OkHttp入门与实践

1. 添加OkHttp依赖

在Android项目中引入OkHttp库，是实现网络请求的重要前提。这一步可以通过以下方式完成：

implementation 'com.squareup.okhttp3:okhttp:3.10.0'

2. 占位请求

异步请求实现

private void useAsynGet() {
    val okHttpClient = OkHttpClient()
    val url = "http://www.qq.com"
    val request = Request.Builder().url(url).get().build()
    val call = okHttpClient.newCall(request)
    call.enqueue(object : Callback {
        override fun onFailure(call: Call, e: IOException) {
            Log.e("useAsynGet", e.toString())
        }
        override fun onResponse(call: Call, response: okhttp3.Response): Unit {
            val content = response.body().string()
            Log.e("useAsynGet", content)
            // 在子线程处理，通过Handler发送消息到主线程
            val message = Message()
            message.what = MSG_WEB_CONTENT
            message.obj = content
            handler.sendMessage(message)
        }
    })
}

同步请求实现

private void useSyncGet() {
    val okHttpClient = OkHttpClient()
    val url = "http://www.qq.com"
    val request = Request.Builder().url(url).get().build()
    val call = okHttpClient.newCall(request)
    Thread {
        try {
            val response = call.execute()
            val content = response.body().string()
            Log.e("useSyncGet", content)
        } catch (e: IOException) {
            e.printStackTrace()
        }
    }.start()
}

3. 显示网络内容

为了确保UI更新在主线程 انجام.Foundation历 dequeueReusableCellWithIdentifier(“MSG_WEB_CONTENT”) 来处理消息。

4. OkHttp获取移动电源码

private void useAsynGetMobileCode() {
    val okHttpClient = OkHttpClient()
    val url = "http://ws.webxml.com.cn/WebServices/MobileCodeWS.asmx/getMobileCodeInfo"
    // 注意：实际使用应根据接口文档调整参数
    val request = Request.Builder().url(url).get().build()
    val call = okHttpClient.newCall(request)
    call.enqueue(object : Callback {
        override fun onFailure(call: Call, e: IOException) {
            Log.e("useAsynGetMobileCode", e.toString())
        }
        override fun onResponse(call: Call, response: okhttp3.Response): Unit {
            val content = response.body().string()
            Log.e("useAsynGetMobileCode", content)
            // 通过Handler发送消息到主线程
            val message = Message()
            message.what = MSG_WEB_CONTENT
            message.obj = content
            handler.sendMessage(message)
        }
    })
}

5. OkHttp POST 请求

private void useOkhttpPost() {
    val url = "http://ws.webxml.com.cn/WebServices/MobileCodeWS.asmx/getMobileCodeInfo"
    // 参数通过FormBodyBuilder构建
    val requestBody = FormBody.Builder()
        .add("mobileCode", "13456789999")
        .add("userID", "")
        .build()
    val okHttpClient = OkHttpClient()
    val request = Request.Builder().url(url).post(requestBody).build()
    val call = okHttpClient.newCall(request)
    call.enqueue(object : Callback {
        override fun onFailure(call: Call, e: IOException) {
            Log.e("useOkhttpPost", e.toString())
        }
        override fun onResponse(call: Call, response: okhttp3.Response): Unit {
            val content = response.body().string()
            Log.e("useOkhttpPost", content)
            // 发送消息到主线程
            val message = Message()
            message.what = MSG_WEB_CONTENT
            message.obj = content
            handler.sendMessage(message)
        }
    })
}

6. OkHttp 获取图片

private void useOkhttpGetImage() {
    val url = "http://www.gdcp.edu.cn/service?token=5a5d0c3fa9a145719be5b98f7b49eb56"
    val okHttpClient = OkHttpClient()
    val request = Request.Builder().url(url).get().build()
    val call = okHttpClient.newCall(request)
    call.enqueue(object : Callback {
        override fun onFailure(call: Call, e: IOException) {
            Log.e("useOkhttpGetImage", e.toString())
        }
        override fun onResponse(call: Call, response: okhttp3.Response): Unit {
            Log.e("useOkhttpGetImage", response.message())
            val inputStream = response.body().byteStream()
            val bitmap = BitmapFactory.decodeStream(inputStream)
//            {/*此处在子线程处理，需通过Handler发送到主线程*/}
            val message = Message()
            message.what = MSG_GET_IMG
            message.obj = bitmap
            handler.sendMessage(message)
        }
    })
}

初始化Handler

private val handler: Handler by lazy {
    Handler(object : Handler.Callback {
        override fun handleMessage(msg: Message): Boolean {
            when (msg.what) {
                MSG_WEB_CONTENT -> {
                    val content = msg.obj as String
                    tv_show.text = content
                    return true
                }
                MSG_GET_IMG -> {
                    val bitmap = msg.obj as Bitmap
                    iv_show.setImageBitmap(bitmap)
                    return true
                }
            }
            return false
        }
    })
}