はじめに

ReactNativeを使って簡単なアプリは作れた。
では、次は何をするか。

そうAPIを使って情報を取得する。
今回は、ぐるなびAPIを使って、現在地付近の店の情報を取得してみる

https://user.numazu-ct.ac.jp/~tsato/webmap/sphere/coordinates/advanced.html
を使って、現在位置の大まかな緯度と軽度を取得する

（ちなみに筆者の現在位置は大体、北緯35.6度東経139.5度なので、それを以下では使用する）

ぐるなびAPIとは

https://api.gnavi.co.jp/api/
ぐるなびAPIはぐるなびが提供するAPIでぐるなびに掲載されている店舗を
店舗ID、店舗名、店舗名読み、電話番号、住所、地方コードなど全59項目から抽出できる

詳しいリクエストパラメータはこちら

この中から、今回は、現在地周辺の店舗の一覧を取得したいので、緯度、軽度、範囲を使います。

keyidの取得

リクエストパラメータを見ると、唯一の必須項目であるkeyidを取得していきます
https://ssl.gnavi.co.jp/api/regist/?p=input
こちらのページから必要事項を記入して、上記規約に同意し確認画面へを押下して、
しばらくするとアクセスキー(keyid)が記載されたメールが届きます。

アクセスキーと書いてあるところにkeyidが書かれています。
注)個人情報に当たるため、名前とメールアドレスについてはモザイク処理をかけさせていただきました。

どう使うのか？

keyidを取得したのはいいけども、どう使うかがわからない。
そんな方のために、ぐるなびAPIにはテストツールが用意されている。

を見てみると、

keyidのところにすでに値が入っているが、これはテストコードなので、このkeyidをアプリ内でそのまま使うことはできない（はず。。。）

ここで追加を押して、latitude,longitude,rangeを追加してください。
それぞれに、35.6,139,5を入力して、クエリを送信すると、以下の情報を取得できます。

{
    "@attributes": {
        "api_version": "v3"
    },
    "total_hit_count": 10,
    "hit_per_page": 10,
    "page_offset": 1,
    "rest": [
        {
            "@attributes": {
                "order": 0
            },
            "id": "5040316",
            "update_date": "2017-07-26T15:20:09+09:00",
            "name": "たかちゃん食堂",
            "name_kana": "タカチャンショクドウ",
            "latitude": "35.609048",
            "longitude": "139.000295",
            "category": "食堂・定食",
            "url": "https://r.gnavi.co.jp/afp186ba0000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/5040316/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=5040316&q=6"
            },
            "address": "〒409-0502 山梨県大月市富浜町鳥沢1863 ",
            "tel": "0554-26-2400",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "ＪＲ中央本線（東京-塩尻）",
                "station": "鳥沢駅",
                "station_exit": "",
                "walk": "徒歩5",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST01000",
                    ""
                ],
                "category_name_l": [
                    "和食",
                    ""
                ],
                "category_code_s": [
                    "RSFST01001",
                    ""
                ],
                "category_name_s": [
                    "定食・食事処",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 1
            },
            "id": "5257015",
            "update_date": "2018-09-15T05:05:08+09:00",
            "name": "浜田屋食堂",
            "name_kana": "ハマダヤショクドウ",
            "latitude": "35.608923",
            "longitude": "139.004034",
            "category": "食堂・定食",
            "url": "https://r.gnavi.co.jp/hhj6ss1r0000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/5257015/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=5257015&q=6"
            },
            "address": "〒409-0502 山梨県大月市富浜町鳥沢1959 ",
            "tel": "0554-26-5358",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "ＪＲ中央本線（東京-塩尻）",
                "station": "鳥沢駅",
                "station_exit": "",
                "walk": "徒歩4",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST01000",
                    ""
                ],
                "category_name_l": [
                    "和食",
                    ""
                ],
                "category_code_s": [
                    "RSFST01001",
                    ""
                ],
                "category_name_s": [
                    "定食・食事処",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 2
            },
            "id": "5661814",
            "update_date": "2017-08-08T15:25:02+09:00",
            "name": "喜楽",
            "name_kana": "キラク",
            "latitude": "35.609551",
            "longitude": "139.003717",
            "category": "中華料理",
            "url": "https://r.gnavi.co.jp/8tp61xt40000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/5661814/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=5661814&q=6"
            },
            "address": "〒409-0502 山梨県大月市富浜町鳥沢2015-5 ",
            "tel": "0554-26-5033",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "ＪＲ中央本線（東京-塩尻）",
                "station": "鳥沢駅",
                "station_exit": "",
                "walk": "徒歩7",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST14000",
                    ""
                ],
                "category_name_l": [
                    "中華",
                    ""
                ],
                "category_code_s": [
                    "RSFST14007",
                    ""
                ],
                "category_name_s": [
                    "中華料理",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 3
            },
            "id": "7299109",
            "update_date": "2018-06-21T05:18:51+09:00",
            "name": "トゥルシー",
            "name_kana": "トゥルシー",
            "latitude": "35.609220",
            "longitude": "139.007417",
            "category": "サンドイッチ・パン屋",
            "url": "https://r.gnavi.co.jp/cufrutub0000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/7299109/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=7299109&q=6"
            },
            "address": "〒409-0502 山梨県大月市富浜町鳥沢2742-2 ",
            "tel": "0554-68-8152",
            "tel_sub": "",
            "fax": "",
            "opentime": "水～金 11:45～18:00\n土 10:00～16:30",
            "holiday": "",
            "access": {
                "line": "JR中央本線",
                "station": "鳥沢駅",
                "station_exit": "",
                "walk": "徒歩11",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST18000",
                    ""
                ],
                "category_name_l": [
                    "カフェ・スイーツ",
                    ""
                ],
                "category_code_s": [
                    "RSFST18007",
                    ""
                ],
                "category_name_s": [
                    "パン屋・サンドイッチ",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 4
            },
            "id": "6284771",
            "update_date": "2018-01-17T05:04:39+09:00",
            "name": "桂川うどんセンター",
            "name_kana": "カツラガワウドンセンター",
            "latitude": "35.622007",
            "longitude": "138.996081",
            "category": "うどん",
            "url": "https://r.gnavi.co.jp/3fgpck970000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/6284771/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=6284771&q=6"
            },
            "address": "〒409-0502 山梨県大月市富浜町鳥沢8438 桂川ウェルネスパーク里山交流館1F",
            "tel": "0554-20-3080",
            "tel_sub": "",
            "fax": "0554-26-5444",
            "opentime": "月・火・金～日 ランチ・ディナー：11:00～16:00(L.O.15:30)",
            "holiday": "毎週水・木曜日\n※※12月～2月末まで、火曜日、水曜日、木曜日、金曜日がお休みです。",
            "access": {
                "line": "ＪＲ中央本線",
                "station": "鳥沢駅",
                "station_exit": "",
                "walk": "徒歩40",
                "note": ""
            },
            "parking_lots": "70",
            "pr": {
                "pr_short": "桂川うどんセンターで『楽しく！』『美味しく！』",
                "pr_long": "もっちもちでつるつるのうどんは、なんと280円（普通サイズ）。\n天ぷらや温玉などのトッピングも数種類用意しておりますので組み合わせ色々、\nお好みの食べ方でお召し上がり下さい。\nその他に、温玉かつ丼や、カレーライス、カツカレーもあり。\n自然の中でたっぷり遊んだ後は、『桂川うどんセンター』で一休み…\nお子様用の椅子もございますので、子どもから大人まで、ご家族そろってご利用いただけます。"
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST08000",
                    "RSFST01000"
                ],
                "category_name_l": [
                    "ラーメン・麺料理",
                    "和食"
                ],
                "category_code_s": [
                    "RSFST08011",
                    "RSFST08004"
                ],
                "category_name_s": [
                    "ラーメン・麺料理 その他",
                    "カレーうどん"
                ]
            },
            "budget": 500,
            "party": "",
            "lunch": 500,
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 5
            },
            "id": "7331921",
            "update_date": "2018-06-27T05:24:36+09:00",
            "name": "大黒屋",
            "name_kana": "ダイコクヤ",
            "latitude": "35.615374",
            "longitude": "138.980183",
            "category": "そば",
            "url": "https://r.gnavi.co.jp/ew3gfw9d0000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/7331921/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=7331921&q=6"
            },
            "address": "〒409-0614 山梨県大月市猿橋町猿橋55 ",
            "tel": "0554-22-1626",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "ＪＲ中央本線（東京-塩尻）",
                "station": "猿橋駅",
                "station_exit": "北口",
                "walk": "徒歩26",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST08000",
                    ""
                ],
                "category_name_l": [
                    "ラーメン・麺料理",
                    ""
                ],
                "category_code_s": [
                    "RSFST08001",
                    ""
                ],
                "category_name_s": [
                    "そば",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 6
            },
            "id": "5257007",
            "update_date": "2017-08-02T16:08:42+09:00",
            "name": "一松",
            "name_kana": "イチマツ",
            "latitude": "35.613644",
            "longitude": "138.978286",
            "category": "食堂・定食",
            "url": "https://r.gnavi.co.jp/am1a1kn10000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/5257007/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=5257007&q=6"
            },
            "address": "〒409-0614 山梨県大月市猿橋町猿橋150 ",
            "tel": "0554-22-3451",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "JR中央本線（東京-塩尻）",
                "station": "猿橋駅",
                "station_exit": "北口",
                "walk": "徒歩13",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST01000",
                    ""
                ],
                "category_name_l": [
                    "和食",
                    ""
                ],
                "category_code_s": [
                    "RSFST01001",
                    ""
                ],
                "category_name_s": [
                    "定食・食事処",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 7
            },
            "id": "5040315",
            "update_date": "2017-07-26T15:20:08+09:00",
            "name": "仙台屋食堂",
            "name_kana": "センダイヤショクドウ",
            "latitude": "35.615988",
            "longitude": "138.980603",
            "category": "食堂・定食",
            "url": "https://r.gnavi.co.jp/hrxdrw9k0000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/5040315/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=5040315&q=6"
            },
            "address": "〒409-0614 山梨県大月市猿橋町猿橋543 ",
            "tel": "0554-22-3409",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "JR中央本線（東京-塩尻）",
                "station": "猿橋駅",
                "station_exit": "北口",
                "walk": "徒歩18",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST01000",
                    ""
                ],
                "category_name_l": [
                    "和食",
                    ""
                ],
                "category_code_s": [
                    "RSFST01001",
                    ""
                ],
                "category_name_s": [
                    "定食・食事処",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 8
            },
            "id": "7001012",
            "update_date": "2017-08-29T16:58:38+09:00",
            "name": "大月カントリークラブ レストラン",
            "name_kana": "オオツキカントリークラブレストラン",
            "latitude": "35.622641",
            "longitude": "139.009522",
            "category": "食堂・定食",
            "url": "https://r.gnavi.co.jp/sjhkyp5s0000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/7001012/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=7001012&q=6"
            },
            "address": "〒409-0502 山梨県大月市富浜町鳥沢7084 ",
            "tel": "0554-26-5559",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "",
                "station": "",
                "station_exit": "",
                "walk": "",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST01000",
                    ""
                ],
                "category_name_l": [
                    "和食",
                    ""
                ],
                "category_code_s": [
                    "RSFST01001",
                    ""
                ],
                "category_name_s": [
                    "定食・食事処",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        },
        {
            "@attributes": {
                "order": 9
            },
            "id": "5373057",
            "update_date": "2017-08-03T15:32:56+09:00",
            "name": "拓寿司",
            "name_kana": "タクズシ",
            "latitude": "35.607463",
            "longitude": "139.030593",
            "category": "寿司屋",
            "url": "https://r.gnavi.co.jp/nc83d4m80000/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "url_mobile": "http://mobile.gnavi.co.jp/shop/5373057/?ak=u8KuqUlCqbfuD0OFA0v6dDM0ah8UtsVFopA5uS70Phw%3D",
            "coupon_url": {
                "pc": "",
                "mobile": ""
            },
            "image_url": {
                "shop_image1": "",
                "shop_image2": "",
                "qrcode": "https://c-r.gnst.jp/tool/qr/?id=5373057&q=6"
            },
            "address": "〒409-0503 山梨県大月市梁川町綱の上5-1 ",
            "tel": "0554-26-2375",
            "tel_sub": "",
            "fax": "",
            "opentime": "",
            "holiday": "",
            "access": {
                "line": "ＪＲ中央本線（東京-塩尻）",
                "station": "梁川（山梨県）駅",
                "station_exit": "",
                "walk": "徒歩10",
                "note": ""
            },
            "parking_lots": "",
            "pr": {
                "pr_short": "",
                "pr_long": ""
            },
            "code": {
                "areacode": "AREA130",
                "areaname": "中部",
                "prefcode": "PREF19",
                "prefname": "山梨県",
                "areacode_s": "AREAS4765",
                "areaname_s": "大月・上野原・都留",
                "category_code_l": [
                    "RSFST03000",
                    ""
                ],
                "category_name_l": [
                    "すし・魚料理・シーフード",
                    ""
                ],
                "category_code_s": [
                    "RSFST03001",
                    ""
                ],
                "category_name_s": [
                    "寿司",
                    ""
                ]
            },
            "budget": "",
            "party": "",
            "lunch": "",
            "credit_card": "",
            "e_money": "",
            "flags": {
                "mobile_site": 1,
                "mobile_coupon": 0,
                "pc_coupon": 0
            }
        }
    ]
}

アプリに実装する

これをReactNativeに実装する。

実装の仕方については、以下の記事が参考になったので紹介する。
https://facebook.github.io/react-native/docs/network.html

では実装してみる

App.js


fetch('https://api.gnavi.co.jp/RestSearchAPI/v3/?keyid=4187c89207800cb6590d00b934347e7f&latitude=35.6&longitude=139&range=5')
.then(response => response.json())
    .then(responseJson => {
      this.setState(
        {
          isLoading: false,
          elements: responseJson.rest,
        },
        function() {}
      );
    })
    .catch(error => {
      console.error(error);
    });

これによって、elementsの中にAPIのレスポンスコードが全て格納された。

情報を引き出す。

APIによって取得したデータをテキストに起こすやり方は以下の通り

App.js

this.state.elements.map((element, index)=>{
    
    const coords = {
        latitude:Number(element.latitude),
        longitude:Number(element.longitude),
    };
    return (
        <Text>{{element.name}}</Text>
        <Text>{{element.name_kana}}</Text>
        <Text>{{coords.latitude}}</Text>
        <Text>{{coords.longitude}}</Text>
    )
    })

これで、現在地付近のぐるなび掲載店の情報を取得することができる。
このAPIを使って色々と試してみてほしい