在Android中下载受到尊重的其他下拉列表

Question

如何创建两个下拉列表。其中一个依赖于第二个列表项。

Answer 1

试试这个：

activity_main.xml中

<?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) {

    }
}