最近交流群里面有人问到一个问题：如何在Activity中响应ListView内部按钮的点击事件，不要在Adapter中响应？
对于这个问题，我最初给他的解答是，在Adapter中定义一个回调接口，在Activity中实现该接口，从而实现对点击事件的响应。
下班后思考了一下，觉得有两种方式都能比较好的实现：使用接口回调和使用抽象类回调。
正好可以复习一下接口和抽象类的区别，于是写了两个Demo：
1.使用接口回调：
Adapter类
1 package com.ivan.adapter; 2 3 import java.util.List; 4 5 import android.content.Context; 6 import android.util.Log; 7 import android.view.LayoutInflater; 8 import android.view.View; 9 import android.view.View.OnClickListener;10 import android.view.ViewGroup;11 import android.widget.BaseAdapter;12 import android.widget.Button;13 import android.widget.TextView;14 15 import com.ivan.listvieweventcallback.R;16 17 public class ContentAdapter extends BaseAdapter implements OnClickListener {18 19 private static final String TAG = "ContentAdapter";20 private List mContentList;21 private LayoutInflater mInflater;22 private Callback mCallback;23 24 /**25 * 自定义接口，用于回调按钮点击事件到Activity26 * @author Ivan Xu27 * 2014-11-2628 */29 public interface Callback {30 public void click(View v);31 }32 33 public ContentAdapter(Context context, List contentList,34 Callback callback) {35 mContentList = contentList;36 mInflater = LayoutInflater.from(context);37 mCallback = callback;38 }39 40 @Override41 public int getCount() {42 Log.i(TAG, "getCount");43 return mContentList.size();44 }45 46 @Override47 public Object getItem(int position) {48 Log.i(TAG, "getItem");49 return mContentList.get(position);50 }51 52 @Override53 public long getItemId(int position) {54 Log.i(TAG, "getItemId");55 return position;56 }57 58 @Override59 public View getView(int position, View convertView, ViewGroup parent) {60 Log.i(TAG, "getView");61 ViewHolder holder = null;62 if (convertView == null) {63 convertView = mInflater.inflate(R.layout.list_item, null);64 holder = new ViewHolder();65 holder.textView = (TextView) convertView66 .findViewById(R.id.textView1);67 holder.button = (Button) convertView.findViewById(R.id.button1);68 convertView.setTag(holder);69 } else {70 holder = (ViewHolder) convertView.getTag();71 }72 holder.textView.setText(mContentList.get(position));73 74 75 holder.button.setOnClickListener(this);76 holder.button.setTag(position);77 return convertView;78 }79 80 public class ViewHolder {81 public TextView textView;82 public Button button;83 }84 85 //响应按钮点击事件,调用子定义接口，并传入View86 @Override87 public void onClick(View v) {88 mCallback.click(v);89 }90 } Activity类：
1 package com.ivan.listvieweventdemo; 2 3 import java.util.ArrayList; 4 import java.util.List; 5 6 import android.app.Activity; 7 import android.os.Bundle; 8 import android.view.Menu; 9 import android.view.View;10 import android.widget.AdapterView;11 import android.widget.AdapterView.OnItemClickListener;12 import android.widget.ListView;13 import android.widget.Toast;14 15 import com.ivan.adapter.ContentAdapter;16 import com.ivan.adapter.ContentAdapter.Callback;17 import com.ivan.listvieweventcallback.R;18 //MainActivity需要实现自定义接口19 public class MainActivity extends Activity implements OnItemClickListener,20 Callback {21 22 // 模拟listview中加载的数据23 private static final String[] CONTENTS = { "北京", "上海", "广州", "深圳", "苏州",24 "南京", "武汉", "长沙", "杭州" };25 private List contentList;26 private ListView mListView;27 28 @Override29 protected void onCreate(Bundle savedInstanceState) {30 super.onCreate(savedInstanceState);31 setContentView(R.layout.activity_main);32 33 init();34 }35 36 private void init() {37 mListView = (ListView) findViewById(R.id.listview);38 contentList = new ArrayList ();39 for (int i = 0; i < CONTENTS.length; i++) {40 contentList.add(CONTENTS[i]);41 }42 //43 mListView.setAdapter(new ContentAdapter(this, contentList, this));44 mListView.setOnItemClickListener(this);45 }46 47 @Override48 public boolean onCreateOptionsMenu(Menu menu) {49 getMenuInflater().inflate(R.menu.main, menu);50 return true;51 }52 53 /**54 * 响应ListView中item的点击事件55 */56 @Override57 public void onItemClick(AdapterView arg0, View v, int position, long id) {58 Toast.makeText(this, "listview的item被点击了！，点击的位置是-->" + position,59 Toast.LENGTH_SHORT).show();60 }61 62 /**63 * 接口方法，响应ListView按钮点击事件64 */65 @Override66 public void click(View v) {67 Toast.makeText(68 MainActivity.this,69 "listview的内部的按钮被点击了！，位置是-->" + (Integer) v.getTag() + ",内容是-->"70 + contentList.get((Integer) v.getTag()),71 Toast.LENGTH_SHORT).show();72 }73 } 2.使用抽象类回调
Adapter类：
1 package com.ivan.adapter; 2 3 import java.util.List; 4 5 import android.content.Context; 6 import android.util.Log; 7 import android.view.LayoutInflater; 8 import android.view.View; 9 import android.view.View.OnClickListener;10 import android.view.ViewGroup;11 import android.widget.BaseAdapter;12 import android.widget.Button;13 import android.widget.TextView;14 15 import com.ivan.listvieweventabstract.R;16 17 public class ContentAdapter extends BaseAdapter {18 19 private static final String TAG = "ContentAdapter";20 private List mContentList;21 private LayoutInflater mInflater;22 private MyClickListener mListener;23 24 public ContentAdapter(Context context, List contentList,25 MyClickListener listener) {26 mContentList = contentList;27 mInflater = LayoutInflater.from(context);28 mListener = listener;29 }30 31 @Override32 public int getCount() {33 Log.i(TAG, "getCount");34 return mContentList.size();35 }36 37 @Override38 public Object getItem(int position) {39 Log.i(TAG, "getItem");40 return mContentList.get(position);41 }42 43 @Override44 public long getItemId(int position) {45 Log.i(TAG, "getItemId");46 return position;47 }48 49 @Override50 public View getView(int position, View convertView, ViewGroup parent) {51 Log.i(TAG, "getView");52 ViewHolder holder = null;53 if (convertView == null) {54 convertView = mInflater.inflate(R.layout.list_item, null);55 holder = new ViewHolder();56 holder.textView = (TextView) convertView57 .findViewById(R.id.textView1);58 holder.button = (Button) convertView.findViewById(R.id.button1);59 convertView.setTag(holder);60 } else {61 holder = (ViewHolder) convertView.getTag();62 }63 holder.textView.setText(mContentList.get(position));64 holder.button.setOnClickListener(mListener);65 holder.button.setTag(position);66 return convertView;67 }68 69 public class ViewHolder {70 public TextView textView;71 public Button button;72 }73 74 /**75 * 用于回调的抽象类76 * @author Ivan Xu77 * 2014-11-2678 */79 public static abstract class MyClickListener implements OnClickListener {80 /**81 * 基类的onClick方法82 */83 @Override84 public void onClick(View v) {85 myOnClick((Integer) v.getTag(), v);86 }87 public abstract void myOnClick(int position, View v);88 }89 } Activity类：
1 package com.ivan.listvieweventdemo; 2 3 import java.util.ArrayList; 4 import java.util.List; 5 6 import android.app.Activity; 7 import android.os.Bundle; 8 import android.view.Menu; 9 import android.view.View;10 import android.widget.AdapterView;11 import android.widget.AdapterView.OnItemClickListener;12 import android.widget.ListView;13 import android.widget.Toast;14 15 import com.ivan.adapter.ContentAdapter;16 import com.ivan.adapter.ContentAdapter.MyClickListener;17 import com.ivan.listvieweventabstract.R;18 19 public class MainActivity extends Activity implements OnItemClickListener {20 21 // 模拟listview中加载的数据22 private static final String[] CONTENTS = { "北京", "上海", "广州", "深圳", "苏州",23 "南京", "武汉", "长沙", "杭州" };24 private List contentList;25 private ListView mListView;26 27 @Override28 protected void onCreate(Bundle savedInstanceState) {29 super.onCreate(savedInstanceState);30 setContentView(R.layout.activity_main);31 32 init();33 }34 35 private void init() {36 mListView = (ListView) findViewById(R.id.listview);37 contentList = new ArrayList ();38 for (int i = 0; i < CONTENTS.length; i++) {39 contentList.add(CONTENTS[i]);40 }41 //实例化ContentAdapter类，并传入实现类42 mListView.setAdapter(new ContentAdapter(this, contentList, mListener));43 44 mListView.setOnItemClickListener(this);45 }46 47 @Override48 public boolean onCreateOptionsMenu(Menu menu) {49 getMenuInflater().inflate(R.menu.main, menu);50 return true;51 }52 53 //响应item点击事件54 @Override55 public void onItemClick(AdapterView arg0, View v, int position, long id) {56 Toast.makeText(this, "listview的item被点击了！，点击的位置是-->" + position,57 Toast.LENGTH_SHORT).show();58 }59 60 /**61 * 实现类，响应按钮点击事件62 */63 private MyClickListener mListener = new MyClickListener() {64 @Override65 public void myOnClick(int position, View v) {66 Toast.makeText(67 MainActivity.this,68 "listview的内部的按钮被点击了！，位置是-->" + position + ",内容是-->"69 + contentList.get(position), Toast.LENGTH_SHORT)70 .show();71 }72 };73 }
以下是布局文件
110 11 15 16 17
两种方式的区别在于，抽象类在Activity中实现的时候，只能定义一个成员变量来实现，不能由Activity直接实现，因为Java不支持多继承。而接口既可以由Activity直接实现，也可以由其成员变量来实现。
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