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  • ListView移动和动态添加数据

    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 }
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  • 原文地址:https://www.cnblogs.com/zhengzhe/p/7821047.html
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