ListView项目OnItemClick在ListView适配器中崩溃类

我一直试图让我的列表视图工作相当长一段时间了，我只是改变了我的监听器从onClick到onItemClick来更好地处理listview项目，但应用程序再次崩溃，我的代码如下，任何帮助将不胜感激。ListView项目OnItemClick在ListView适配器中崩溃类

类：

public class ListViewAdapterProduct extends BaseAdapter { 

Context mContext; 
ListView listView = (ListView) findViewById(R.id.listview1); 

listView.setOnItemClickListener(new OnItemClickListener() { 

    @Override 
    public void onItemClick(AdapterView<?> parent, View v, int position, long id){ 

     Resources res = mContext.getResources(); 
     productTitleArray = res.getStringArray(R.array.titles_product); 

     for (String productTitle : productTitleArray) 
     { 
      if(productTitle.equals("productOne")) 
      { 
      Log.d("Msg", "Found"); 
      }    
     else 
      { 
       Log.d("Msg", "Not Found"); 
      } 
     } 
    } 
});

我以前的帖子：

Compare XML String From Java Class When Item In ListView Is Clicked

logcat的：

03-30 16:40:39.027: E/AndroidRuntime(811): FATAL EXCEPTION: main 
03-30 16:40:39.027: E/AndroidRuntime(811): java.lang.NullPointerException 
03-30 16:40:39.027: E/AndroidRuntime(811): at com.twostarii.test.ListViewAdapterproduct.getView(ListViewAdapterproduct.java:91) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.AbsListView.obtainView(AbsListView.java:2159) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.ListView.makeAndAddView(ListView.java:1831) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.ListView.fillDown(ListView.java:674) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.ListView.fillFromTop(ListView.java:735) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.ListView.layoutChildren(ListView.java:1652) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.AbsListView.onLayout(AbsListView.java:1994) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.View.layout(View.java:14008) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewGroup.layout(ViewGroup.java:4373) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1021) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.View.layout(View.java:14008) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewGroup.layout(ViewGroup.java:4373) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.FrameLayout.onLayout(FrameLayout.java:448) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.View.layout(View.java:14008) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewGroup.layout(ViewGroup.java:4373) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1663) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1521) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.LinearLayout.onLayout(LinearLayout.java:1434) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.View.layout(View.java:14008) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewGroup.layout(ViewGroup.java:4373) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.widget.FrameLayout.onLayout(FrameLayout.java:448) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.View.layout(View.java:14008) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewGroup.layout(ViewGroup.java:4373) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1892) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1711) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.Choreographer.doCallbacks(Choreographer.java:562) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.Choreographer.doFrame(Choreographer.java:532) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.os.Handler.handleCallback(Handler.java:725) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.os.Handler.dispatchMessage(Handler.java:92) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.os.Looper.loop(Looper.java:137) 
03-30 16:40:39.027: E/AndroidRuntime(811): at android.app.ActivityThread.main(ActivityThread.java:5041) 
03-30 16:40:39.027: E/AndroidRuntime(811): at java.lang.reflect.Method.invokeNative(Native Method) 
03-30 16:40:39.027: E/AndroidRuntime(811): at java.lang.reflect.Method.invoke(Method.java:511) 
03-30 16:40:39.027: E/AndroidRuntime(811): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
03-30 16:40:39.027: E/AndroidRuntime(811): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
03-30 16:40:39.027: E/AndroidRuntime(811): at dalvik.system.NativeStart.main(Native Method)

活动：

public class MainActivityproduct extends MainActivity { 


ListView list; 
ListViewAdapterproduct adapter; 
EditText editsearch; 
String[] position; 
String[] productTitles; 
String[] productDescriptions; 
int[] images={ 
     R.drawable.list_product_one, 
     R.drawable.list_product_two, 
     R.drawable.list_product_three, 
    }; 


ArrayList<ClassproductList> arraylist = new ArrayList<ClassproductList>(); 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    position = new String[] { "1", "2", "3"}; 

    Resources res = getResources(); 
    productTitles = res.getStringArray(R.array.titles_product); 
    productDescriptions = res.getStringArray(R.array.descriptions_product); 

    list = (ListView) findViewById(R.id.listview1); 

    list.setAdapter(adapter); 

    for (int i = 0; i < position.length; i++) 
    { 
     ClassproductList wp = new ClassproductList(productTitles[i], productDescriptions[i],images[i]); 
     arraylist.add(wp); 
    } 

    adapter = new ListViewAdapterproduct(this, arraylist); 

    list.setAdapter(adapter); 

    editsearch = (EditText) findViewById(R.id.search); 

    editsearch.addTextChangedListener(new TextWatcher() { 

     @Override 
     public void afterTextChanged(Editable arg0) { 
      String text = editsearch.getText().toString().toLowerCase(Locale.getDefault()); 
      adapter.filter(text); 
     } 

     @Override 
     public void beforeTextChanged(CharSequence arg0, int arg1, 
       int arg2, int arg3) { 
     } 

     public void onTextChanged(CharSequence arg0, int arg1, int arg2, 
       int arg3) { 
     } 
    }); 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    getMenuInflater().inflate(R.menu.main, menu); 
    return true; 
}

}

来源

2014-03-30 TwoStarII

崩溃怎么办？有没有可以提供的堆栈跟踪？ –

我发布了logcat，它没有告诉我任何东西，因此我没有发布它，谢谢回复 – TwoStarII

'mContext'为null定义它 – Jack

你有Context mContext;一个问题是空

您的活动

设置mContext = this;所以mContext将是活动context，你将能够使用的资源

这是正确的代码：

因为您已经发送了this在您的适配器中，您需要在那里找到它

public class ListViewAdapterProduct extends BaseAdapter { 

Context mContext; 
ArrayList<ClassproductList> arraylist; 

ListView listView = (ListView) findViewById(R.id.listview1); 

//add this 
public ListViewAdapterProduct (Context mContext,ArrayList<ClassproductList> arraylist) 
{ 
this.mContext = mContext; 

this.arraylist = arraylist; 
}

来源

2014-03-30 16:51:26 Jack

无法正常工作，您应该在哪里定义 – TwoStarII

？我只是用例子编辑我的答案你试过了吗？ – Jack

我看到，你正在一个活动中工作，但是我在一个列表适配器类中工作：public class ListViewAdapterProduct extends BaseAdapter { – TwoStarII

你已经声明了mContext，但是你还没有初始化它。

您可以在适配器的构造做到这一点：

public class ListViewAdapterProduct extends BaseAdapter { 

    Context mContext; 

    // the construcor that initializes the context 
    public ListViewAdapterProduct(Context c){ 
     mContext = c; 
    } 
    ...

但是，你已经张贴的痕迹，认为问题出在你的适配器的getView（）方法，对线91您应该检查也。

ListViewAdapterproduct.getView(ListViewAdapterproduct.java:91)

编辑：

list.setAdapter(adapter);

在该行的适配器为空，你没有初始化...（你设置你的适配器两次，第一次与空）。在本地定义变量并仅在实际需要时才使它们成为类变量是一种很好的做法。这种方式更难忘记初始化。

来源

2014-03-30 17:10:31 kupsef

这是公共查看getView（最终诠释位置，视图视图，ViewGroup父母）{ 没有错误在这里，问题出现时，我改变我的onClick到onItemClick – TwoStarII

看看你的logcat异常跟踪。第一行说NullPointerException在getView（）方法的第91行:) – kupsef

我上面发布我的代码的原因是为了得到详细的帮助，你如何设想我去这 – TwoStarII

已解决!!!

我从onItemClick改回（并发定制适配器使用）来的onClick（简单的自定义适配器使用）和应用：

view.setOnClickListener(new OnClickListener() { 

@Override 
public void onClick(View arg0) { 

    String mytitle=holder.title.getText().toString(); 

    if(mytitle.equals("ProductOne")){ 
     Intent intent1 = new Intent(mContext, ProductClass.ProductOne); 
     mContext.startActivity(intent1); 

     ...   

    } 
}

不得不补充：

String mytitle=holder.title.getText().toString();

来源

2014-04-02 19:24:53 TwoStarII

ListView项目OnItemClick在ListView适配器中崩溃类

回答

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