Preliminary Research on ListView

Preliminary Research on ListView

ListView may be one of the most commonly used controls in Android development. However, you still need to exercise carefully.

Create a simple ListView

1. Add the <ListView> label to the layout file (. xml ).

2. bind an adapter in MainActivity. java

　　

1 private String[] data = { "Apple", "Banana", "Orange", "Watermelon",2 "Pear", "Grape", "Pineapple", "Strawberry", "Cherry", "Mango" };3 4 5 ArrayAdapter<String> adapter = new ArrayAdapter<String>(6 MainActivity.this, android.R.layout.simple_list_item_1, data);7 ListView listView = (ListView) findViewById(R.id.list_view);8 listView.setAdapter(adapter);

You can see that the array content cannot be directly added to the ListView, so you must use an adapter.

In the adapter, I used String to display strings. In the future, more complex content, such as composite data, may be added.

ArrayAdapter has multiple constructor functions. The values here are called classes, ListView styles, and data sources.

 

　　In short, the data source is diverse. to display it on the ListView, we need to use an adapter.

 

Create a ListView with images

 

1. Create a class to save the composite type

2. Create 1 corresponding layout File

3. Create a dedicated adapter for 1 (extends ArrayAdapter)

4. Bind the adapter 1 package com. example. ran. listviewdemo to ListView in MainActivity;

 2  3 /** 4  * Created by Ran on 2016/3/21. 5  */ 6 public class MyData 7 {
 8     private  String name;　 9     private  int    imageId;　　10 11     public  MyData(String name,int imageId)12     {13         this.name = name;14         this.imageId = imageId;15     }16     public String getName() {17         return name;18     }19     public int getImageId() {20         return imageId;21     }22 }

ImageId is the resource ID of the corresponding image.

 

 1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3     android:layout_width="match_parent" 4     android:layout_height="match_parent"> 5  6     <ImageView 7         android:id="@+id/iimage" 8         android:layout_width="wrap_content" 9         android:layout_height="wrap_content" />10 11     <TextView12         android:id="@+id/iname"13         android:layout_width="wrap_content"14         android:layout_height="wrap_content"15         />16 </LinearLayout>

 1 package com.example.ran.listviewdemo; 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.ArrayAdapter; 8 import android.widget.ImageView; 9 import android.widget.TextView;10 11 import java.util.List;12 13 /**14  * Created by Ran on 2016/3/21.15  */16 public class MyDataAdapter extends ArrayAdapter<MyData> {17     private  int  resourceId;18 19     public  MyDataAdapter(Context context, int textViewResourceId,List<MyData> objects)20     {21         super(context, textViewResourceId, objects);22         resourceId = textViewResourceId;23     }24 25     @Override26     public  View getView(int position, View convertView, ViewGroup parent)27     {28         MyData myData = getItem(position);29         View view = LayoutInflater.from(getContext()).inflate(resourceId, null);30         ImageView iimage = (ImageView) view.findViewById(R.id.iimage);31         TextView iname = (TextView) view.findViewById(R.id.iname);32         iimage.setImageResource(myData.getImageId());33         iname.setText(myData.getName());34         return view;35     }36 }

1 package com. example. ran. listviewdemo; 2 3 import android. support. v7.app. appCompatActivity; 4 import android. OS. bundle; 5 import android. widget. listView; 6 7 import java. util. arrayList; 8 import java. util. list; 9 10 public class MainActivity extends AppCompatActivity {11 12 private List <MyData> dataList = new ArrayList <MyData> (); 13 14 @ Override15 protected void onCreate (Bundle savedInstanceState) {16 super. onCreate (savedInstanceState); 17 setContentView (R. layout. activity_main); 18 initData (); 19 MyDataAdapter adapter = new MyDataAdapter (MainActivity.20 this, R. layout. data_item, dataList); 21 ListView listView = (ListView) findViewById (R. id. list_view); 22 listView. setAdapter (adapter); 23} 24 25 private void initData () 26 {27 MyData t1 = new MyData ("You are so naughty, come, don't BB", R. mipmap. t1); 28 MyData t2 = new MyData ("You are naughty, come, don't BB", R. mipmap. t2); 29 MyData t3 = new MyData ("You are naughty, come, don't BB", R. mipmap. t3); 30 MyData t4 = new MyData ("You are so naughty, come, don't BB", R. mipmap. t4); 31 MyData t5 = new MyData ("You are so naughty, come, don't BB", R. mipmap. t5); 32 MyData t6 = new MyData ("You are so naughty, come, don't BB", R. mipmap. t6); 33 MyData t7 = new MyData ("You are so naughty, come, don't BB", R. mipmap. t7); 34 MyData t8 = new MyData ("You are so naughty, come, don't BB", R. mipmap. t8); 35 36 dataList. add (t1); 37 dataList. add (t2); 38 dataList. add (t3); 39 dataList. add (t4); 40 dataList. add (t5); 41 dataList. add (t6); 42 dataList. add (t7); 43 dataList. add (t8); 44 45 46} 47}