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[操作系统]BaseAdapterArrayAdapter在ListView中应用


一:BaseAdapter:共同实现的基类的适配器,是ArrayAdapter SimpleAdapter等的父类,

  一般用于比较复杂的ListView,扩展性强。

  详细信息可查看谷歌官方API: http://developer.android.com/reference/android/widget/BaseAdapter.html

  1:构造方法:BaseAdapter();

  2:公共方法:

  其中:ArrayAdapter(Context context, int resource, List<T> objects)较为常用;

  公共方法:

 

  2:布局代码为:activity_main.

 activity_main.

 1 <LinearLayout ="http://schemas.android.com/apk/res/android" 2   ="http://schemas.android.com/tools" 3   android:layout_width="match_parent" 4   android:layout_height="match_parent" 5   android:orientation="horizontal" 6   android:paddingBottom="@dimen/activity_vertical_margin" 7   android:paddingLeft="@dimen/activity_horizontal_margin" 8   android:paddingRight="@dimen/activity_horizontal_margin" 9   android:paddingTop="@dimen/activity_vertical_margin"10   tools:context=".MainActivity">11 12   <ListView13     android:id="@+id/listview_main"14     android:layout_width="wrap_content"15     android:layout_height="match_parent"16     android:layout_weight="1"></ListView>17 18   <ListView19     android:id="@+id/listText_item"20     android:layout_width="wrap_content"21     android:layout_height="match_parent"22     android:layout_weight="2">23 24 25   </ListView>26 </LinearLayout>

 

 imagelistview.

 1 <??> 2 <LinearLayout ="http://schemas.android.com/apk/res/android" 3   android:layout_width="match_parent" 4   android:layout_height="match_parent" 5   android:orientation="horizontal"> 6  7   <ImageView 8     android:id="@+id/iamge_item" 9     android:layout_width="60dp"10     android:layout_height="90dp"11     android:background="@drawable/image1"/>12   13   <LinearLayout14     android:layout_width="match_parent"15     android:layout_height="wrap_content"16     android:orientation="vertical">17 18     <TextView19       android:id="@+id/title_item"20       android:layout_width="match_parent"21       android:layout_height="20dp"22       android:text="标题" />23 24     <ScrollView25       android:layout_width="match_parent"26       android:layout_height="70dp">27 28       <TextView29         android:id="@+id/content_item"30         android:layout_width="match_parent"31         android:layout_height="match_parent"32         android:text="内容" />33     </ScrollView>34 35   </LinearLayout>36 </LinearLayout>

 

textlistview.

1 <??>2 <TextView ="http://schemas.android.com/apk/res/android"3   android:layout_width="match_parent"4   android:layout_height="30dp"5   android:orientation="vertical"6   android:scrollbars="vertical"></TextView>

 

 

  3:Activity代码为:

Msg对象类如下:

 1 package activity.cyq.listviewlearn; 2  3 /** 4  * Created by Android_007 on 2015/8/4. 5 */ 6 public class Msg { 7  8   public int iconId; 9   public String title;10   public String content;11 12   public Msg(int iconId, String title, String content) {13     this.iconId = iconId;14     this.title = title;15     this.content = content;16   }17 18   public int getIconId() {19     return iconId;20   }21 22   public void setIconId(int iconId) {23     this.iconId = iconId;24   }25 26   public String getTitle() {27     return title;28   }29 30   public void setTitle(String title) {31     this.title = title;32   }33 34   public String getContent() {35     return content;36   }37 38   public void setContent(String content) {39     this.content = content;40   }41 }

 

Maincity代码:

 1 package activity.cyq.listviewlearn; 2  3 import android.app.AlertDialog; 4 import android.content.DialogInterface; 5 import android.support.v7.app.AppCompatActivity; 6 import android.os.Bundle; 7 import android.view.LayoutInflater; 8 import android.view.View; 9 import android.view.ViewGroup; 10 import android.widget.AdapterView; 11 import android.widget.ArrayAdapter; 12 import android.widget.BaseAdapter; 13 import android.widget.ImageView; 14 import android.widget.LinearLayout; 15 import android.widget.ListView; 16 import android.widget.TextView; 17 import android.widget.Toast; 18 import java.util.ArrayList; 19  20 public class MainActivity extends AppCompatActivity { 21  22   private ListView leftView; 23   private ListView rightView; 24   private BaseAdapter adapter_image; /*左边含image的列表适配器*/ 25   private ArrayAdapter adapter_Text; /*右边含text的列表适配器*/ 26   private ArrayList<Msg> list_image = new ArrayList<>(); 27   private ArrayList<String> list_Text = new ArrayList<>(); 28  29   @Override 30   protected void onCreate(Bundle savedInstanceState) { 31     super.onCreate(savedInstanceState); 32     setContentView(R.layout.activity_main); 33     /**/ 34     leftView = (ListView) findViewById(R.id.listview_main); 35     rightView = (ListView) findViewById(R.id.listText_item); 36  37     /*为list_image添加数据*/ 38     list_image.add(new Msg(R.drawable.image1, "title 1", "context 1")); 39     list_image.add(new Msg(R.drawable.image2, "title 2", "context 2")); 40     list_image.add(new Msg(R.drawable.image3, "title 3", "context 3")); 41     list_image.add(new Msg(R.drawable.image4, "title 4", "context 4")); 42     /*为list_Text添加数据*/ 43     for (int i = 0; i < 12; i++) { 44       list_Text.add("这是ArrayAdapter适配器生成的第" + (i + 1) + "条数据"); 45     } 46  47     /*获得左侧列表的适配器 adapter_image 匿名类实例化 并实现四个方法 */ 48     adapter_image = new BaseAdapter() { 49       /*返回数据条数*/ 50       @Override 51       public int getCount() { 52         return list_image.size(); 53       } 54  55       /*返回每一项数据*/ 56       @Override 57       public Msg getItem(int position) { 58         return list_image.get(position); 59       } 60  61       /*返回该项数据的索引指*/ 62       @Override 63       public long getItemId(int position) { 64         return position; 65       } 66  67       /*构造列表项的视图,并返回*/ 68       @Override 69       public View getView(final int position, View convertView, ViewGroup parent) { 70       /* convertView 是回收的item视图 回收视图的再利用可减少每次在内存中新建一个视图 提高程序性能 */ 71         LinearLayout ll = null; 72         if (convertView == null) { 73           /*获得item视图*/ 74           ll = (LinearLayout) LayoutInflater.from(MainActivity.this).inflate(R.layout.imagelistview, null); 75         } 76         if (convertView != null) { 77           /*使用回收视图 */ 78           ll = (LinearLayout) convertView; 79         } 80  81         ImageView icon = (ImageView) ll.findViewById(R.id.iamge_item);/*注意ll这个View容器下获findViewById(R.id.**)*/ 82         TextView title_ = (TextView) ll.findViewById(R.id.title_item); 83         TextView content_ = (TextView) ll.findViewById(R.id.content_item); 84  85         icon.setImageResource(getItem(position).iconId); /*调用上面的geeItem方法 获得Msg对象 */ 86         title_.setText(getItem(position).title); 87         content_.setText(getItem(position).content); 88  89         /*item的点击事件*/ 90         ll.setOnClickListener(new View.OnClickListener() { 91           @Override 92           public void onClick(View v) { 93             Toast.makeText(MainActivity.this, "你点击了第" + (position + 1) + "个列表项。", Toast.LENGTH_SHORT).show(); 94  95           } 96         }); 97         /*item子元素的点击事件*/ 98         icon.setOnClickListener(new View.OnClickListener() { 99           @Override100           public void onClick(View v) {101             Toast.makeText(MainActivity.this, "你点击了第" + (position + 1) + "张图片。", Toast.LENGTH_SHORT).show();102           }103         });104 105         /*item长按事件 实现删除该item*/106         ll.setOnLongClickListener(new View.OnLongClickListener() {107           @Override108           public boolean onLongClick(View v) {109             new AlertDialog.Builder(MainActivity.this)110                 .setTitle("警告!")111                 .setMessage("确认删除该项?")112                 .setIcon(R.drawable.delete)113                 .setPositiveButton("是", new DialogInterface.OnClickListener() {114                   @Override115                   public void onClick(DialogInterface dialog, int which) {116                    /*如何删除该项数据 ???*/117                     list_image.remove(position);118                     leftView.setAdapter(adapter_image);119                   }120                 })121                 .setNegativeButton("否", null)122                 .show();123             return true;/* true:接受系统自定义的反馈,比如震动,音效等 false:无反馈 */124           }125         });126         return ll;127       }128     };129 130     /*右侧的ArrayAdapter适配器 通过匿名类实现。也可以通过子类继承ArrayAdapter */131     //adapter_Text = new ArrayAdapter(MainActivity.this, android.R.layout.simple_list_item_1, list_Text);/*这列代码,使用的是android系统自带的资源*/132     adapter_Text = new ArrayAdapter(MainActivity.this, R.layout.textlistveiw, list_Text); /* 使用自定义的资源文件 该文件标签只能<TextView/> */133     /*item的点击事件*/134     rightView.setOnItemClickListener(new AdapterView.OnItemClickListener() {135       @Override136       public void onItemClick(AdapterView<?> parent, View view, int position, long id) {137         Toast.makeText(MainActivity.this, "你点击了第" + (position + 1) + "个Item项", Toast.LENGTH_SHORT).show();138       }139     });140     /*iitem长按删除改项的事件*/141     rightView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {142       @Override143       public boolean onItemLongClick(AdapterView<?> parent, final View view, final int position, long id) {144         new AlertDialog.Builder(MainActivity.this)145             .setTitle("警告")146             .setMessage("是否删除该项?")147             .setIcon(R.drawable.delete)148             .setPositiveButton("是", new DialogInterface.OnClickListener() {149               @Override150               public void onClick(DialogInterface dialog, int which) {151                 /* adapter_Text.remove(position); 不能这样使用152                   查看谷歌的Guide API得知 ArrayAdapter.remove(object)153                   这个方法的作用的删除数组中指定的对象 显然我们删除索引是行不通的154                   所以我们需要删除ArrayAdapter中的object对象,也就是list_Text[position]155                   adapter_Text.remove(list_Text.get(position));156                   rightView.setAdapter(adapter_Text);157                  */158                 list_Text.remove(position);159                 rightView.setAdapter(adapter_Text);160               }161             })162             .setNegativeButton("否", null)163             .show();164         return true;165       }166     });167 168     /*为试图添加适配器*/169     leftView.setAdapter(adapter_image);170     rightView.setAdapter(adapter_Text);171   }172 173 }