ANDROID_MARS学习笔记_S02_001_Spinner

Posted 2020-06-13

1.strings.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <resources>
 3 
 4     <string name="app_name">S02_E01_SpinnerEtc</string>
 5     <string name="hello_world">Hello world!</string>
 6     <string name="action_settings">Settings</string>
 7 
 8     <string-array name="planets">
 9         <item>地球</item>
10         <item>火星</item>
11         <item>水星</item>
12         <item>木星</item>
13     </string-array>
14 </resources>

2.activity_main.xml

 1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:paddingBottom="@dimen/activity_vertical_margin"
 6     android:paddingLeft="@dimen/activity_horizontal_margin"
 7     android:paddingRight="@dimen/activity_horizontal_margin"
 8     android:paddingTop="@dimen/activity_vertical_margin"
 9     tools:context="com.example.s02_e01_spinneretc.MainActivity" >
10 
11     <Spinner 
12         android:id="@+id/mSpinner"
13         android:layout_width="match_parent"
14         android:layout_height="wrap_content"/>
15 
16 </RelativeLayout>

3.item.xml自定义下拉项用

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:orientation="vertical"
 4     android:layout_width="fill_parent"
 5     android:layout_height="fill_parent"
 6     >
 7 <TextView  
 8     android:id="@+id/textViewId"
 9     android:layout_width="fill_parent" 
10     android:layout_height="wrap_content" 
11     />
12 </LinearLayout>

4.java

 1 package com.example.s02_e01_spinneretc;
 2 
 3 import android.annotation.SuppressLint;
 4 import android.os.Bundle;
 5 import android.support.v7.app.ActionBarActivity;
 6 import android.view.Menu;
 7 import android.view.MenuItem;
 8 import android.view.View;
 9 import android.widget.AdapterView;
10 import android.widget.AdapterView.OnItemSelectedListener;
11 import android.widget.ArrayAdapter;
12 import android.widget.Spinner;
13 
14 @SuppressLint("NewApi")
15 public class MainActivity extends ActionBarActivity implements OnItemSelectedListener{
16 
17     private Spinner mSpinner;
18     @Override
19     protected void onCreate(Bundle savedInstanceState) {
20         super.onCreate(savedInstanceState);
21         setContentView(R.layout.activity_main);
22         mSpinner = (Spinner) findViewById(R.id.mSpinner);
23         // Create an ArrayAdapter using the string array and a default spinner layout
24         ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.planets, android.R.layout.simple_spinner_item);
25         // Specify the layout to use when the list of choices appears
26         adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
27         // Apply the adapter to the spinner
28         mSpinner.setAdapter(adapter);
29         mSpinner.setPrompt("测试");
30         mSpinner.setOnItemSelectedListener(this);
31     }
32 
33     @Override
34     public boolean onCreateOptionsMenu(Menu menu) {
35         // Inflate the menu; this adds items to the action bar if it is present.
36         getMenuInflater().inflate(R.menu.main, menu);
37         return true;
38     }
39 
40     @Override
41     public boolean onOptionsItemSelected(MenuItem item) {
42         // Handle action bar item clicks here. The action bar will
43         // automatically handle clicks on the Home/Up button, so long
44         // as you specify a parent activity in AndroidManifest.xml.
45         int id = item.getItemId();
46         if (id == R.id.action_settings) {
47             return true;
48         }
49         return super.onOptionsItemSelected(item);
50     }
51 
52     @Override
53     public void onItemSelected(AdapterView<?> parent, View view, int position,
54             long id) {
55         System.out.println(parent.getItemAtPosition(position));
56         
57     }
58 
59     @Override
60     public void onNothingSelected(AdapterView<?> parent) {
61         System.out.println(parent);
62         
63     }
64 }

5.自定义下拉源

 1 package mars.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.View;
 9 import android.widget.AdapterView;
10 import android.widget.ArrayAdapter;
11 import android.widget.Spinner;
12 import android.widget.AdapterView.OnItemSelectedListener;
13 
14 public class MainActivity extends Activity {
15     /** Called when the activity is first created. */
16     //声明Spinner对象
17     private Spinner spinner = null;
18 
19     @Override
20     public void onCreate(Bundle savedInstanceState) {
21         super.onCreate(savedInstanceState);
22         setContentView(R.layout.main);
23         //通过ID，得到Spinner对象
24         spinner = (Spinner) findViewById(R.id.spinnerId);
25         List<String> list = new ArrayList<String>();
26         list.add("test1");
27         list.add("test2");
28         //调用ArrayAdapter的构造函数来创建ArrayAdapter对象
29         //第一个参数是指上下文对象
30         //第二个参数指定了下拉菜单当中每一个条目的样式
31         //第三个参数指定了TextView控件的ID
32         //第四个参数为整个列表提供数据
33         ArrayAdapter adapter = new ArrayAdapter(this,R.layout.item,R.id.textViewId,list);
34         //通过createFromResource方法创建一个ArrayAdapter对象
35         //第一个参数是指上下文对象
36         //第二参数引用了在strings.xml文件当中定义的String数组
37         //第三个参数是用来指定Spinner的样式，是一个布局文件ID，该布局文件由Android系统提供，也可替换为自己定义的布局文件
38         /*ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
39                 this, R.array.planets_array,
40                 android.R.layout.simple_spinner_item);
41 */        //设置Spinner当中每个条目的样式，同样是引用一个Android系统提供的布局文件
42         //adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
43         
44         spinner.setAdapter(adapter);
45         spinner.setPrompt("测试");
46         //为spinner对象绑定监听器
47         spinner.setOnItemSelectedListener(new SpinnerOnSelectedListener());
48     }
49     //这个监听器主要用来监听用户选择列表的动作
50     class SpinnerOnSelectedListener implements OnItemSelectedListener{
51         
52         //当用户选定了一个条目时，就会调用该方法
53         @Override
54         public void onItemSelected(AdapterView<?> adapterView, View view, int position,
55                 long id) {
56             String selected = adapterView.getItemAtPosition(position).toString();
57             System.out.println(selected);
58         }
59 
60         @Override
61         public void onNothingSelected(AdapterView<?> adapterView) {
62             // TODO Auto-generated method stub
63             System.out.println("nothingSelected");
64         }
65         
66     }
67 }