自定义Spinner五步走

?

在Android的UI开发中，Spinner(下拉列表)总是可以用到的，一个简单的自定义Spinner制作我们只需要记住这重要的五步，一个Spinner就可以应用而生了。

(1)新建一个Android工程，名字为SpinnerTest1。修改layout下的main.xml，添加一个Textview和一个Spinner，文件内容如下：

1. <?xml?version="1.0"?encoding="utf-8"?>??
2. <LinearLayout??
3. ????android:id="@+id/widget28"??
4. ????android:layout_width="fill_parent"??
5. ????android:layout_height="fill_parent"??
6. ????android:orientation="vertical"??
7. ????xmlns:android="http://schemas.android.com/apk/res/android"?>??
8. ????<TextView??
9. ????????android:id="@+id/TextView_Show"??
10. ????????android:layout_width="fill_parent"??
11. ????????android:layout_height="wrap_content"??
12. ????????android:text="你选择的是"??
13. ????????android:textSize="25sp">??
14. ????</TextView>??
15. ????<Spinner??
16. ????????android:id="@+id/spinner_City"??
17. ????????android:layout_width="fill_parent"??
18. ????????android:layout_height="wrap_content">??
19. ????</Spinner><!--?定义一个下拉菜单-->??
20. </LinearLayout>??

?(2)修改你的SpinnerTest1类，在这里我们就要记住五步来自定义一个Spinner了，完整代码及五步注释如下：

1. package?com.xtlh.spinner;??
2. ??
3. import?java.util.ArrayList;??
4. import?java.util.List;??
5. ??
6. import?android.app.Activity;??
7. import?android.os.Bundle;??
8. import?android.view.MotionEvent;??
9. import?android.view.View;??
10. import?android.view.View.OnTouchListener;??
11. import?android.view.animation.Animation;??
12. import?android.view.animation.AnimationUtils;??
13. import?android.widget.AdapterView;??
14. import?android.widget.ArrayAdapter;??
15. import?android.widget.Spinner;??
16. import?android.widget.TextView;??
17. ??
18. public?class?SpinnerTest1?extends?Activity?{??
19. ????/**?Called?when?the?activity?is?first?created.?*/??
20. ????private?List<String>?list?=?new?ArrayList<String>();??
21. ????private?TextView?myTextView;??
22. ????private?Spinner?mySpinner;??
23. ????private?ArrayAdapter<String>?adapter;??
24. ????private?Animation?myAnimation;??
25. ????@Override??
26. ????public?void?onCreate(Bundle?savedInstanceState)?{??
27. ????????super.onCreate(savedInstanceState);??
28. ????????setContentView(R.layout.main);??
29. ????????//第一步：添加一个下拉列表项的list，这里添加的项就是下拉列表的菜单项??
30. ????????list.add("北京");??
31. ????????list.add("上海");??
32. ????????list.add("深圳");??
33. ????????list.add("南京");??
34. ????????list.add("重庆");??
35. ????????myTextView?=?(TextView)findViewById(R.id.TextView_Show);??
36. ????????mySpinner?=?(Spinner)findViewById(R.id.spinner_City);??
37. ????????//第二步：为下拉列表定义一个适配器，这里就用到里前面定义的list。??
38. ????????adapter?=?new?ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,?list);??
39. ????????//第三步：为适配器设置下拉列表下拉时的菜单样式。??
40. ????????adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);??
41. ????????//第四步：将适配器添加到下拉列表上??
42. ????????mySpinner.setAdapter(adapter);??
43. ????????//第五步：为下拉列表设置各种事件的响应，这个事响应菜单被选中??
44. ????????mySpinner.setOnItemSelectedListener(new?Spinner.OnItemSelectedListener(){??
45. ????????????public?void?onItemSelected(AdapterView<?>?arg0,?View?arg1,?int?arg2,?long?arg3)?{??
46. ????????????????//?TODO?Auto-generated?method?stub??
47. ????????????????/*?将所选mySpinner?的值带入myTextView?中*/??
48. ????????????????myTextView.setText("您选择的是："+?adapter.getItem(arg2));??
49. ????????????????/*?将mySpinner?显示*/??
50. ????????????????arg0.setVisibility(View.VISIBLE);??
51. ????????????}??
52. ????????????public?void?onNothingSelected(AdapterView<?>?arg0)?{??
53. ????????????????//?TODO?Auto-generated?method?stub??
54. ????????????????myTextView.setText("NONE");??
55. ????????????????arg0.setVisibility(View.VISIBLE);??
56. ????????????}??
57. ????????});??
58. ????????/*下拉菜单弹出的内容选项触屏事件处理*/??
59. ????????mySpinner.setOnTouchListener(new?Spinner.OnTouchListener(){??
60. ????????????public?boolean?onTouch(View?v,?MotionEvent?event)?{??
61. ????????????????//?TODO?Auto-generated?method?stub??
62. ????????????????/*?将mySpinner?隐藏，不隐藏也可以，看自己爱好*/??
63. ????????????????v.setVisibility(View.INVISIBLE);??
64. ????????????????return?false;??
65. ????????????}??
66. ????????});??
67. ????????/*下拉菜单弹出的内容选项焦点改变事件处理*/??
68. ????????mySpinner.setOnFocusChangeListener(new?Spinner.OnFocusChangeListener(){??
69. ????????public?void?onFocusChange(View?v,?boolean?hasFocus)?{??
70. ????????//?TODO?Auto-generated?method?stub??
71. ????????????v.setVisibility(View.VISIBLE);??
72. ????????}??
73. ????????});??
74. ????}??
75. }??

??

?记住这五步后，一个Spinner就Ok了，其中在为Spinner的适配器设置下拉时的菜单样式时，我们可以自定义自己的样式，如果嫌麻烦，就直接用android.R.layout的，就如下面这样。
??????? adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);