轉載:http://www.cnblogs.com/ivan-xu/p/4124967.htmlhtml
最近交流羣裏面有人問到一個問題:如何在Activity中響應ListView內部按鈕的點擊事件,不要在Adapter中響應?java
對於這個問題,我最初給他的解答是,在Adapter中定義一個回調接口,在Activity中實現該接口,從而實現對點擊事件的響應。android
下班後思考了一下,以爲有兩種方式都能比較好的實現:使用接口回調和使用抽象類回調。app
正好能夠複習一下接口和抽象類的區別,因而寫了兩個Demo:ide
1.使用接口回調:佈局
Adapter類post
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<String> mContentList;
21 private LayoutInflater mInflater;
22 private Callback mCallback; //注:全部listview的item共用同一個
23
24 /**
25 * 自定義接口,用於回調按鈕點擊事件到Activity
26 * @author Ivan Xu
27 * 2014-11-26
28 */
29 public interface Callback {
30 public void click(View v);
31 }
32
33 public ContentAdapter(Context context, List<String> contentList,
34 Callback callback) {
35 mContentList = contentList;
36 mInflater = LayoutInflater.from(context);
37 mCallback = callback;
38 }
39
40 @Override
41 public int getCount() {
42 Log.i(TAG, "getCount");
43 return mContentList.size();
44 }
45
46 @Override
47 public Object getItem(int position) {
48 Log.i(TAG, "getItem");
49 return mContentList.get(position);
50 }
51
52 @Override
53 public long getItemId(int position) {
54 Log.i(TAG, "getItemId");
55 return position;
56 }
57
58 @Override
59 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) convertView
66 .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 //響應按鈕點擊事件,調用子定義接口,並傳入View
86 @Override
87 public void onClick(View v) {
88 mCallback.click(v);
89 }
90 }
Activity類:this
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須要實現自定義接口 19 public class MainActivity extends Activity implements OnItemClickListener, 20 Callback { 21 22 // 模擬listview中加載的數據 23 private static final String[] CONTENTS = { "北京", "上海", "廣州", "深圳", "蘇州", 24 "南京", "武漢", "長沙", "杭州" }; 25 private List<String> contentList; 26 private ListView mListView; 27 28 @Override 29 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<String>(); 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 @Override 48 public boolean onCreateOptionsMenu(Menu menu) { 49 getMenuInflater().inflate(R.menu.main, menu); 50 return true; 51 } 52 53 /** 54 * 響應ListView中item的點擊事件 55 */ 56 @Override 57 public void onItemClick(AdapterView<?> arg0, View v, int position, long id) { 58 Toast.makeText(this, "listview的item被點擊了!,點擊的位置是-->" + position, 59 Toast.LENGTH_SHORT).show(); 60 } 61 62 /** 63 * 接口方法,響應ListView按鈕點擊事件 64 */ 65 @Override 66 public void click(View v) { 67 Toast.makeText( 68 MainActivity.this, 69 "listview的內部的按鈕被點擊了!,位置是-->" + (Integer) v.getTag() + ",內容是-->" 70 + contentList.get((Integer) v.getTag()), 71 Toast.LENGTH_SHORT).show(); 72 } 73 }
2.使用抽象類回調url
Adapter類:spa
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<String> mContentList; 21 private LayoutInflater mInflater; 22 private MyClickListener mListener; //注:全部listview的item都共用同一個listener對象!!! 23 24 public ContentAdapter(Context context, List<String> contentList, 25 MyClickListener listener) { 26 mContentList = contentList; 27 mInflater = LayoutInflater.from(context); 28 mListener = listener; 29 } 30 31 @Override 32 public int getCount() { 33 Log.i(TAG, "getCount"); 34 return mContentList.size(); 35 } 36 37 @Override 38 public Object getItem(int position) { 39 Log.i(TAG, "getItem"); 40 return mContentList.get(position); 41 } 42 43 @Override 44 public long getItemId(int position) { 45 Log.i(TAG, "getItemId"); 46 return position; 47 } 48 49 @Override 50 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) convertView 57 .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); //注:這樣能使全部listview的item都共用同一個listener,而不用爲每一個item都設置各自的listener!!! 66 return convertView; 67 } 68 69 public class ViewHolder { 70 public TextView textView; 71 public Button button; 72 } 73 74 /** 75 * 用於回調的抽象類 76 * @author Ivan Xu 77 * 2014-11-26 78 */ 79 public static abstract class MyClickListener implements OnClickListener { 80 /** 81 * 基類的onClick方法 82 */ 83 @Override 84 public void onClick(View v) { 85 myOnClick((Integer) v.getTag(), v); 86 } 87 public abstract void myOnClick(int position, View v); 88 } 89 }
Activity類:
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 // 模擬listview中加載的數據 22 private static final String[] CONTENTS = { "北京", "上海", "廣州", "深圳", "蘇州", 23 "南京", "武漢", "長沙", "杭州" }; 24 private List<String> contentList; 25 private ListView mListView; 26 27 @Override 28 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<String>(); 38 for (int i = 0; i < CONTENTS.length; i++) { 39 contentList.add(CONTENTS[i]); 40 } 41 //實例化ContentAdapter類,並傳入實現類 42 mListView.setAdapter(new ContentAdapter(this, contentList, mListener)); 43 44 mListView.setOnItemClickListener(this); 45 } 46 47 @Override 48 public boolean onCreateOptionsMenu(Menu menu) { 49 getMenuInflater().inflate(R.menu.main, menu); 50 return true; 51 } 52 53 //響應item點擊事件 54 @Override 55 public void onItemClick(AdapterView<?> arg0, View v, int position, long id) { 56 Toast.makeText(this, "listview的item被點擊了!,點擊的位置是-->" + position, 57 Toast.LENGTH_SHORT).show(); 58 } 59 60 /** 61 * 實現類,響應按鈕點擊事件 62 */ 63 private MyClickListener mListener = new MyClickListener() { 64 @Override 65 public void myOnClick(int position, View v) { 66 Toast.makeText( 67 MainActivity.this, 68 "listview的內部的按鈕被點擊了!,位置是-->" + position + ",內容是-->" 69 + contentList.get(position), Toast.LENGTH_SHORT) 70 .show(); 71 } 72 }; 73 }
如下是佈局文件
1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 xmlns:tools="http://schemas.android.com/tools" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 android:paddingBottom="@dimen/activity_vertical_margin" 6 android:paddingLeft="@dimen/activity_horizontal_margin" 7 android:paddingRight="@dimen/activity_horizontal_margin" 8 android:paddingTop="@dimen/activity_vertical_margin" 9 tools:context=".MainActivity" > 10 11 <ListView 12 android:id="@+id/listview" 13 android:layout_width="match_parent" 14 android:layout_height="match_parent" > 15 </ListView> 16 17 </RelativeLayout>
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:descendantFocusability="blocksDescendants" android:orientation="vertical" > <TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="content" android:textColor="#ff0000" android:textSize="20sp" /> <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:focusable="false" android:text="Button" android:textColor="#ff0000" android:textSize="20sp" /> </LinearLayout>
總結:兩種方法都是經過在Activity中實現抽象方法來實現點擊時的具體操做,區別在於這個抽象方法是屬於接口的成員仍是屬於抽象類的成員。