title: How can I connect two pickers as city-district in React-Native?
body: <p>I have a JSON file like so:</p>
  
  <pre class="lang-js prettyprint-override"><code>[
    {
      "city": "Adana",
      "plaka": 1,
      "districts": [
        "Aladağ",
        "Ceyhan",
        "Çukurova",
        "Feke",
        "İmamoğlu",
        "Karaisalı",
        "Karataş",
        "Kozan",
        "Pozantı",
        "Saimbeyli",
        "Sarıçam",
        "Seyhan",
        "Tufanbeyli",
        "Yumurtalık",
        "Yüreğir"
      ]
    },
    {
      "city": "Adıyaman",
      "plaka": 2,
      "districts": [
        "Besni",
        "Çelikhan",
        "Gerger",
        "Gölbaşı",
        "Kahta",
        "Merkez",
        "Samsat",
        "Sincik",
        "Tut"
      ]
    }
   ]
  </code></pre>
  
  <p>I want to use this JSON file but I can't connect pickers. Here is my first picker:</p>
  
  <pre class="lang-js prettyprint-override"><code>&lt;Picker
          selectedValue={this.state.selectedCity}
          onValueChange={(itemValue) =&gt; {
              this.setState({ selectedCity: itemValue });
          }}
      &gt;
      {this.props.cities.map(city =&gt; {
          return (
              &lt;Picker.Item label={city.city} value={city.city} key={city.plaka} /&gt;
          );
      })}
  &lt;/Picker&gt;
  </code></pre>
  
  <p><code>city</code> is my object, <code>city.city</code> is my city name by the way.</p>
  
  <p>If I passed city object to <code>Picker.Item</code> as a value, picker always shows the "Adana" city.</p>