【38】kotlin 协程异步下载图片1

原创

mp624183768 2023-03-10 15:34:25 ©著作权

文章标签 java Data ooc 文章分类 JavaScript 前端开发

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新增依赖

implementation 'com.squareup.retrofit2:retrofit:2.3.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.3.0'

新建ui包

新建MainKt.kt

package cn.kotliner.coroutine.ui


import cn.kotliner.coroutine.common.HttpError
import cn.kotliner.coroutine.common.HttpService
import cn.kotliner.coroutine.common.log
import okhttp3.ResponseBody
import retrofit2.Call
import retrofit2.Callback
import retrofit2.HttpException
import retrofit2.Response
import javax.swing.JFrame.EXIT_ON_CLOSE
import javax.swing.SwingUtilities

/**
 * Created by benny on 5/20/17.
 */
const val LOGO_URL = "http://www.imooc.com/static/img/index/logo.png?t=1.1"

fun main(args: Array<String>) {
    val frame = MainWindow()
    frame.title = "Coroutine@Bennyhuo"
    frame.setSize(200, 150)
    frame.isResizable = true
    frame.defaultCloseOperation = EXIT_ON_CLOSE
    frame.init()
    frame.isVisible = true

//    frame.onButtonClick {
//        log("协程之前")
//        我要开始协程啦(DownloadContext(LOGO_URL)) {
//            log("协程开始")
//            try {
//                val imageData = 我要开始耗时操作了 {
//                    我要开始加载图片啦(this[DownloadContext]!!.url)
//                }
//                log("拿到图片")
//                frame.setLogo(imageData)
//            } catch(e: Exception) {
//                e.printStackTrace()
//            }
//        }
//        log("协程之后")
//    }

    frame.onButtonClick {
        HttpService.service.getLogo(LOGO_URL)
            .enqueue(object : Callback<ResponseBody> {
                override fun onResponse(
                    call: Call<ResponseBody>,
                    response: Response<ResponseBody>) {
                    if (response.isSuccessful) {
                        val imageData = response.body()?.byteStream()?.readBytes()
                        if (imageData == null) {
                        } else {
                            SwingUtilities.invokeLater {
                                frame.setLogo(imageData)
                            }
                        }
                    } else {
                    }
                }

                override fun onFailure(call: Call<ResponseBody>, t: Throwable) {
                }

            })
    }
}

新建 MainWindow.java

package cn.kotliner.coroutine.ui

import java.awt.BorderLayout
import java.awt.Dimension
import java.awt.event.ActionEvent
import javax.swing.*


/**
 * Created by benny on 5/20/17.
 */
class MainWindow : JFrame() {

    private lateinit var button: JButton
    private lateinit var image: JLabel

    fun init() {
        button = JButton("点我获取慕课网Logo")
        image = JLabel()
        image.size = Dimension(200, 80)

        contentPane.add(button, BorderLayout.NORTH)
        contentPane.add(image, BorderLayout.CENTER)
    }

    fun onButtonClick(listener: (ActionEvent) -> Unit) {
        button.addActionListener(listener)
    }

    fun setLogo(logoData: ByteArray) {
        image.icon = ImageIcon(logoData)
    }
}

新建包common

新建HttpService.kt

package cn.kotliner.coroutine.common

/**
 * Created by benny on 5/20/17.
 */
import okhttp3.ResponseBody


/**
 * Created by benny on 5/20/17.
 */
object HttpService {

    val service by lazy{
        val retrofit = retrofit2.Retrofit.Builder()
                .baseUrl("http://www.imooc.com")
                .addConverterFactory(retrofit2.converter.gson.GsonConverterFactory.create())
                .build()

        retrofit.create(cn.kotliner.coroutine.common.Service::class.java)
    }

}

interface Service{

    @retrofit2.http.GET
    fun getLogo(@retrofit2.http.Url fileUrl: String): retrofit2.Call<ResponseBody>

}