列表视图ListView

依然是一个listView的Java文件

 1 public class ListViewActivity extends Activity {
 2     private ListView lv1;
 3     @Override
 4     protected void onCreate(@Nullable Bundle savedInstenceState) {
 5
 6         super.onCreate(savedInstenceState);
 7         setContentView(R.layout.activity_listview);
 8         lv1=findViewById(R.id.lv_1);
 9         lv1.setAdapter(new MylistAdapter(ListViewActivity.this));
10         lv1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
11             @Override
12             public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
13                 Toast.makeText(ListViewActivity.this, "点击pos:"+i, Toast.LENGTH_SHORT).show();
14             }
15         });
16         lv1.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
17             @Override
18             public boolean onItemLongClick(AdapterView<?> adapterView, View view, int i, long l) {
19                 Toast.makeText(ListViewActivity.this, "长按pos:"+i, Toast.LENGTH_SHORT).show();
20                 return true;//这里如果返回false的话，处理完长按事件后还会处理点击事件，也就是说会弹出两个提示框，为了让他只显示一个对话框改为true
21             }
22         });
23     }
24 }

对应的activity_listview.xml文件

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="match_parent"
 3     android:layout_height="match_parent">
 4
 5     <ListView
 6         android:id="@+id/lv_1"
 7         android:layout_width="match_parent"
 8         android:layout_height="wrap_content"
 9         android:listSelector="@drawable/list_item"/>
10         <!-- 这里listSelector设置的是点击样式，效果-->
11
12 </LinearLayout>

其中设置的点击效果xml文件为

1 <selector xmlns:android="http://schemas.android.com/apk/res/android">
2     <item android:state_pressed="true" android:drawable="@color/purple_200"/>
3     <item android:drawable="@color/touming"/>
4 </selector>

这里面state_pressed和state_checked是不一样的，checked是选中的意思，pressed是按压时候的效果，注意区分。

然后layout_list_item.xml文件是设置list中每一个元素的样式结构的文件

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="match_parent"
 3     android:layout_height="match_parent"
 4     android:orientation="horizontal"
 5     android:padding="10dp">
 6     <ImageView
 7         android:id="@+id/imv"
 8         android:layout_width="100dp"
 9         android:layout_height="100dp"
10         android:scaleType="centerCrop"
11         android:background="#000"/>
12     <LinearLayout
13         android:layout_width="match_parent"
14         android:layout_height="wrap_content"
15         android:orientation="vertical"
16         android:paddingLeft="10dp">
17         <TextView
18             android:id="@+id/tv_title"
19             android:layout_width="wrap_content"
20             android:layout_height="wrap_content"
21             android:text="你好你好"
22             android:textColor="@color/black"
23             android:textSize="20sp"/>
24         <TextView
25             android:id="@+id/tv_time"
26             android:layout_width="wrap_content"
27             android:layout_height="wrap_content"
28             android:text="2022-01-28"
29             android:textColor="@color/greydrak"
30             android:paddingTop="10dp"
31             android:textSize="17sp"/>
32         <TextView
33             android:id="@+id/tv_content"
34             android:layout_width="wrap_content"
35             android:layout_height="wrap_content"
36             android:text="你好，我是内容"
37             android:textColor="@color/greydrak"
38             android:paddingTop="10dp"
39             android:textSize="17sp"/>
40     </LinearLayout>
41 </LinearLayout>

然后建立MyListAdapter的Java文件来定义列表中每个元素的具体结构的值：

 1 public class MylistAdapter extends BaseAdapter {
 2     private Context context;
 3     private LayoutInflater layoutInflater;
 4     public MylistAdapter(Context context){
 5         this.context=context;
 6         layoutInflater=LayoutInflater.from(context);
 7     }
 8     @Override
 9     public int getCount() {
10         return 10;
11     }//列表长度
12
13     @Override
14     public Object getItem(int i) {
15         return null;
16     }//不怎么用
17
18     @Override
19     public long getItemId(int i) {
20         return 0;
21     }//不怎么用
22
23     static class ViewHolder{
24         public ImageView imageview;
25         public TextView tvTitle,tvTime,tvContent;
26     }
27
28     @Override
29     public View getView(int i, View view, ViewGroup viewGroup) {
30         ViewHolder holder=null;
31         if(view==null){
32             view=layoutInflater.inflate(R.layout.layout_list_item,null);
33             holder=new ViewHolder();
34             holder.imageview=view.findViewById(R.id.imv);
35             holder.tvTitle=view.findViewById(R.id.tv_title);
36             holder.tvContent=view.findViewById(R.id.tv_content);
37             holder.tvTime=view.findViewById(R.id.tv_time);
38             view.setTag(holder);
39         }else{
40             holder= (ViewHolder) view.getTag();
41         }
42         //给控件赋值
43         holder.tvTitle.setText("我是大标题");
44         holder.tvTime.setText("2066-06-6");
45         holder.tvContent.setText("说点啥呢啥呢");
46         Glide.with(context).load("https://www.baidu.com/img/PCtm_d9c8750bed0b3c7d089fa7d55720d6cf.png").into(holder.imageview);
47         return view;
48     }
49 }