Kotlin Moshi Fuel APIからJSONをパースして表示

ライブラリを入手する

Fuel – APIアクセス
Moshi – JSONデータのパース

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.bs_tender">

+   <uses-permission android:name="android.permission.INTERNET" />
+   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.Light.NoActionBar">
        <activity android:name=".MatchListActivity"
                  android:label="マッチリスト"
                  android:theme="@style/AppTheme">
        </activity>
        <activity android:name=".MatchActivity" />
        <activity android:name=".SplashActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".MainActivity" />
        <activity android:name=".SubActivity" />
        <activity android:name=".PicassoActivity" />
    </application>

</manifest>

build.gradle (Module: app)

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.2"
    defaultConfig {
        applicationId "com.example.bs_tender"
        minSdkVersion 15
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.core:core-ktx:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
    implementation "com.fasterxml.jackson.module:jackson-module-kotlin:2.9.+"
    implementation 'com.squareup.picasso:picasso:2.71828'

+   implementation 'com.github.kittinunf.fuel:fuel:1.11.0'
+   implementation 'com.github.kittinunf.fuel:fuel-gson:1.11.0'
+   implementation "com.squareup.moshi:moshi:1.5.0"
+   implementation "com.squareup.moshi:moshi-kotlin:1.5.0"
}

シンプルに検証しよう

jsonを用意した

{"name": "satou","age": "20"}

Activity.ktを用意する

package com.example.bs_tender

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.github.kittinunf.fuel.gson.responseObject
import com.github.kittinunf.fuel.httpGet


class MatchListActivity2 : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_match_list2)

            "https://www.yuulinux.tokyo/demo/bs-tender-server-mock/test.json".httpGet().responseObject<User> { req, res, result ->
                val(user,err) = result
                println("user:${user}")
            }

    }
}


data class User (
    var name: String,
    var age: String
)

これで外部APIにGETでJSONを取得して変数に格納できることがわかりました。

配列のJSONを扱う

リストのJSONを扱うAPIなら。

users.json

[{"user_id": 1,"nickname": "社長","gender_code": 1,"birth_date": "1981/01/13","image_url": "https://www.yuulinux.tokyo/demo/bs-tender-server-mock/cat1.jpg"},
{"user_id": 2,"nickname": "女子","gender_code": 2,"birth_date": "1981/02/13","image_url": "https://www.yuulinux.tokyo/demo/bs-tender-server-mock/cat2.jpg"}]

Activity.kt

package com.example.bs_tender

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.github.kittinunf.fuel.core.ResponseDeserializable
import com.squareup.moshi.Moshi
import com.github.kittinunf.fuel.httpGet
import com.squareup.moshi.JsonAdapter
import com.squareup.moshi.Types


class MatchListActivity2 : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_match_list2)

            val baseUrl: String = "https://www.yuulinux.tokyo/demo/bs-tender-server-mock"
            val endpoint: String = "/match.json"
            val url: String = baseUrl + endpoint

            url.httpGet().responseObject(UserListDeserializer()) { req, res, result ->
                val(users,err) = result
                println("people:${users}")
            }
    }
}

class UserListDeserializer : ResponseDeserializable<List<User>> {

    override fun deserialize(content: String): List<User>? {
        val moshi = Moshi.Builder().build()
        val type = Types.newParameterizedType(List::class.java, User::class.java)
        val listAdapter: JsonAdapter<List<User>> = moshi.adapter(type)

        return listAdapter.fromJson(content)
    }
}

data class User (
    var user_id: Int,
    var nickname: String,
    var gender_dode: Int,
    var birth_date: String,
    var image_url: String
)

@see

JSONパース