Android：自定义微调器的自定义适配器下拉xml布局给出错误

我有一个自定义适配器，我用来设置微调器的第一个元素的高度下拉到零的微调。我这样做是为了在我的微调控制器（第一个元素）中有一个默认消息，用户不能点击它，因为它不可见。Android：自定义微调器的自定义适配器下拉xml布局给出错误

package org.digitalhealthagency.elaj.util; 

import java.util.ArrayList; 

import org.digitalhealthagency.elaj.gui.R; 

import android.content.Context; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ArrayAdapter; 
import android.widget.SpinnerAdapter; 
import android.widget.TextView; 

public class CustomAdapter extends ArrayAdapter implements SpinnerAdapter{ 

    Context context; 
    int textViewResourceId; 
    ArrayList arrayList; 

    public CustomAdapter(Context context, int textViewResourceId, ArrayList arrayList) { 
     super(context, textViewResourceId, arrayList); 

     this.context = context; 
     this.textViewResourceId = textViewResourceId; 
     this.arrayList = arrayList; 

    } 

    @Override 
    public View getDropDownView(int position, View convertView, ViewGroup parent){ 
     if (convertView == null) 
     { 
     LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     //convertView = vi.inflate(android.R.layout.simple_spinner_dropdown_item, null); 
     convertView = vi.inflate(R.layout.spinner_item, null); 
     } 

     TextView textView = (TextView) convertView.findViewById(android.R.id.text1); 
     textView.setText(arrayList.get(position).toString());//after changing from ArrayList<String> to ArrayList<Object> 

     if (position == 0) { 
      textView.setHeight(0); 
     } 
     else{ 
     textView.setHeight(100); 
     } 

     return convertView; 
    } 



}

在getDropDownView我试图用spinner_item.xml而不是android.R.layout.simple_spinner_dropdown_item膨胀。我spinner_item如下所示，

<?xml version="1.0" encoding="utf-8"?> 

    <CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android" 
    android:drawableLeft="?android:attr/listChoiceIndicatorSingle" 
    android:gravity="right|center_vertical" 
    android:singleLine="true" 
    android:layout_width="fill_parent" 
    android:layout_height="?android:attr/listPreferredItemHeight" 
    android:paddingRight="10dp" 
    android:ellipsize="marquee" />

而在我的活动代码，我使用适配器如下，

 CustomAdapter adapter = new CustomAdapter(this, R.layout.spinner, subSpecialities); 
     adapter.setDropDownViewResource(R.layout.spinner_item); 
     mSubSpecialtySpinner.setAdapter(adapter);

我得到了我的日志猫以下错误，

07-10 10:49:34.103: E/AndroidRuntime(518): FATAL EXCEPTION: main 
07-10 10:49:34.103: E/AndroidRuntime(518): java.lang.NullPointerException 
07-10 10:49:34.103: E/AndroidRuntime(518): at org.digitalhealthagency.elaj.util.CustomAdapter.getDropDownView(CustomAdapter.java:40) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.Spinner$DropDownAdapter.getDropDownView(Spinner.java:569) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.Spinner$DropDownAdapter.getView(Spinner.java:565) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.AbsListView.obtainView(AbsListView.java:2033) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.ListView.measureHeightOfChildren(ListView.java:1244) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.ListView.onMeasure(ListView.java:1155) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.View.measure(View.java:12723) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.LinearLayout.measureVertical(LinearLayout.java:660) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.LinearLayout.onMeasure(LinearLayout.java:553) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.View.measure(View.java:12723) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.LinearLayout.measureVertical(LinearLayout.java:660) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.LinearLayout.onMeasure(LinearLayout.java:553) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.View.measure(View.java:12723) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.View.measure(View.java:12723) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.View.measure(View.java:12723) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 
07-10 10:49:34.103: E/AndroidRuntime(518): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2092) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.View.measure(View.java:12723) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1064) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.os.Handler.dispatchMessage(Handler.java:99) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.os.Looper.loop(Looper.java:137) 
07-10 10:49:34.103: E/AndroidRuntime(518): at android.app.ActivityThread.main(ActivityThread.java:4424) 
07-10 10:49:34.103: E/AndroidRuntime(518): at java.lang.reflect.Method.invokeNative(Native Method) 
07-10 10:49:34.103: E/AndroidRuntime(518): at java.lang.reflect.Method.invoke(Method.java:511) 
07-10 10:49:34.103: E/AndroidRuntime(518): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
07-10 10:49:34.103: E/AndroidRuntime(518): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
07-10 10:49:34.103: E/AndroidRuntime(518): at dalvik.system.NativeStart.main(Native Method)

任何人都可以帮我吗？

来源

2012-07-10 Nouran H

最多投票，我一直在寻找，我发现它在你的问题的布局！谢谢 – Behzad 2013-05-09 22:28:58

textView is null so NPE ..change它R.id.text1而不是android.R.id.text1

TextView textView = (TextView) convertView.findViewById(android.R.id.text1); 
                 ^^^^^^^^

来源

2012-07-10 09:09:29

另外，TextView没有在XML中设置ID，所以R.id.text1会导致编译或运行时错误（取决于另一个布局文件是否为另一个元素声明ID）。 – ninetwozero 2012-07-10 09:10:21

@ninetwozero非常感谢你，这解决了我的问题:) – 2012-07-10 09:57:31

为了将来的参考，我可以使用android.R.id.text1，如果我使用android：id =“@ android：id/text1”，但如果我提供我自己的ID使用android：id =“@ + id/text1”然后我必须使用R.id.text1 – 2012-07-10 10:55:28

Android：自定义微调器的自定义适配器下拉xml布局给出错误

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