Android's ToDoList detailed

ToDoList is an Android starter program that contains two controls, EditText (edit text), ListView (List view), placed in LinearLayout (linear layout);

Need to rewrite the listening key (Setonkeylistener) and use the adapter (Adapter) to correlate;

1. Code for the main interface (Activity_to_do_list.xml):

<linearlayout xmlns:android= "http://schemas.android.com/apk/res/android" xmlns:tools= "http:// Schemas.android.com/tools "android:orientation=" vertical "android:layout_width=" match_parent "Android:layout_h" eight= "Match_parent" android:paddingleft= "@dimen/activity_horizontal_margin" android:paddingright= "@dimen Activity_horizontal_margin "android:paddingtop=" @dimen/activity_vertical_margin "android:paddingbottom=" @dimen
        Activity_vertical_margin "tools:context=" mzx.spike.todolist.app.ToDoListActivity "> <edittext
        Android:id= "@+id/myedittext" android:layout_width= "match_parent" android:layout_height= "Wrap_content"   
      
    android:hint= "@string/additemhint" android:contentdescription= "@string/additemcontentdescription"/> <listview android:id= "@+id/mylistview" android:layout_width= "Match_parent" Androi d:layout_height= "Wrap_content"/> </Linearlayout> 

Location: Res->layout->activity_to_do_list.xml

Attention:

1. All controls, you must specify the Layout_width (control width), layout_height (control height), two properties, the Android system will make the corresponding match;

2. Id attribute, is to register in the R file, in the program logic (Java file) use, so use "@+id", "+" means added meaning;

3. LinearLayout control (linear), need to indicate the orientation (direction), so that its internal control orderly arrangement;

4. Layout matching two commonly used attributes: Match_parent (matching the parent control, fill), wrap_content (enclosing the content, according to the content of the minimized);

2. Code for string (strings.xml):

<?xml version= "1.0" encoding= "Utf-8"?>  
<resources>  
      
    <string name= "App_name" >ToDoList< /string>  
    <string name= "Additemhint" >new to do item</string> <string  
    " Additemcontentdescription ">new to do item</string>  
    <string name=" action_settings ">Settings</" String>  
      
</resources>

Location: Res->values->string.xml

Attention:

Using the form of strings, you can separate the presentation layer from the application logic layer and extend other languages;

3. Code for Program Logic (Todolistactivity.java):

Package Mzx.spike.todolist.app;  
Import Android.os.Bundle;  
Import android.support.v7.app.ActionBarActivity;  
Import android.view.KeyEvent;  
Import Android.view.Menu;  
Import Android.view.MenuItem;  
Import Android.view.View;  
Import Android.widget.ArrayAdapter;  
Import Android.widget.EditText;  
      
Import Android.widget.ListView;  
      
      
Import java.util.ArrayList; public class Todolistactivity extends actionbaractivity {@Override protected void onCreate (Bundle savedi  
        Nstancestate) {super.oncreate (savedinstancestate);  
      
        Setcontentview (r.layout.activity_to_do_list); Get a reference to the UI component//view this column more highlights: Http://www.bianceng.cnhttp://www.bianceng.cn/OS/extra/ListView Mylistview = (listvie  
        W) Findviewbyid (R.id.mylistview); Final EditText Myedittext = (edittext) Findviewbyid (R.id.myedittext); Final expression constants//Get references to UI components final arraylist<string> Todoitems = new Arraylist<  
      
        String> ();  
        Create Arrayadapter to speak array binding to ListView final arrayadapter<string> AA; AA = new Arrayadapter<string> (this, Android.  
      
        R.layout.simple_list_item_1, Todoitems);  
      
        Binding the Arrayadapter to the ListView mylistview.setadapter (AA);
            Listen for the Myedittext enter key Myedittext.setonkeylistener (new View.onkeylistener () {@Override public Boolean OnKey (view view, int i, keyevent keyevent) {if (keyevent.getaction () = = Keyevent.action _down) if ((i = = Keyevent.keycode_dpad_center) | | (i = = Keyevent.keycode_enter))  
                        {todoitems.add (0, Myedittext.gettext (). toString ());  
                        Aa.notifydatasetchanged ();  
                        Myedittext.settext ("");  
                    return true;  
            return false;  
    }  
        }); } @OverrIDE public boolean Oncreateoptionsmenu (Menu menu) {//Inflate the ' menu; this adds items to T  
        He action Bar if it is present.  
        Getmenuinflater (). Inflate (r.menu.to_do_list, menu);  
    return true; @Override public boolean onoptionsitemselected (MenuItem Item) {//Handle Action Bar Item CLI Cks here. The action bar would//automatically handle clicks on the Home/up button, so long//As you specify a  
        Parent activity in Androidmanifest.xml.  
        int id = item.getitemid ();  
        if (id = = r.id.action_settings) {return true;  
    return super.onoptionsitemselected (item); }  
      
}

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