Kotlin和RecyclerView的一个demo

水深无声 2022-06-11 09:39 203阅读 0赞

# Kotlin和RecyclerView的一个demo #

> Kotlin最近比较火,我简单学了一下,写了个小demo,RecyclerView的.

## 1.使用到的东西 ##

*  语言:Kotlin [不会配置的点这里….滑稽][.]
 *  RecyclerView
 *  OkHttp3
 *  RxJava
 *  RxAndroid
 *  Glide
 *  Gson

## 2.需要引入的库 ##

implementation 'com.android.support:recyclerview-v7:26.0.0'
    implementation 'com.squareup.okhttp3:okhttp:3.8.1'
    implementation 'io.reactivex.rxjava2:rxjava:2.1.2'
    implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'
    implementation 'com.google.code.gson:gson:2.8.1'
    implementation 'com.github.bumptech.glide:glide:4.0.0'

## 3.首先来看一下RecyclerView子项的布局吧 ##

**item\_news.xml**  
就是一个ImageView和一个TextView

<?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="100dp" android:background="#7dd9da" android:gravity="center_vertical" android:orientation="horizontal">
    
            <ImageView android:id="@+id/iv_news_des" android:layout_width="80dp" android:layout_height="80dp" android:layout_marginStart="10dp" android:scaleType="centerCrop" android:src="@mipmap/ic_launcher"/>
    
            <TextView android:id="@+id/tv_news_title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginStart="10dp" android:ellipsize="end" android:maxLines="1" android:text="震惊...." android:textColor="#AA000000" android:textSize="20sp" />
    
        </LinearLayout>

## 4.model,模型类 ##

/** * description： * author feiyang * create at 2017/8/3 17:37 */
        data class News( @SerializedName("author_name")
                var authorName: String?,
                @SerializedName("category")
                var category: String?,
                @SerializedName("date")
                var date: String?,
                @SerializedName("thumbnail_pic_s")
                var thumbnailPicS: String?,
                @SerializedName("title")
                var title: String?,
                @SerializedName("uniquekey")
                var uniquekey: String?,
                @SerializedName("url")
                var url: String?
    
        )

## 5.adapter(\*重要) ##

/** * description：RecyclerView的adapter * author feiyang * create at 2017/8/3 17:41 */
        class NewsAdapter : RecyclerView.Adapter
        <NewsAdapter.ViewHolder> {
    
            private var context: Context? = null
            private var newsList: ArrayList<News>? = null
    
            //这是构造方法
            constructor(context: Context, newsList: ArrayList<News>) {
                this.context = context
                this.newsList = newsList
            }
    
            class ViewHolder : RecyclerView.ViewHolder {
    
                var ivDes: ImageView
                var tvTitle: TextView
    
                constructor(itemView: View) : super(itemView) {
                    ivDes = itemView.findViewById(R.id.iv_news_des)
                    tvTitle = itemView.findViewById(R.id.tv_news_title)
                }
            }
    
            override fun onBindViewHolder(holder: ViewHolder?, position: Int) {
                if (newsList?.size as Int > position) {
                    val news = newsList?.get(position)
                    //使用Glide加载图片
                    Glide.with(context).load(news?.thumbnailPicS).into(holder?.ivDes)
                    //设置标题
                    holder?.tvTitle?.text = news?.title
                }
            }
    
            override fun getItemCount(): Int {
                return newsList?.size as Int
            }
    
            override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): ViewHolder {
                val view = LayoutInflater.from(parent?.context).inflate(R.layout.item_news, parent, false)
                return ViewHolder(view)
            }
    
            /** * 添加数据 */
            fun addData(dataList: ArrayList<News>): Unit {
                //这里不用像java一样判断空了,这里肯定是非空的
                if (dataList.size == 0) {
                    return
                }
                newsList?.addAll(dataList)
                notifyDataSetChanged()
            }
    
            /** * 更新数据 */
            fun updateData(dataList: ArrayList<News>): Unit {
                if (dataList.size==0) {
                    return
                }
                newsList?.clear()
                newsList?.addAll(dataList)
                notifyDataSetChanged()
            }
    
        }

# 最后 #

核心代码就在上面了,如果想要完整代码的话,去[这里下载][Link 1] 不要积分….

[.]: http://blog.csdn.net/xfhy_/article/details/76654797
[Link 1]: http://download.csdn.net/detail/xfhy_/9920933