        android:text="Category:"
        android:layout_marginBottom="5dp"/>

    <Spinner
        android:id="@+id/spinner"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

MainActivity:-

public class MainActivity extends AppCompatActivity  {

    public static final String[] titles = new String[] { "Strawberry",
            "Banana", "Orange", "Hello" };

    public static final Integer[] images = { R.drawable.image1,
            R.drawable.image2, R.drawable.image3, R.drawable.image4 };

    Spinner spinner;
    List<RowItem> rowItems;

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

        rowItems = new ArrayList<RowItem>();
        for (int i = 0; i < titles.length; i++) {

            RowItem item = new RowItem(titles[i],images[i]);
            rowItems.add(item);
        }

        spinner = (Spinner)findViewById(R.id.spinner);
       CustomAdapter adapter = new CustomAdapter(MainActivity.this,
            R.layout.listitems_layout, R.id.title, rowItems);
        spinner.setAdapter(adapter);
    }
}

listitems_layout.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"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/icon"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:src="@drawable/image1"
        android:padding="10dp"
        />

    <TextView
        android:layout_marginTop="30dp"
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@+id/icon"
        android:textColor="#CC0033"
        android:text="Strawberry"
        android:textSize="16dp" />

</LinearLayout>

CustomAdapter:-

package com.example.venkat.spinnerexample1;


import android.app.Activity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.view.LayoutInflater;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.List;

public class CustomAdapter extends ArrayAdapter<RowItem> {

    LayoutInflater flater;

     public CustomAdapter(Activity context,int resouceId, int textviewId, List<RowItem> list){

    super(context,resouceId,textviewId, list);
    flater = context.getLayoutInflater();
}

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        RowItem rowItem = getItem(position);

        View rowview = flater.inflate(R.layout.listitems_layout,null,true);

        TextView txtTitle = (TextView) rowview.findViewById(R.id.title);
        txtTitle.setText(rowItem.getTitle());

        ImageView imageView = (ImageView) rowview.findViewById(R.id.icon);
        imageView.setImageResource(rowItem.getImageId());

        return rowview;
    }
}

RowItem:-

package com.example.venkat.spinnerexample1;

public class RowItem {

    private int ImageId;
    private String Title;

    public RowItem(String Title,int ImageId){

        this.Title = Title;
        this.ImageId = ImageId;
    }

    public String getTitle(){

        return Title;
    }

    public void setTitle(String Title){

        this.Title = Title;
    }

    public int getImageId(){

        return ImageId;
    }

    public void setImageId(int ImageId){

        this.ImageId = ImageId;
    }

    @Override
    public String toString() {
        return Title ;
    }
}

屏幕:- ---

推荐答案

在您的适配器构造函数中，还发送textview的ID

Inside your adapter constructor, send the id of textview also

public CustomAdapter(Activity context,int resouceId, int textviewId, List<RowItem> list){

        super(context,resouceId,textviewId, list);
        flater = context.getLayoutInflater();
    }

通过

CustomAdapter adapter = new CustomAdapter(MainActivity.this,
                R.layout.listitems_layout, R.id.title, rowItems);

编辑 由于未覆盖getDropdownView()方法，因此未显示图像.当下拉列表可见时，此方法确定子项的布局.因此，将此方法添加到您的适配器中

EDIT Your images are not showing because you didn't override the getDropdownView() method. This method decides the layout of child when dropdown is visible. So add this method to your adapter

@Override
        public View getDropDownView(int position, View convertView, ViewGroup parent) {
            if(convertView == null){
                convertView = flater.inflate(R.layout.list_itemslayout,parent, false);
            }
            RowItem rowItem = getItem(position);
            TextView txtTitle = (TextView) convertView.findViewById(R.id.title);
            txtTitle.setText(rowItem.getTitle());
            ImageView imageView = (ImageView) convertView.findViewById(R.id.icon);
            imageView.setImageResource(rowItem.getImageId());
            return convertView;
        }

建议 在您的getView()中检查(convertview == null).它可能对这个小型适配器没有任何影响，但是如果您的适配器有更多物品，则会影响性能.

Suggestion in your getView() put a check for (convertview == null). It might not have any impact on this small adapter but in case your adapter is having more items, it will impact the performance.

编辑 要将微调框下拉列表置于锚点下方，请使用

EDIT To put your spinner dropdown below the anchor, use

android:overlapAnchor="false"在微调框内

这篇关于如何在Android中使用CustomAdapter创建Spinner-list的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！