Kotlin和RecyclerView的一个demo

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

    
    <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
     {

        private var context: Context? = null
        private var newsList: ArrayList? = null

        //这是构造方法
        constructor(context: Context, newsList: ArrayList) {
            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): 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): 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 不要积分….