Spinner控件的使用

Spinner 使用方法小结

android里的Spinner其实就是个ComboBox =。=
一。基本使用方法：
main.xml 不多解释

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Spinner
android:id="@+id/mySpinner"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>

在string.xml中使用“string-array”定义数据源。

<?xmlversion="1.0"encoding="utf-8"?>
<resources>
<stringname="app_name">MySpinnerDemo</string>
<string-arrayname="phones_array">
<item>iPhone</item>
<item>Android</item>
<item>BlackBerry</item>
</string-array>
</resources>

Activity类：

packagecom.yinger;

importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.view.View;
importandroid.widget.AdapterView;
importandroid.widget.ArrayAdapter;
importandroid.widget.Spinner;
importandroid.widget.AdapterView.OnItemSelectedListener;

/**
*SpinnerDemo
*@authorYinger
*@time2011-7-9下午01:54:59
*@mailmelody.crazycoding@gmail.com
*/
publicclassSpinnerDemoextendsActivity{
Spinnerspinner=null;
Stringselected="0";

/**Calledwhentheactivityisfirstcreated.*/
@Override
publicvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
spinner=(Spinner)findViewById(R.id.mySpinner);
initMySpinner();
}

privatevoidinitMySpinner(){
ArrayAdapter<CharSequence>adapter=ArrayAdapter.createFromResource(
this,R.array.phones_array,
android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setPrompt("test");
spinner.setOnItemSelectedListener(newSpinnerOnSelectedListener());
}

classSpinnerOnSelectedListenerimplementsOnItemSelectedListener{
publicvoidonItemSelected(AdapterView<?>adapterView,Viewview,intposition,
longid){
//TODOAuto-generatedmethodstub
selected=adapterView.getItemAtPosition(position).toString();
System.out.println("selected===========>"+selected);
}

publicvoidonNothingSelected(AdapterView<?>arg0){
//TODOAuto-generatedmethodstub
System.out.println("selected===========>"+"Nothing");
}
}
}

二。debug发现的一个小问题：
Spinner在初始化时会自动调用一次OnItemSelectedListener事件
原因：有人说是Bug，其实这与C#的事件机制类似，懒得说了=。=
提供的解决办法：
个人是通过在事件注册之前调用

spinner.setSelection(0,true);

但要注意，使用此方法，如果用户选择的也是第一项，那么OnItemSelectedListener事件不会被触发……

三。使用技巧
1.动态添加Spinner的数据源
修改initMySpinner方法，代码如下：

privatevoidinitMySpinner(){
String[]phones={"iPhone","Android","BlackBerry"};
ArrayAdapter<String>adapter=newArrayAdapter<String>(
this,android.R.layout.simple_spinner_item,
phones);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setPrompt("test");
spinner.setSelection(0,true);
spinner.setOnItemSelectedListener(newSpinnerOnSelectedListener());
}

2.自定义Spinner的Layout，替换掉体统默认的android.R.layout.simple_spinner_item
super easy
my_spinner_item.xml:

<?xmlversion="1.0"encoding="utf-8"?>
<TextViewxmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="12dip"
android:textColor="#FF8B1500"
android:gravity="center"/>

修改adapter：

ArrayAdapter<String>adapter=newArrayAdapter<String>(
this,R.layout.my_spinner_item,
phones);

同理，可自定义layout，替换掉android.R.layout.simple_spinner_dropdown_item

3.同时显示图片和文本
自定义Adapter：

packagecom.yinger;

importandroid.content.Context;
importandroid.graphics.Color;
importandroid.view.Gravity;
importandroid.view.View;
importandroid.view.ViewGroup;
importandroid.widget.BaseAdapter;
importandroid.widget.ImageView;
importandroid.widget.LinearLayout;
importandroid.widget.TextView;

/**
*自定义Adapter
*@authorYinger
*@time2011-7-9下午03:39:34
*@mailmelody.crazycoding@gmail.com
*/
publicclassMyAdapterextendsBaseAdapter{

privateContextctx;
privateintdrawableIDs[];
privateintstringIDs[];

publicMyAdapter(Contextctx,intDrawableIDs[],intStringIDs[])
{
this.ctx=ctx;
this.drawableIDs=DrawableIDs;
this.stringIDs=StringIDs;
}

publicintgetCount(){
//TODOAuto-generatedmethodstub
returndrawableIDs.length;
}

publicObjectgetItem(intposition){
//TODOAuto-generatedmethodstub
returndrawableIDs[position];
}

publiclonggetItemId(intposition){
//TODOAuto-generatedmethodstub
returnposition;
}

publicViewgetView(intposition,ViewconvertView,ViewGroupparent){
//TODOAuto-generatedmethodstub
LinearLayoutll=newLinearLayout(ctx);
ll.setOrientation(LinearLayout.HORIZONTAL);
ll.setGravity(Gravity.CENTER_VERTICAL);
ImageViewiv=newImageView(ctx);
iv.setImageResource(drawableIDs[position]);
iv.setLayoutParams(newViewGroup.LayoutParams(100,40));
ll.addView(iv);
TextViewtv=newTextView(ctx);
tv.setText(stringIDs[position]);
tv.setTextSize(14);
tv.setTextColor(Color.BLUE);
ll.addView(tv);
returnll;
}
}

修改initMySpinner方法：

privatevoidinitMySpinner(){
int[]phonePics={R.drawable.apple,R.drawable.android,R.drawable.blackberry};
int[]phones={R.string.iphone,R.string.android,R.string.blackberry};

MyAdapteradapter=newMyAdapter(this,phonePics,phones);
spinner.setAdapter(adapter);
spinner.setPrompt("test");
spinner.setSelection(0,true);
}

OK，但使用自定义的Adapter，我们如何来获取选中的文本信息呢？
在MyAdapter中，修改getView方法，添加黄色区域代码如下：

publicViewgetView(intposition,ViewconvertView,ViewGroupparent){
//TODOAuto-generatedmethodstub
LinearLayoutll=newLinearLayout(ctx);
ll.setOrientation(LinearLayout.HORIZONTAL);
ll.setGravity(Gravity.CENTER_VERTICAL);
ImageViewiv=newImageView(ctx);
iv.setImageResource(drawableIDs[position]);
iv.setLayoutParams(newViewGroup.LayoutParams(100,40));
ll.addView(iv);
TextViewtv=newTextView(ctx);
tv.setText(stringIDs[position]);
tv.setTextSize(14);
tv.setTextColor(Color.BLUE);
tv.setTag("tagTextView");
ll.addView(tv);
returnll;
}

重写事件中的onItemSelected方法：

//TODOAuto-generatedmethodstub
publicvoidonItemSelected(AdapterView<?>adapterView,Viewview,intposition,
longid){
if(adapterView.getId()==R.id.mySpinner)
{
LinearLayoutll=(LinearLayout)view;
TextViewtv=(TextView)ll.findViewWithTag("tagTextView");
Stringstr=(String)tv.getText();
System.out.println("selected===========>"+str);
}
}

最后，别忘了注册该事件。=。=

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