List controls for Android Development

I. Basic Knowledge:

ListView is a commonly used control. Each Item in the ListView can be a string or a combination control. First, let's talk about the implementation of ListView:

1. Prepare the data to be displayed in ListView;

2. Use a one-dimensional or multi-dimensional dynamic array to save data;

3. Build an adapter. In simple terms, the adapter is an Item array, and the number of items is generated when the dynamic array has many elements;

4. Add the adapter to the ListView and display it.

Ii. Code display:

1. "Activity_10srcyanactivity_10MainActivity.java"

[Java]

Package yan. activity_10;

 

Import java. util. ArrayList;

Import java. util. HashMap;

 

Import android. OS. Bundle;

Import android. view. View;

Import android. widget. ListView;

Import android. widget. SimpleAdapter;

Import android. app. ListActivity;

 

Public class MainActivity extends ListActivity {

Private final String raw_user_name = "user_name ";

Private final String raw_user_id = "user_id ";

Private final String raw_user_ip = "user_ip ";

Private String user_name_array [] = {"zhangsan", "lisi", "wangwu "};

Private String user_ip_array [] = {

"192.168.1.115 ",

"192.168.1.116 ",

"192.168.1.117 "};

@ Override

Protected void onCreate (Bundle savedInstanceState ){

Super. onCreate (savedInstanceState );

SetContentView (R. layout. main );

// Generate a dynamic array and input data

ArrayList <HashMap <String, String> mylistArray = new ArrayList <HashMap <String, String> ();

For (int I = 0; I <30; ++ I)

{

HashMap <String, String> map = new HashMap <String, String> ();

System. out. println ("HAH:" + I % 3 );

Map. put (raw_user_name, user_name_array [I % 3]);

Map. put (raw_user_id, I + 1 + "");

Map. put (raw_user_ip, user_ip_array [I % 3]);

MylistArray. add (map );

}

// Generate the adapter, array --> ListItem

SimpleAdapter mSchedule = new SimpleAdapter (

This,

MylistArray, // Data Source

R. layout. my_listview, // XML Implementation of ListItem

New String [] {raw_user_name, raw_user_id, raw_user_ip}, // subitem corresponding to the dynamic array and ListItem

New int [] {R. id. user_name, R. id. user_id, R. id. user_ip} // two TextView IDs in the XML file of ListItem

);

SetListAdapter (mSchedule );

}

 

@ Override

Protected void onListItemClick (ListView l, View v, int position, long id ){

// TODO Auto-generated method stub

Super. onListItemClick (l, v, position, id );

System. out. println ("id ----------------" + id );

System. out. println ("position ----------------" + position );

}

}

Package yan. activity_10;

Import java. util. ArrayList;

Import java. util. HashMap;

Import android. OS. Bundle;

Import android. view. View;

Import android. widget. ListView;

Import android. widget. SimpleAdapter;

Import android. app. ListActivity;

Public class MainActivity extends ListActivity {

Private final String raw_user_name = "user_name ";

Private final String raw_user_id = "user_id ";

Private final String raw_user_ip = "user_ip ";

 

Private String user_name_array [] = {"zhangsan", "lisi", "wangwu "};

Private String user_ip_array [] = {

"192.168.1.115 ",

"192.168.1.116 ",

"192.168.1.117 "};

 

@ Override

Protected void onCreate (Bundle savedInstanceState ){

Super. onCreate (savedInstanceState );

SetContentView (R. layout. main );

// Generate a dynamic array and input data

ArrayList <HashMap <String, String> mylistArray = new ArrayList <HashMap <String, String> ();

For (int I = 0; I <30; ++ I)

{

HashMap <String, String> map = new HashMap <String, String> ();

System. out. println ("HAH:" + I % 3 );

Map. put (raw_user_name, user_name_array [I % 3]);

Map. put (raw_user_id, I + 1 + "");

Map. put (raw_user_ip, user_ip_array [I % 3]);

MylistArray. add (map );

}

// Generate the adapter, array --> ListItem

SimpleAdapter mSchedule = new SimpleAdapter (

This,

MylistArray, // Data Source

R. layout. my_listview, // XML Implementation of ListItem

New String [] {raw_user_name, raw_user_id, raw_user_ip}, // subitem corresponding to the dynamic array and ListItem

New int [] {R. id. user_name, R. id. user_id, R. id. user_ip} // two TextView IDs in the XML file of ListItem

);

SetListAdapter (mSchedule );

}

@ Override

Protected void onListItemClick (ListView l, View v, int position, long id ){

// TODO Auto-generated method stub

Super. onListItemClick (l, v, position, id );

System. out. println ("id ----------------" + id );

System. out. println ("position ----------------" + position );

}

 

 

}

 

2. "Activity_10reslayoutmain.xml"

[Html]

<? Xml version = "1.0" encoding = "UTF-8"?>

<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"

Android: orientation = "vertical"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

>

<ListView

Android: id = "@ + id/android: list"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: drawselectid Top = "false"

Android: scrollbars = "vertical"

/>

</LinearLayout>

<? Xml version = "1.0" encoding = "UTF-8"?>

<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"

Android: orientation = "vertical"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

>

<ListView

Android: id = "@ + id/android: list"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: drawselectid Top = "false"

Android: scrollbars = "vertical"

/>

</LinearLayout>

3. "Activity_10reslayoutmy_listview.xml" my_listview.xml is used to design the items of ListView:

[Html]

<? Xml version = "1.0" encoding = "UTF-8"?>

<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"

Android: layout_width = "fill_parent"

Android: layout_height = "fill_parent"

Android: orientation = "horizontal"

Android: paddingBottom = "3dip"

Android: paddingTop = "1dip"

Android: paddingLeft = "10dip">

<TextView

Android: id = "@ + id/user_name"

Android: layout_width = "100dp"

Android: layout_height = "30dp"

Android: textSize = "10pt"

Android: singleLine = "true"/>

<TextView

Android: id = "@ + id/user_id"

Android: layout_width = "100dp"

Android: layout_height = "30dp"

Android: textSize = "10pt"

Android: singleLine = "true"/>

<TextView

Android: id = "@ + id/user_ip"

Android: layout_width = "wrap_content"

Android: layout_height = "fill_parent"

Android: gravity = "right"

Android: textSize = "10pt"/>

</LinearLayout>

<? Xml version = "1.0" encoding = "UTF-8"?>

<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"

Android: layout_width = "fill_parent"

Android: layout_height = "fill_parent"

Android: orientation = "horizontal"

Android: paddingBottom = "3dip"

Android: paddingTop = "1dip"

Android: paddingLeft = "10dip">

<TextView

Android: id = "@ + id/user_name"

Android: layout_width = "100dp"

Android: layout_height = "30dp"

Android: textSize = "10pt"

Android: singleLine = "true"/>

<TextView

Android: id = "@ + id/user_id"

Android: layout_width = "100dp"

Android: layout_height = "30dp"

Android: textSize = "10pt"

Android: singleLine = "true"/>

<TextView

Android: id = "@ + id/user_ip"

Android: layout_width = "wrap_content"

Android: layout_height = "fill_parent"

Android: gravity = "right"

Android: textSize = "10pt"/>

</LinearLayout>

 

Iii. effect display: