Android ListView 实例讲解清晰易懂

一、前言

在某些场景下，单一文字的listview item已不适合当前需求，因此需要我们自定义item布局来满足需求。下面我们来实现一个带图标和文字的item。

二、代码展示

1.定义包含listview的布局文件activity_main.xml，activity在oncreate()时加载。

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.constraintlayout 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:background="#ffe4c4"
    tools:context=".mainactivity">

    <linearlayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margintop="10dp"
        android:layout_marginleft="10dp"
        android:layout_marginright="10dp"
        android:layout_marginbottom="10dp"
        android:background="#e4dddd">

        <listview
            android:id="@+id/listview"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    </linearlayout>

</androidx.constraintlayout.widget.constraintlayout>

2.定义item布局文件listview_item.xml，创建simpleadapter对象时使用。

<?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="match_parent"
    android:orientation="horizontal"
    android:background="#f0fff0">

    <imageview
        android:id="@+id/imageview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1"/>

    <textview
        android:id="@+id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="7"
        android:textcolor="#ff6e40"
        android:textsize="24sp"
        android:textstyle="bold" />



</linearlayout>

3.完善mainactivity.java代码。

package com.example.listviewdemo2;

import androidx.appcompat.app.appcompatactivity;

import android.os.bundle;
import android.widget.listview;
import android.widget.simpleadapter;

import java.util.arraylist;
import java.util.hashmap;
import java.util.list;
import java.util.map;

public class mainactivity extends appcompatactivity {

    private listview mlistview = null;
    private list<map<string, object>> mlistitems = null;
    private map<string, object> mmap = null;

    private simpleadapter madapter = null;

    /* 图片id数组 */
    private int[] mimageid = new int[] {r.drawable.num_0, r.drawable.num_1, r.drawable.num_2, r.drawable.num_3, r.drawable.num_4,
                                        r.drawable.num_5, r.drawable.num_6, r.drawable.num_7, r.drawable.num_8, r.drawable.num_9, };
    /* 文字列表数组 */
    private string[] mtitle = new string[] {"数字 0", "数字 1", "数字 2", "数字 3", "数字 4", "数字 5", "数字 6", "数字 7", "数字 8", "数字 9", };

    @override
    protected void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.activity_main);

        init();
    }

    private void init() {
        mlistview = findviewbyid(r.id.listview);

        mlistitems = new arraylist<>();
        for (int i = 0; i < mimageid.length; i++) {
            mmap = new hashmap<>();
            mmap.put("image", mimageid[i]);
            mmap.put("title", mtitle[i]);
            mlistitems.add(mmap);
        }

        madapter = new simpleadapter(this, mlistitems, r.layout.listview_item, new string[]{"title", "image"}, new int[]{r.id.textview, r.id.imageview});
        mlistview.setadapter(madapter);
    }
}