他のドロップダウンを尊重してアンドロイドでドロップダウン

Question

ドロップダウンを2つ作成する方法。どちらが第2のリスト項目に依存するか。

Answer 1

これを試してみてください：

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical"> 

    <Spinner 
     android:id="@+id/spinnerOne" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" /> 

    <Spinner 
     android:id="@+id/spinnerTwo" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" /> 
</LinearLayout> 

MainActivity.java

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener{ 

    String country = ""; 
    ArrayList<String> cityArrayListUSA; 
    ArrayList<String> cityArrayListSpain; 
    Spinner spinnerCountry; 
    Spinner spinnerCity; 
    ArrayAdapter<String> adapterCity; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     spinnerCountry = (Spinner) findViewById(R.id.spinnerOne); 
     spinnerCountry.setOnItemSelectedListener(this); 
     spinnerCity = (Spinner) findViewById(R.id.spinnerTwo); 

     ArrayList<String> countryArrayList = new ArrayList<String>(); 
     countryArrayList.add("USA"); 
     countryArrayList.add("Spain"); 

     cityArrayListUSA = new ArrayList<String>(); 
     cityArrayListUSA.add("New York"); 
     cityArrayListUSA.add("Orlando"); 
     cityArrayListUSA.add("Seattle"); 

     cityArrayListSpain = new ArrayList<String>(); 
     cityArrayListSpain.add("Barcelona"); 
     cityArrayListSpain.add("Madrid"); 
     cityArrayListSpain.add("Cordova"); 

     ArrayAdapter<String> adapterCountry = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,countryArrayList); 
     adapterCountry.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
     spinnerCountry.setAdapter(adapterCountry); 
    } 


    @Override 
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 

     country = parent.getItemAtPosition(position).toString(); 

     if(country.equalsIgnoreCase("Spain")){ 
      adapterCity = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,cityArrayListSpain); 
     } 
     else{ 
      adapterCity = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,cityArrayListUSA); 
     } 
     adapterCity.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
     spinnerCity.setAdapter(adapterCity); 

    } 

    @Override 
    public void onNothingSelected(AdapterView<?> parent) { 

    } 
}