Android 控件之Spinner

Spinner用来显示列表项，类似于一组单选框RadioButton.下面瞥一下它的效果。

一、概述

Spinner是一个每次只能选择所有项的一个项的控件。它的项来自于与之相关联的适配器中。

二、重要属性

android:prompt：当Spinner对话框关闭时显示该提示

三、重要方法

setPrompt(CharSequence prompt)：设置当Spinner对话框关闭时显示的提示

performClick()：如果它被定义就调用此视图的OnClickListener

setOnItemClickListener(AdapterView.OnItemClickListener l)：当项被点击时调用

onDetachedFromWindow()：当Spinner脱离窗口时被调用。

四、完整代码

public class SpinnerDemo extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.spinnerpage);
        Spinner s1 = (Spinner) findViewById(R.id.spinnercolor);
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
                this, R.array.colors, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        s1.setAdapter(adapter);
        s1.setOnItemSelectedListener(
                new OnItemSelectedListener() {
                    public void onItemSelected(
                            AdapterView<?> parent, View view, int position, long id) {
                        showToast("Spinner1: position=" + position + " id=" + id);
                    }
                    public void onNothingSelected(AdapterView<?> parent) {
                        showToast("Spinner1: unselected");
                    }
                });
        Spinner s2 = (Spinner) findViewById(R.id.spinnerplanet);
        adapter = ArrayAdapter.createFromResource(this, R.array.planets,
                android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        s2.setAdapter(adapter);
        s2.setOnItemSelectedListener(
                new OnItemSelectedListener() {
                    public void onItemSelected(
                            AdapterView<?> parent, View view, int position, long id) {
                        showToast("Spinner2: position=" + position+1 + " id=" + id+1);
                    }
                    public void onNothingSelected(AdapterView<?> parent) {
                        showToast("Spinner2: unselected");
                    }
                });
    }
   
    private void showToast(CharSequence msg) {
        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
    }
}