Question

我知道这个问题已被多次讨论过了。我尽我所能，安装了源代码。关键点：我正在使用Google sdk - 10，我正在尝试使用此示例实现微调器：http://developer.android.com/resources/tutorials/views/hello-spinner.html并且仍然存在问题。这是调试消息：

AlertController$RecycleListView(ViewGroup).getChildAt(int) line: 3065

/**
 * Returns the view at the specified position in the group.
 *
 * @param index the position at which to get the view from
 * @return the view at the specified position or null if the position
 *         does not exist within the group
 */
public View getChildAt(int index) {
    try {
        return mChildren[index];
    } catch (IndexOutOfBoundsException ex) {
        return null;
    }
}

这里停止执行：

return mChildren[index];

我做错了什么？

这是主要课程：

package com.hellospinner.test;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

public class HelloSpinnerActivity extends Activity 
{

@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Spinner spinner = (Spinner) findViewById(R.id.spinner);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,  
    R.array.planets_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);
    spinner.setOnItemSelectedListener(new MyOnItemSelectedListener());   
}
}

这是我的OnItemSelectedListener类：

package com.hellospinner.test;

import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Toast;

public class MyOnItemSelectedListener implements OnItemSelectedListener {

public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) 
{ Toast.makeText(parent.getContext(), "The planet is " +  
parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show(); }

public void onNothingSelected(AdapterView parent) 
{  }
}

这是main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dip"        
    android:text="@string/planet_prompt"
    />

<Spinner 
    android:id="@+id/spinner"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:prompt="@string/planet_prompt"
/>


</LinearLayout>

来自strings.xml：

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">HelloSpinner</string>
<string name="planet_prompt">Choose a planet</string>
<string-array name="planets_array">
    <item>Mercury</item>
    <item>Venus</item>
    <item>Earth</item>
    <item>Mars</item>
    <item>Jupiter</item>
    <item>Saturn</item>
    <item>Uranus</item>
    <item>Neptune</item>
</string-array>
</resources>

这里是logcat

Thread [<1> main] (Suspended (exception ArrayIndexOutOfBoundsException))    
AlertController$RecycleListView(ViewGroup).getChildAt(int) line: 3065   
AlertController$RecycleListView(ListView).layoutChildren() line: 1494   
AlertController$RecycleListView(AbsListView).onLayout(boolean, int, int, int, int) line: 1260   
AlertController$RecycleListView(View).layout(int, int, int, int) line: 7175 
LinearLayout.setChildFrame(View, int, int, int, int) line: 1254 
LinearLayout.layoutVertical() line: 1130    
LinearLayout.onLayout(boolean, int, int, int, int) line: 1047   
LinearLayout(View).layout(int, int, int, int) line: 7175    
WeightedLinearLayout(LinearLayout).setChildFrame(View, int, int, int, int) line: 1254   
WeightedLinearLayout(LinearLayout).layoutVertical() line: 1130  
WeightedLinearLayout(LinearLayout).onLayout(boolean, int, int, int, int) line: 1047 
WeightedLinearLayout(View).layout(int, int, int, int) line: 7175    
FrameLayout.onLayout(boolean, int, int, int, int) line: 338 
FrameLayout(View).layout(int, int, int, int) line: 7175 
PhoneWindow$DecorView(FrameLayout).onLayout(boolean, int, int, int, int) line: 338  
PhoneWindow$DecorView(View).layout(int, int, int, int) line: 7175   
ViewRoot.performTraversals() line: 1140 
ViewRoot.handleMessage(Message) line: 1859  
ViewRoot(Handler).dispatchMessage(Message) line: 99 
Looper.loop() line: 130 
ActivityThread.main(String[]) line: 3683    
Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]  
Method.invoke(Object, Object...) line: 507  
ZygoteInit$MethodAndArgsCaller.run() line: 839  
ZygoteInit.main(String[]) line: 597 
NativeStart.main(String[]) line: not available [native method]

Eclipse IDE上的Android和微调器

0 个答案: