Recently, someone in the communication group asked a question: How to respond to the click event of the ListView internal button in Activity, and not respond in Adapter?
For this question, my initial answer was to define a callback interface in Adapter and implement it in Activity to achieve response to click events.
After get off work, I thought about it and felt that there are two ways to implement it better: using interface callbacks and using abstract class callbacks.
It just so happened that we can review the difference between interfaces and abstract classes, so we wrote two demos:
1. Use interface callback:
Adapter class
package ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
public class ContentAdapter extends BaseAdapter implements OnClickListener {
private static final String TAG = "ContentAdapter";
private List<String> mContentList;
private LayoutInflater mInflater;
private Callback mCallback;
/**
* Custom interface for callback button click event to Activity
* @author Ivan Xu
* 2014-11-26
*/
public interface Callback {
public void click(View v);
}
public ContentAdapter(Context context, List<String> contentList,
Callback callback) {
mContentList = contentList;
mInflater = (context);
mCallback = callback;
}
@Override
public int getCount() {
(TAG, "getCount");
return ();
}
@Override
public Object getItem(int position) {
(TAG, "getItem");
return (position);
}
@Override
public long getItemId(int position) {
(TAG, "getItemId");
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
(TAG, "getView");
ViewHolder holder = null;
if (convertView == null) {
convertView = (.list_item, null);
holder = new ViewHolder();
= (TextView) convertView
.findViewById(.textView1);
= (Button) (.button1);
(holder);
} else {
holder = (ViewHolder) ();
}
((position));
(this);
(position);
return convertView;
}
public class ViewHolder {
public TextView textView;
public Button button;
}
//Respond to button click event, call the sub-definition interface, and pass in View @Override
public void onClick(View v) {
(v);
}
}
Activity class:
package ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
//MainActivity needs to implement a custom interfacepublic class MainActivity extends Activity implements OnItemClickListener,
Callback {
// Simulate the data loaded in the listview private static final String[] CONTENTS = { "Beijing", "Shanghai", "Guangzhou", "Shenzhen", "Suzhou",
"Nanjing", "Wuhan", "Changsha", "Hangzhou" };
private List<String> contentList;
private ListView mListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
(savedInstanceState);
setContentView(.activity_main);
init();
}
private void init() {
mListView = (ListView) findViewById();
contentList = new ArrayList<String>();
for (int i = 0; i < ; i++) {
(CONTENTS[i]);
}
//
(new ContentAdapter(this, contentList, this));
(this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(, menu);
return true;
}
/**
* Respond to the click event of the item in ListView
*/
@Override
public void onItemClick(AdapterView<?> arg0, View v, int position, long id) {
(this, "The item of listview was clicked!, the clicked position is -->" + position,
Toast.LENGTH_SHORT).show();
}
/**
* Interface method, responding to ListView button click event
*/
@Override
public void click(View v) {
(
,
"The button inside the listview was clicked!, the position is -->" + (Integer) () + ",The content is -->"
+ ((Integer) ()),
Toast.LENGTH_SHORT).show();
}
}
2. Use abstract class callbacks
Adapter class:
package ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
public class ContentAdapter extends BaseAdapter {
private static final String TAG = "ContentAdapter";
private List<String> mContentList;
private LayoutInflater mInflater;
private MyClickListener mListener;
public ContentAdapter(Context context, List<String> contentList,
MyClickListener listener) {
mContentList = contentList;
mInflater = (context);
mListener = listener;
}
@Override
public int getCount() {
(TAG, "getCount");
return ();
}
@Override
public Object getItem(int position) {
(TAG, "getItem");
return (position);
}
@Override
public long getItemId(int position) {
(TAG, "getItemId");
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
(TAG, "getView");
ViewHolder holder = null;
if (convertView == null) {
convertView = (.list_item, null);
holder = new ViewHolder();
= (TextView) convertView
.findViewById(.textView1);
= (Button) (.button1);
(holder);
} else {
holder = (ViewHolder) ();
}
((position));
(mListener);
(position);
return convertView;
}
public class ViewHolder {
public TextView textView;
public Button button;
}
/**
* Abstract class for callbacks
* @author Ivan Xu
* 2014-11-26
*/
public static abstract class MyClickListener implements OnClickListener {
/**
* The onClick method of the base class
*/
@Override
public void onClick(View v) {
myOnClick((Integer) (), v);
}
public abstract void myOnClick(int position, View v);
}
}
Activity class:
package ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
public class MainActivity extends Activity implements OnItemClickListener {
// Simulate the data loaded in the listview private static final String[] CONTENTS = { "Beijing", "Shanghai", "Guangzhou", "Shenzhen", "Suzhou",
"Nanjing", "Wuhan", "Changsha", "Hangzhou" };
private List<String> contentList;
private ListView mListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
(savedInstanceState);
setContentView(.activity_main);
init();
}
private void init() {
mListView = (ListView) findViewById();
contentList = new ArrayList<String>();
for (int i = 0; i < ; i++) {
(CONTENTS[i]);
}
//Instantiate the ContentAdapter class and pass in the implementation class (new ContentAdapter(this, contentList, mListener));
(this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(, menu);
return true;
}
//Respond to item click event @Override
public void onItemClick(AdapterView<?> arg0, View v, int position, long id) {
(this, "The item of listview was clicked!, the clicked position is -->" + position,
Toast.LENGTH_SHORT).show();
}
/**
* Implementation class, respond to button click event
*/
private MyClickListener mListener = new MyClickListener() {
@Override
public void myOnClick(int position, View v) {
(
,
"The button inside the listview was clicked!, the position is -->" + position + ",The content is -->"
+ (position), Toast.LENGTH_SHORT)
.show();
}
};
}
The difference between the two methods is that when an abstract class is implemented in the Activity, it can only define a member variable to implement it, and cannot be directly implemented by the Activity, because Java does not support multiple inheritance. The interface can be implemented directly by Activity or by its member variables.
Original link: /u011895534/article/details/50439547
The above is all the content of this article. I hope it will be helpful to everyone's study and I hope everyone will support me more.