ListView移动和动态添加数据

Posted 2020-10-14 郑哲

效果图如下：

viewholder_item.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:orientation="vertical"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent">
 6 
 7 
 8 
 9     <ImageView
10         android:id="@+id/iv"
11         android:layout_width="wrap_content"
12         android:layout_height="wrap_content" />
13 
14     <TextView
15         android:id="@+id/tv"
16         android:layout_width="wrap_content"
17         android:layout_height="wrap_content" />
18 </LinearLayout>

 

ViewHolderAdapter.java

 1 package sowell.oracle.com.listviewholder;
 2 
 3 import android.content.Context;
 4 import android.view.LayoutInflater;
 5 import android.view.View;
 6 import android.view.ViewGroup;
 7 import android.widget.BaseAdapter;
 8 import android.widget.ImageView;
 9 import android.widget.TextView;
10 
11 import java.util.List;
12 
13 /**
14  * Created by 94965 on 2017/11/11.
15  */
16 
17 public class ViewHolderAdapter extends BaseAdapter {
18 
19     private List<String> mData;             //储存数据
20     private LayoutInflater mInflater;      //实例化布局
21 
22     public ViewHolderAdapter(Context context,List<String> data){
23         super();
24         this.mData=data;
25         mInflater=LayoutInflater.from(context);
26     }
27 
28 
29 
30     @Override
31     public int getCount() {
32         return mData.size();
33     }
34 
35     @Override
36     public Object getItem(int position) {
37         return mData.get(position);
38     }
39 
40     @Override
41     public long getItemId(int position) {
42         return position;
43     }
44 
45     @Override
46     public View getView(int position, View convertView, ViewGroup parent) {
47         ViewHolder holder=null;
48         //判断是否缓存
49         if(convertView==null){
50             holder=new ViewHolder();
51             //通过LayoutInflater实例化布局
52             convertView=mInflater.inflate(R.layout.viewholder_item,null);
53             holder.img=(ImageView)convertView.findViewById(R.id.iv);
54             holder.title=(TextView)convertView.findViewById(R.id.tv);
55             convertView.setTag(holder);
56         }else {
57             //通过tag找到缓存‘的布局
58             holder=(ViewHolder)convertView.getTag();
59         }
60 
61         //设置布局中控件要显示的视图
62         holder.img.setBackgroundResource(R.mipmap.ic_launcher);
63         holder.title.setText(mData.get(position));
64         return convertView;
65     }
66 
67 
68 
69     public final class ViewHolder{
70         public ImageView img;
71         public TextView title;
72     }
73 }

 

activity_main.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="wrap_content"
 6     android:orientation="vertical"
 7     tools:context="sowell.oracle.com.listviewholder.MainActivity">
 8 
 9 
10 
11 
12     <ListView
13         android:id="@+id/lv"
14         android:layout_width="match_parent"
15         android:layout_height="450dp"
16         android:divider="@android:color/darker_gray"
17         android:dividerHeight="1dp"
18         >
19     </ListView>
20 
21 
22 
23 
24     <Button
25         android:id="@+id/btn"
26         android:layout_width="match_parent"
27         android:layout_height="wrap_content"
28         android:text="add" />
29 
30 
31     <LinearLayout
32         android:layout_width="match_parent"
33         android:layout_height="wrap_content"
34         android:orientation="horizontal"
35         >
36         <EditText
37             android:id="@+id/et"
38             android:layout_weight="1"
39             android:layout_width="wrap_content"
40             android:layout_height="wrap_content" />
41         <Button
42             android:id="@+id/btn1"
43             android:layout_weight="1"
44             android:onClick="moveto"
45             android:text="移动"
46             android:layout_width="wrap_content"
47             android:layout_height="wrap_content" />
48     </LinearLayout>
49 
50 
51 </LinearLayout>

 

MainActivity.java

 1 package sowell.oracle.com.listviewholder;
 2 
 3 import android.support.v7.app.AppCompatActivity;
 4 import android.os.Bundle;
 5 import android.util.Log;
 6 import android.view.View;
 7 import android.view.WindowManager;
 8 import android.widget.Button;
 9 import android.widget.EditText;
10 import android.widget.ListView;
11 import android.widget.Toast;
12 
13 import java.util.ArrayList;
14 import java.util.List;
15 
16 public class MainActivity extends AppCompatActivity {
17 
18     public ListView listView;
19     public ViewHolderAdapter adapter;
20     public List<String> list;
21     public String string;
22     public Button bt;
23     public Button move;
24     private EditText et;
25     public void init(){
26 
27         move=(Button)findViewById(R.id.btn1);
28         et=(EditText)findViewById(R.id.et);
29         bt=(Button)findViewById(R.id.btn);
30         bt.setOnClickListener(new View.OnClickListener() {
31             @Override
32             public void onClick(View v) {
33                 add();
34             }
35         });
36         list=new ArrayList<String>();
37         for(int i=0;i<=20;i++)
38         {
39             string=""+i;
40             list.add(string);
41         }
42         adapter=new ViewHolderAdapter(this,list);
43         listView=(ListView)findViewById(R.id.lv);
44         listView.setAdapter(adapter);
45 
46     }
47 
48 
49     @Override
50     protected void onCreate(Bundle savedInstanceState) {
51         super.onCreate(savedInstanceState);
52         getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN); //防止被输入框被遮盖
53         setContentView(R.layout.activity_main);
54         init();
55     }
56 
57     public void moveto(View view){
58         int position=Integer.parseInt(et.getText().toString());
59         if(position>=0&&position<=list.size()-1)
60             listView.smoothScrollByOffset(position);//平滑移动到布局第一个元素为position
61             //listView.smoothScrollToPosition(position);
62     }
63 
64     public void add(){
65         list.add("new");
66         adapter.notifyDataSetChanged();     //动态添加listview中的数据
67         //listView.setSelection(list.size()-1);//瞬间移动
68         listView.smoothScrollToPosition(list.size()-1);//平滑移动到布局中有该位置
69 
70     }
71 }