Android cannot find method using onClick button in ListView Row

Question

I have a ListView populated with a custom adapter. Each line has 1 button. In xml, the button has an onClick attribute. I only have xml and not a set of OnClickListeners. Also note that in my CustomActivity there is public void myMethod (View v). I get the following exception

10-02 03:01:46.463: E/AndroidRuntime(26857): java.lang.IllegalStateException: Could not find a method myClickHandler(View) in the activity class **android.app.Application** for onClick handler on view class android.widget.Button with id 'myButton' 

Method in action:

 public void myClickHandler(View v) { ... do stuff here... } 

XML Button:

  <Button android:id="@+id/myButton" android:layout_width="44dp" android:layout_height="44dp" android:background="@drawable/eye_icon" android:onClick="myClickHandler" /> 

An interesting note in Exception is that the application is trying to find the method in android.app.Application , and not in my custom Activity.

Any suggestions?

Answer 1

The important thing is that MyActivity and getContext() of CustomAdapter must be the same instance. Compare yours with mine.

My codes are:

MyActivity.java

 public class MyActivity extends Activity { public static final String TAG = "MyActivity"; private ListView mListView; private CustomAdapter mAdapter; private ArrayList<String> mData; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_my); mListView = (ListView) findViewById(R.id.listView); mData = new ArrayList<String>(); mData.add("111"); mData.add("222"); mData.add("333"); mData.add("444"); mData.add("555"); mAdapter = new CustomAdapter(this, R.layout.list_item_view, mData); mListView.setAdapter(mAdapter); } public void onClickHandler(View view) { Log.i(TAG, "onClickHandler()"); } } 

CustomAdapter.java

 public class CustomAdapter extends ArrayAdapter<String> { public CustomAdapter(Context context, int resource, ArrayList<String> objects) { super(context, resource, objects); } @Override public View getView(int position, View convertView, ViewGroup parent) { if (convertView == null) { LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); convertView = inflater.inflate(R.layout.list_item_view, null); } return convertView; } } 

activity_my.xml

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MyActivity"> <ListView android:id="@+id/listView" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </RelativeLayout> 

list_item_view.xml

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Button" android:id="@+id/button" android:onClick="onClickHandler"/> </LinearLayout> 

Answer 2

When creating a custom Adapter I passed Context result of the getApplicationContext() method. This was wrong. I have to pass this (my custom Activity ) as Context . Now it works like a charm.

Answer 3

I assume that you wrote a custom adapter for this view, so in your adapter, when you call getView, just find the ElementById on the button and set onClickListener there.

Answer 4

This is one example of why the onClick attribute is considered broken. It is probably best to create a custom adapter and manually set OnClickListener in the getView() OnClickListener .