1榜贴、RecyclerView列表布局
在item_view_linear_vertical.xml中:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:orientation="vertical"
android:layout_height="80dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_weight="1"
android:orientation="horizontal"
android:layout_height="0dp">
<ImageView
android:id="@+id/item_image"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_gravity="center_vertical"
android:src="@drawable/ic_launcher_foreground"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:orientation="vertical">
<TextView
android:id="@+id/item_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="地東段減肥標(biāo)題課程"
android:textColor="#000000"
android:textStyle="bold"
android:singleLine="true"
android:maxLines="10"
android:ellipsize="end"
android:textSize="18dp"/>
<TextView
android:id="@+id/item_message"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="6dp"
android:text="內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容內(nèi)容呢絨內(nèi)容"
android:textColor="#666666"
android:textStyle="normal"
android:singleLine="true"
android:ellipsize="end"
android:textSize="14dp"/>
</LinearLayout>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#f3f3f3"/>
</LinearLayout>
在fragment_study.xml中:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".ui.study.StudyFragment">
<TextView
android:id="@+id/text_home"
android:layout_width="match_parent"
android:layout_height="80dp"
android:gravity="center"
android:background="@color/purple_700"
android:textAlignment="center"
android:textSize="20sp"
android:text="LinerLayoutManager列表布局"
android:textColor="@color/white" />
<!-- 要使用RecyclerView, 首先要確保項(xiàng)目–>app–>build.gradle里面
dependencies {
implementation 'androidx.recyclerview:recyclerview:1.0.2'
...
}
-->
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<!-- <androidx.recyclerview.widget.RecyclerView/>-->
</LinearLayout>
在ui-->study-->StudyFragment中:
package com.dbc.bckotlinall.ui.study
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.dbc.bckotlinall.R
import kotlinx.android.synthetic.main.fragment_study.*
import kotlinx.android.synthetic.main.item_view_linear_vertical.view.*
class StudyFragment: Fragment(R.layout.fragment_study) {//關(guān)聯(lián)布局
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
// 需要先安裝擴(kuò)展插件, 就可以直接通過(guò)id名訪問(wèn)控件了
recycler_view.layoutManager = LinearLayoutManager(context,LinearLayoutManager.VERTICAL,false)
recycler_view.adapter = StudyAdapter()
}
// inner 用于聲明StudyAdapter是StudyFragment的內(nèi)部類(lèi)
inner class StudyAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
val itemView = LayoutInflater.from(context).inflate(R.layout.item_view_linear_vertical, parent, false)
return StudyViewHolder(itemView)
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
/// 在代碼中給image控件設(shè)置圖片的三種方式:
holder.itemView.item_image.setImageResource(R.drawable.ic_dashboard_black_24dp)//?
holder.itemView.item_image.setImageDrawable(
ContextCompat.getDrawable(
context!!,// !!表示說(shuō)明此對(duì)象不為空
R.drawable.icon_jetpack
)
)
holder.itemView.item_image.setImageBitmap(BitmapFactory.decodeResource(context!!.resource, R.drawable.icon_jetpack))
holder.itemView.item_title.text="標(biāo)題$position"
holder.itemView.item_message.text="內(nèi)容${position} 能接收到分離焦慮世紀(jì)東方垃圾水電費(fèi)拉伸點(diǎn)擊分類(lèi)計(jì)數(shù)法 打開(kāi)了施法距離卡機(jī)士大夫撒的發(fā)生撒旦法阿斯頓發(fā)安達(dá)市 發(fā)"
}
override fun getItemCount(): Int {
return 20
}
inner class StudyViewHolder(view: View):RecyclerView.ViewHolder(view){
}
}
}
2、GradLayoutManager網(wǎng)格布局
class HomeFragment : Fragment(R.layout.fragment_home){
override fun onViewCreated(view: View, savedInstanceState: Bundle?){
super.onViewCreated(View, savedInstanceState)
recycler_view.layoutManager = LinearLayoutManager(context, 3)//3表示3列
recycler_view.adapter = MyAdapter()
}
// inner: 聲明MyAdapter為HomeFragment的內(nèi)部類(lèi)
inner class MyAdapter: RecyclerView.Adapter<MyViewHolder>(){
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyVIewHolder{
//訪問(wèn)外部類(lèi)的context對(duì)象
val itemView = LayoutInflater.from(context)
.inflate(R.layout.item_view_grid, parent, false)
return MyViewHolder(itemView)
}
// 告訴列表有多少條數(shù)據(jù)
override fun getItemCount(): Int{
return 20
}
//數(shù)據(jù)綁定
override fun onBindViewHolder(holder: MyViewHolder, position: Int){
/// 在代碼中給image控件設(shè)置圖片的三種方式:
holder.itemView.item_image.setImageResource(R.drawable.icon_jetpack)//?
holder.itemView.item_image.setImageDrawable(
ContextCompat.getDrawable(
context!!,// !!表示說(shuō)明此對(duì)象不為空
R.drawable.icon_jetpack
)
)
holder.itemView.item_image.setImageBitmap(BitmapFactory.decodeResource(context!!.resource, R.drawable.icon_jetpack))
}
}
class MyViewHolder(view: View): RecyclerView.ViewHolder(view){
}
}
3畸裳、StaggeredGridLayoutManager瀑布流
recycleView.adapter = MyAdapter()
class HomeFragment : Fragment(R.layout.fragment_home){
override fun onViewCreated(view: View, savedInstanceState: Bundle?){
super.onViewCreated(View, savedInstanceState)
recycler_view.layoutManager = StaggeredGridLayoutMananger(2, StaggeredGridLayoutMananger.VERTICAL)//2表示2列, VERTICAL表示縱向瀑布流
recycler_view.adapter = MyAdapter()
}
// inner: 聲明MyAdapter為HomeFragment的內(nèi)部類(lèi)
inner class MyAdapter: RecyclerView.Adapter<MyViewHolder>(){
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyVIewHolder{
//訪問(wèn)外部類(lèi)的context對(duì)象
val itemView = LayoutInflater.from(context)
.inflate(R.layout.item_view_grid, parent, false)
return MyViewHolder(itemView)
}
// 告訴列表有多少條數(shù)據(jù)
override fun getItemCount(): Int{
return 20
}
//數(shù)據(jù)綁定
override fun onBindViewHolder(holder: MyViewHolder, position: Int){
/// 在代碼中給image控件設(shè)置圖片的三種方式:
holder.itemView.item_image.setImageResource(R.drawable.icon_jetpack)//?
if(position == 0||position == 3||position == 4||position == 7||position == 9){
holder.itemView.item_message.setSingleLine(false)//取消設(shè)置單行顯示
} else {
holder.itemView.item_message.setSingleLine(true)//單行顯示
}
holder.itemView.item_message.text = "xxxxx"
}
}
class MyViewHolder(view: View): RecyclerView.ViewHolder(view){
}
}
4仿吞、快速實(shí)現(xiàn)圓角陰影的組件
// 這一行代碼, 放在頂部layout標(biāo)簽中聲明
xmlns:app="http://schemas.android.com/apk/res-auto"
<androidx.cardview.widget.CardView
android: layout_width = "match_parent"
app:cardBackgroundColor="@color/white"http://設(shè)置背景色
app:CardCornerRadius="10dp"http://設(shè)置圓角
Android: layout_marginLeft="16dp"
Android: layout_marginRight="16dp"
android: layout_height="140dp">
<LinerLayout
android:layout_width="match_parent"
androdi:layout_height="match_parent"
android:orientation="horizontal">
<com.google.android.material.button.MaterialButton
android:id="@+id/item_collect"
android: layout_width="0dp"
style="@style/Widget.MaterialComponents.Button.UnelevatedButton"http://去除按鈕默認(rèn)描邊陰影效果
androdi:layout_height="match_parent"
android:layout_weight="1"
android:backgroundTint="@color/white"
android:text="收藏"
app:icon="@drawable/main_component_my_course_collect"
app:iconGravity="textTop"http://icon位于文字的上方
app:iconSize="25dp"
app:iconTint="@null"http://icon默認(rèn)顏色為白色, 設(shè)置為空顯示原有顏色
android:padding="0dp"http://去除默認(rèn)內(nèi)間距
android:insetTop="0dp"http://去除默認(rèn)留白
android:insetBottom="0dp"http://去除默認(rèn)留白
android:textColor="#333333"/>
...
</LinerLayout>
</androidx.cardview.widget.CardView>
AndroidStudio配置阿里云鏡像 2021.02.25 10:46 2020瀏覽
https://www.imooc.com/article/315290
Mac IDEA配置阿里云國(guó)內(nèi)鏡像 發(fā)布于 2020-07-30
https://segmentfault.com/a/1190000023086534
警告:You have JVM property “https.proxyHost“ set to “127.0.0.1“
http://www.reibang.com/p/9cec82d9498e
5滑频、網(wǎng)絡(luò)請(qǐng)求框架OKHTTP--GET請(qǐng)求
在app->manifests->AndroidManifest.xml添加網(wǎng)絡(luò)訪問(wèn)權(quán)限:
<!-- 請(qǐng)求權(quán)限-->
<uses-permission android:name="android.permission.INTERNET" />
<!-- 寫(xiě)入權(quán)限-->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!-- 讀取權(quán)限-->
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
...
android:usesCleartextTraffic="true" //允許發(fā)起Http請(qǐng)求
....>
</application>
在app/build.gradle的dependencies中添加下面的依賴(lài)
dependencies {
...
implementation("com.squareup.okhttp3:okhttp:4.9.0")
// 網(wǎng)絡(luò)請(qǐng)求日志打印
implementation("com.squareup.okhttp3:logging-interceptor:4.9.0")
}
在http->HiOkHttp中
package com.dbc.bckotlinall.http
import android.util.Log
import okhttp3.Call
import okhttp3.OkHttpClient
import okhttp3.Request
import java.util.concurrent.TimeUnit
// 使用class需要?jiǎng)?chuàng)建實(shí)例對(duì)象
// 使用object的聲明方式, 就沒(méi)有必要構(gòu)建它的實(shí)例對(duì)象了, 直接可以類(lèi).方法調(diào)用
object HiOkHttp {
private val BASE_URL="http://123.56.232.18:8080/serverdemo"
//全局中只有一份
val client = OkHttpClient.Builder() //builder構(gòu)造者設(shè)計(jì)模式
.connectTimeout(10, TimeUnit.SECONDS) //連接超時(shí)時(shí)間
.readTimeout(10, TimeUnit.SECONDS) //讀取超時(shí)
.writeTimeout(10, TimeUnit.SECONDS) //寫(xiě)超時(shí)，也就是請(qǐng)求超時(shí)
.build();
// Android分為主線程和子線程
// 主線程就是APP一啟動(dòng)后, Android framework層會(huì)啟動(dòng)一個(gè)線程, 主線程(UI線程)
// 子線程 -- 可以通過(guò)new Thread().start()創(chuàng)建
//方式一: 同步GET請(qǐng)求
fun get(url: String) {//網(wǎng)絡(luò)請(qǐng)求接口
Thread(Runnable {//開(kāi)啟子線程
//構(gòu)造請(qǐng)求體
val request: Request = Request.Builder()
// .url(url)
.url("$BASE_URL/user/query?userId=1600932269")
.build()
//構(gòu)造請(qǐng)求對(duì)象
val call: Call = client.newCall(request)
// 通過(guò).execute()發(fā)起同步請(qǐng)求--同步執(zhí)行
val response = call.execute()
val body = response.body?.string()
// println("get response :${body}")
Log.e("OKHTTP","get response :${body}")
}).start()
}
//方式二: 異步GET請(qǐng)求
fun getAsync(url: String) {//網(wǎng)絡(luò)請(qǐng)求接口
//構(gòu)造請(qǐng)求體
val request: Request = Request.Builder()
// .url(url)
.url("$BASE_URL/user/query?userId=1600932269")
.build()
//構(gòu)造請(qǐng)求對(duì)象
val call: Call = client.newCall(request)
// 通過(guò).enqueue()發(fā)起異步請(qǐng)求--異步執(zhí)行
call.enqueue(object: Callback {//異步請(qǐng)求沒(méi)有返回值
override fun onFailure(call: Call, e: IOException) {
Log.e("OKHTTP","失敗原因 :${e}")
}
override fun onResponse(call: Call, response: Response) {
val body = response.body?.string()
Log.e("OKHTTP","get response :${body}")
}
})
}
}
在MainActivity.kt中使用:
HiOkHttp.get()
6唤冈、網(wǎng)絡(luò)請(qǐng)求框架OKHTTP--POST請(qǐng)求
http://123.56.232.18:8080/serverdemo/swagger-ui.html#/tag-list-controller/toggleTagFollowUsingPOST
/// 同步表達(dá)提交
fun post(){
val body = FormBody.Builder()
.add("userId","1600932269")
.add("tagId","71")
.build()
val request = Request.Builder().url("$BASE_URL/tag/toggleTagFollow")
.post(body)
.build()
val call = client.newCall(request)
Thread(Runnable {
val response = call.execute()
Log.e("OKHTTP","post response: ${response.body?.string()}")
}).start()
}
/// 異步表單提交
fun postAsync(){
val body = FormBody.Builder()
.add("userId","1600932269")
.add("tagId","71")
.build()
val request = Request.Builder().url("$BASE_URL/tag/toggleTagFollow")
.post(body)
.build()
val call = client.newCall(request)
call.enqueue(object :Callback{
override fun onFailure(call: Call, e: IOException) {
Log.e("OKHTTP","失敗原因 :${e}")
}
override fun onResponse(call: Call, response: Response) {
val body = response.body?.string()
Log.e("OKHTTP","post response :${body}")
}
})
}
/// 異步多表單文件上傳, 在Android6.0以后, 讀取外部存儲(chǔ)卡文件都是需要?jiǎng)討B(tài)申請(qǐng)權(quán)限的
fun postAsyncMultipart(context: Context) {
val file = File(Environment.getExternalStorageDirectory(), "1.png")// 文件目錄, 文件名稱(chēng)
if (!file.exists()) {
Toast.makeText(context, "文件不存在", Toast.LENGTH_SHORT).show()
return
}
val body = MultipartBody.Builder()
.addFormDataPart("key","value")
.addFormDataPart("key1","value1")
.addFormDataPart(
"file",
"1.png",
RequestBody.create("application/octet-stream".toMediaType(), file)
)
.build()
val request = Request.Builder().url("接口是需要支持文件上傳才可以使用的")
.post(body)
.build()
val call = client.newCall(request)
call.enqueue( object : Callback{
override fun onFailure(call: Call, e: IOException) {
Log.e("OKHTTP","失敗原因 :${e}")
}
override fun onResponse(call: Call, response: Response) {
val body = response.body?.string()
Log.e("OKHTTP","postAsyncMultipart response :${body}")
}
})
}
/// 異步POST請(qǐng)求---提交字符串
fun postString(){
///可以是JSON字符串, 也可以是純文本字符串
//純文本
// val textPlain = "text/plain;charset=utf-8".toMediaType()
// val textObj = "{username:admin, password:admin}"
// val body = RequestBody.create(textPlain,textObj)
//Json字符串
val jsonObj = JSONObject()
jsonObj.put("key1","value1")
jsonObj.put("key2",100)
val applicationJson = "application/json;charset=utf-8".toMediaType()
val body = RequestBody.create(applicationJson,jsonObj.toString())
val request = Request.Builder().url("$BASE_URL")
.post(body)
.build()
val call = client.newCall(request)
call.enqueue( object : Callback{
override fun onFailure(call: Call, e: IOException) {
Log.e("OKHTTP","失敗原因 :${e}")
}
override fun onResponse(call: Call, response: Response) {
val body = response.body?.string()
Log.e("OKHTTP","postString response :${body}")
}
})
}
7峡迷、攔截器LoggingInterceptor
使用OkHttp默認(rèn)攔截器
object HiOkHttp {
private val BASE_URL="http://123.56.232.18:8080/serverdemo"
private val client: OkHttpClient
init {
val httpLoggingInterceptor = HttpLoggingInterceptor()
httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY)
client = OkHttpClient.Builder() //builder構(gòu)造者設(shè)計(jì)模式
.connectTimeout(10, TimeUnit.SECONDS) //連接超時(shí)時(shí)間
.readTimeout(10, TimeUnit.SECONDS) //讀取超時(shí)
.writeTimeout(10, TimeUnit.SECONDS) //寫(xiě)超時(shí)，也就是請(qǐng)求超時(shí)
.addInterceptor(httpLoggingInterceptor)//使用默認(rèn)攔截器
.build();
}
....
}
使用自定義攔截器:
/// ①在LoggingInterceptor.kt中:
package com.dbc.bckotlinall.http
import android.util.Log
import okhttp3.Interceptor
import okhttp3.Response
import okhttp3.ResponseBody
import okio.Buffer
/// 攔截器要做的事: 打印攔截請(qǐng)求時(shí)的接口你虹、攜帶哪些參數(shù)
class LoggingInterceptor: Interceptor {
override fun intercept(chain: Interceptor.Chain): Response {
val time_start = System.nanoTime()
val request = chain.request() //獲取request對(duì)象
val response = chain.proceed(request)//獲取response對(duì)象
val buffer = Buffer()
request.body?.writeTo(buffer)
val requestBodyStr = buffer.readUtf8()//把request.body轉(zhuǎn)換成字符串
//打印請(qǐng)求前的: 地址 和 請(qǐng)求參數(shù)
Log.e("OKHTTP",String.format("Sending request %s with params %s",request.url, requestBodyStr))
val bussinessData = response.body?.string()?:"response body null" //讀取輸出流,獲取接口返回的數(shù)據(jù)
/*由于OKHTTP的工作原理: 一旦調(diào)用了response.body?.string()方法, 今后再也不能用response去讀取它的響應(yīng)流了.
*
* 這也就意味著: onResponse回調(diào)函數(shù)中,再次讀取response.body?.string()就會(huì)報(bào)錯(cuò). 這是OKHTTP的工作原理決定的.
*
* 對(duì)于Response響應(yīng)流只能讀取一次的解決辦法是: 返回一個(gè)新的Response.
* */
val mediaType = response.body?.contentType()
val newBody = ResponseBody.create(mediaType, bussinessData)
val newResponse = response.newBuilder().body(newBody).build()
val time_end = System.nanoTime()
//打印請(qǐng)求后的結(jié)果
Log.e("OKHTTP", String.format("Received response for %s in %.1fms >>> %s", request.url,(time_end-time_start)/1e6,bussinessData))
return newResponse
}
}
///②在HiOkHttp中使用:
object HiOkHttp {
private val BASE_URL="http://123.56.232.18:8080/serverdemo"
val client = OkHttpClient.Builder()
.connectTimeout(10, TimeUnit.SECONDS)
.readTimeout(10, TimeUnit.SECONDS)
.writeTimeout(10, TimeUnit.SECONDS)
.addInterceptor(LoggingInterceptor()) //添加自定義攔截器
.build();
...
}
8绘搞、使用Gson來(lái)解析網(wǎng)絡(luò)請(qǐng)求響應(yīng)
在app/build.gradle中添加以下依賴(lài)配置
dependencies {
implementation 'com.google.code.gson:gson:2.8.6'
}
在Account.kt中使用:
package com.dbc.bckotlinall.ui.study
import com.google.gson.Gson
import com.google.gson.reflect.TypeToken
fun main() {
/// 把JSON轉(zhuǎn)換成對(duì)象
val json ="{\"uid\":\"00001\",\"userName\":\"Freeman\",\"telNumber\":\"13000000000\"}"
val gson = Gson()//構(gòu)建gson對(duì)象
// 在kotlin中傳入class類(lèi)型, 需要xxx::class.java 格式
val account:Account = gson.fromJson<Account>(json, Account::class.java)
println("fromJson: ${account.toString()}")
/// 把對(duì)象轉(zhuǎn)換成JSON
val accountJson = gson.toJson(account)
println("toJson: ${accountJson}")
/// 將JSON轉(zhuǎn)換成集合
val jsonList= "[{\"uid\":\"00001\",\"userName\":\"Freeman\",\"telNumber\":\"13000000000\"}]"
val accountList: List<Account> = gson.fromJson(jsonList, object:TypeToken<List<Account>>(){}.type)
println("fromJson to List:${accountList.size}")
/// 將集合轉(zhuǎn)化成JSON
val accountJsonList = gson.toJson(accountList)
println("list to json: ${accountJsonList}")
}
class Account {
/// 在kotlin中必須指定初始值
var uid:String=""
var userName:String=""
var password:String=""
var telNumber:String=""
//?快速生成toString: 首先選中這幾個(gè)字段-->右鍵"Generate"-->選擇"toString()"-->全選
override fun toString(): String {
return "Account(uid='$uid', userName='$userName', password='$password', telNumber='$telNumber')"
}
}
如果對(duì)象模型使用data class, 就可以不用指定初始值了:
data class Account(
var uid:String = "111",
var userName:String,
var password:String,
var telNumber:String
)
使用插件快速生成復(fù)雜的數(shù)據(jù)模型 -- JsonToKotlin插件:
sp1.在網(wǎng)站 https://github.com/wuseal/JsonToKotlinClass/releases/ 下載最新版本zip包
sp2.在AS-->Preferences-->Plugins-->點(diǎn)擊"設(shè)置"按鈕, 選擇"install Plugin from Disk..."--->選擇下載的包,點(diǎn)擊"OK", 重啟IDE
使用插件:
在空白的地方, 右鍵選擇"Generate"-->選擇"Kotlin data classes from JSON"-->將JSON字符串拷貝到這里-->點(diǎn)擊"Format", 輸入"Class Name: xxx", 選擇"Generate" --> 就生成了xxx對(duì)象模型
val userModelJson = "{ ... }"
val userResponse:UserResponse! = gson.fromJson<UserResponse>(userModelJson, UserResponse::class.java)
println("userResponse: $userResponse")
9、RESTFUL網(wǎng)絡(luò)請(qǐng)求框架Retrofit
retrofit注解驅(qū)動(dòng)型上層網(wǎng)絡(luò)請(qǐng)求框架, 使用注解來(lái)簡(jiǎn)化請(qǐng)求, 大體分為以下幾類(lèi):
- 用于標(biāo)注網(wǎng)絡(luò)請(qǐng)求的注解
- 標(biāo)記網(wǎng)絡(luò)請(qǐng)求參數(shù)的注解
- 用于標(biāo)記網(wǎng)絡(luò)請(qǐng)求和響應(yīng)格式的注解
添加依賴(lài):
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0' //json轉(zhuǎn)換
在HiRetrofit.kt中, 封裝Retrofit&定義接口:
package com.dbc.bckotlinall.http
import okhttp3.OkHttpClient
import retrofit2.Call
import retrofit2.Retrofit
import retrofit2.converter.gson.GsonConverterFactory
import retrofit2.http.GET
import retrofit2.http.Query
import java.util.concurrent.TimeUnit
object HiRetrofit {
// https://www.cnblogs.com/hanma/p/14942740.html
private val client = OkHttpClient.Builder() //builder構(gòu)造者設(shè)計(jì)模式
.connectTimeout(10, TimeUnit.SECONDS) //連接超時(shí)時(shí)間
.readTimeout(10, TimeUnit.SECONDS) //讀取超時(shí)
.writeTimeout(10, TimeUnit.SECONDS) //寫(xiě)超時(shí)傅物，也就是請(qǐng)求超時(shí)
.addInterceptor(LoggingInterceptor())
.build();
private val retrofit = Retrofit.Builder()
.client(client)//配置OKHTTP網(wǎng)絡(luò)請(qǐng)求的一個(gè)對(duì)象
.baseUrl("http://123.56.232.18:8080/serverdemo/")//配置網(wǎng)絡(luò)請(qǐng)求的域名
.addConverterFactory(GsonConverterFactory.create())//數(shù)據(jù)轉(zhuǎn)換器: 自動(dòng)轉(zhuǎn)換成數(shù)據(jù)模型
.build();
///定義一個(gè)泛型方法
fun <T> create(clazz: Class<T>): T {
return retrofit.create(clazz)
}
}
/// 定義一個(gè)接口文件, 編寫(xiě)網(wǎng)絡(luò)請(qǐng)求方法
interface APIService{
@GET(value="user/query")
fun queryUser(@Query(value="userId",encoded = true) userId: String):Call<UserResponse>
//UserResponse: 要轉(zhuǎn)換的數(shù)據(jù)模型對(duì)象類(lèi)
}
在MainActivity.kt中使用:
val apiService = HiRetrofit.create(APIService::class.java)
// 此時(shí)onFailure 和 onResponse的回調(diào)都是在主線程的; 但OKHTTP的回調(diào)是在子線程的,如果UI操作還需要回到主線程.
apiService.queryUser("1600932269").enqueue(object: Callback<UserResponse>{
override fun onFailure(call: Call<UserResponse>, t: Throwable) {
Log.e("Retrofit","失敗原因 :${t.message}")
}
override fun onResponse(call: Call<UserResponse>, response: Response<UserResponse>) {
val body = response.body?.string()
Log.e("Retrofit","get response :${body}")
}
})
10夯辖、網(wǎng)絡(luò)圖片的加載
在app/build.gradle中添加以下配置。使用Glide加載圖片
plugins {
...
id 'kotlin-kapt'
}
dependencies {
...
implementation 'com.github.bumptech.glide:glide:4.9.0'
kapt 'com.github.bumptech.glide:compiler:4.9.0'
}
11董饰、數(shù)據(jù)請(qǐng)求與綁定
class StudyFragment: Fragment(R.layout.fragment_study) {//關(guān)聯(lián)布局
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val adapter = StudyAdapter()
recycler_view.layoutManager = LinearLayoutManager(context,LinearLayoutManager.VERTICAL,false)
recycler_view.adapter = adapter
HiRetrofit.create(ApiService::class.java)
.getStudy().enqueue(object: CallBack<List<Course>>{
override fun onFailure(call: Call<List<Course>>, t: Throwable){
Log.e("onFailure:", t.message ?: "unknown error")
}
override fun onResponse(
call: Call<List<Course>>,
response: Response<List<Course>>
){
Log.e("onResponse:", response.body()?.toString() ?: "unknown error")
response.body()?.let{
adapter.setDatas(it)//更新UI
}
}
})
}
inner class StudyAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private val courses = mutableListOf<Course>()
fun setDatas(datas: List<Course>) {
if (datas.isNotEmpty()){
courses.addAll(datas)
notifyDataSetChanged() //這個(gè)命令會(huì)重新執(zhí)行g(shù)etItemCount和onBindViewHolder
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
val itemView = LayoutInflater.from(context).inflate(R.layout.item_view_linear_vertical, parent, false)
return StudyViewHolder(itemView)
}
// 重寫(xiě)執(zhí)行這里才會(huì)刷新
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
val course = courses[position]
// holder.itemView.item_image.setImageResource(R.drawable.ic_dashboard_black_24dp)//本地圖片
//設(shè)置圓角
val options = RequestOptions()
.transform(RoundedCorners(10))//設(shè)置圓角
//添加網(wǎng)絡(luò)圖片
Glide.with(context!!)
.load(course.poster)//設(shè)置圖片地址
.apply ( options )
.into(holder.itemView.item_course_poster)//綁定控件
holder.itemView.item_title.text = course.title
holder.itemView.item_message.text="內(nèi)容${position} "
}
override fun getItemCount(): Int {
return courses.size
}
inner class StudyViewHolder(view: View):RecyclerView.ViewHolder(view){
}
}
}
12楼雹、列表的增刪改查
class StudyFragment: Fragment(R.layout.fragment_study) {//關(guān)聯(lián)布局
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val adapter = StudyAdapter()
recycler_view.layoutManager = LinearLayoutManager(context,LinearLayoutManager.VERTICAL,false)
recycler_view.adapter = adapter
//點(diǎn)擊增加按鈕
tab_add_course.setOnClickListener{
val course = Course(
label = "Android學(xué)習(xí)基礎(chǔ)",
poster = "https://www.songyubao.com/static/book/assets/icon-android.jpeg",
progress = "100%",
title = "Android RecyclerView基礎(chǔ)學(xué)習(xí)"
)
adapter.addCourse(course)
recycler_view.scrollToPosition(0)//滑動(dòng)到第0個(gè)位置
}
//點(diǎn)擊刪除按鈕
tab_delete_course.setOnClickListener{
adapter.deleteCourse(0)
}
//點(diǎn)擊更新按鈕
tab_update_course.setOnClickListener{
adapter.updateCourse(0, "80%")
}
...
}
inner class StudyAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private val courses = mutableListOf<Course>()
fun setDatas(datas: List<Course>) {
if (datas.isNotEmpty()){
courses.addAll(datas)
notifyDataSetChanged() //這個(gè)命令會(huì)重新執(zhí)行g(shù)etItemCount和onBindViewHolder
}
}
fun addCourse(course: Course){
// courses.add(0, course)
// notifyItemChanged(0)
courses.add(course)
//notifyDataSetChanged()//更新整個(gè)列表
notifyItemChanged(courses.size - 1)
}
fun deleteCourse(position: Int){
courses.removeAt(position)
//notifyDataSetChanged()//更新整個(gè)列表
notifyItemRemoved(position)
}
fun updateCourse(position: Int, progress:String){
val course = courses[position]
course.progress = progress
//notifyDataSetChanged()//更新整個(gè)列表
notifyItemChanged(position)
}
...
AS操作小技巧
- 查看Kotlin編譯之后的字節(jié)碼, 有助于我們深入理解kotlin語(yǔ)言, 有兩種方式:
- Shift鍵兩次, 輸入Show kotlin
- Tools->Kotlin->Show Kotlin Bytecode
