Android first line code -2.activity basic usage

Summary:

This section is mainly concerned with activity creation, title bar hiding, button binding method (Toast usage), menu usage, activity destruction

1.activity Creation and Registration

Create:

public class Testactivity extends Activity {    @Override    protected void onCreate (Bundle savedinstancestate) {        super.oncreate (savedinstancestate);        Setcontentview (R.layout.activity_main);    }}

Registered:

        <ApplicationAndroid:allowbackup= "true"Android:icon= "@drawable/ic_launcher"Android:label= "@string/app_name"Android:theme= "@style/apptheme" >            <ActivityAndroid:name=". Testactivity "Android:label= "Testactivity" >                <Intent-filter>                    <ActionAndroid:name= "Android.intent.action.MAIN" />                    <categoryAndroid:name= "Android.intent.category.LAUNCHER" /> </Intent-filter>            </Activity>        </Application>

2. Hide the title bar

The interface is called in the OnCreate in testactivity

 Public class extends Activity {    @Override    protectedvoid  onCreate (Bundle savedinstancestate) {         Super . OnCreate (savedinstancestate);        Requestwindowfeature (window.feature_no_title);        Setcontentview (R.layout.activity_main);    }}

3. Bind a button to a method (toast as an example)

(1) Create button

New button in Activity_main.xml (layout)

    <button        android:id= "@+id/button_1"        android:layout_width= "Match_parent"         Android:layout_height= "Wrap_content"        android:text= "Alex"        />

(2) Bind method by ID

 Public classTestactivityextendsActivity {@Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Requestwindowfeature (Window.feature_no_title);        Setcontentview (R.layout.activity_main); FinalButton button_test =(Button) Findviewbyid (r.id.button_1); Button_test.setonclicklistener (NewView.onclicklistener () {@Override Public voidOnClick (View v) {toast.maketext (testactivity. This, "You click Test button", Toast.length_short). Show ();    }        }); }}

3.menu use

(1). Add Menu

The default corresponding menu in Res/menu, here is Menu_main.xml, here add two options

<Menuxmlns:android= "Http://schemas.android.com/apk/res/android" >    <ItemAndroid:id= "@+id/add_item"Android:title= "Add"/>    <ItemAndroid:id= "@+id/remove_item"Android:title= "Remove"/></Menu>

(2) rewrite the Oncreateoptionsmenu to allow the menu bar to show up

    @Override Public    Boolean oncreateoptionsmenu (Menu menu) {        getmenuinflater (). Inflate (R.menu.menu_main, menu);        return true;    }

(3) Add a response event to the menu bar

    @Override Public    boolean onoptionsitemselected (MenuItem menu) {        switch (Menu.getitemid ()) {case            R.id.add _item:                Toast.maketext (This, "You clicked Add", Toast.length_short). Show ();                break;            Case R.id.remove_item:                toast.maketext (This, "You clicked Remove", Toast.length_short). Show ();                break;            Default:        }        return true;    }

4. Activity Destruction

The destruction activity is relatively simple, and binding an action is OK.

Button1.setonclicklistener (new  Onclicklistener () {        @Override        public void OnClick (View v) {            finish ();}});

Android first line code -2.activity basic usage