Android UI控件-Spinner(下拉列表)

packagecom.example.widgets;

 

importandroid.os.Bundle;

importandroid.app.Activity;

importandroid.view.View;

importandroid.widget.AdapterView;

importandroid.widget.AdapterView.OnItemSelectedListener;

importandroid.widget.ArrayAdapter;

importandroid.widget.Spinner;

importandroid.widget.Toast;

 

publicclass MainActivity extendsActivity {

    privateSpinner spinner;

 

    @Override

    protectedvoid onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        spinner = (Spinner) findViewById(R.id.spinner);

        // 定义一个字符串数组来存储下拉框每个item要显示的文本

        finalString[] items = { "血型", "A型", "B型", "AB型", "O型"};

        // 定义数组适配器，利用系统布局文件

        ArrayAdapter<String> adapter = newArrayAdapter<String>(this,

                android.R.layout.simple_spinner_item, items);

        // 定义下拉框的样式

        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        // 下面的可以直接用适配器添加item(需要把数组适配器最后一个参数去掉)

        // adapter.add("java");

        // adapter.add("android");

        // adapter.add("dotnet");

        // adapter.add("php");

 

        // 设置下拉列表的条目被选择监听器

        spinner.setOnItemSelectedListener(newOnItemSelectedListener() {

 

            @Override

            publicvoid onItemSelected(AdapterView<?> arg0, View arg1,

                    intarg2, longarg3) {

                Toast.makeText(MainActivity.this, items[arg2], 0).show();

 

                // 注意： 这句话的作用是当下拉列表刚显示出来的时候，数组中第0个文本不会显示Toast

                // 如果没有这句话，当下拉列表刚显示出来的时候，数组中第0个文本会显示Toast

                // arg0.setVisibility(View.VISIBLE);

            }

 

            @Override

            publicvoid onNothingSelected(AdapterView<?> arg0) {

                // TODO Auto-generated method stub

 

            }

        });

         

        spinner.setAdapter(adapter);

    }

 

}