10-Day Learning Android Development (2-1)-Core components activity

Activity, Service, broadcast Receiver, Content provide are the four core components of Android, Activity is a window that interacts with the user in three states: Run, pause, stop

Seven methods:

 protected voidOnCreate(BundleSavedinstancestate);

protected voidOnStart();

protected voidOnrestart();

protected voidOnresume();

protected voidOnPause();

protected voidOnStop();

protected voidOnDestroy();

Life cycle diagram, see:

Http://developer.android.com/reference/android/app/Activity.html

can see:

Running status: In Onresume after

paused state: OnPause after the pause state, if there are other higher priority programs that require memory to run, this program may be stopped, freeing up memory

onpause- " Onresume

Onstop->>onstart

Tip: Adjust the window (code) font size

Windows à Preference à General->appearance->colorsand fonts->text Font à Edit

Case DAY2-1:

1) New Android application Project

2) Create a new class Show1,

activity superclass :activity "

androidmanifest.xml

androidmanifest.xml applicationnodes, "Add"- androidmanifest.xml Add a line:

<activity android:name= "Show1" ></activity>

4) Add a new class layout

GiveNewclass, add a content layout, right-click:Res->layout, addingAndroidxml File,name is: Show1,Layout method:LinearLayout

Add a text:

<textview
Android:id= "@+id/txtmyview"
Android:layout_width= "Wrap_content"
android:layout_height= "Wrap_content"
android:text= "MyView"/>

5) new class and content layout bindings, add Setcontentview (R.LAYOUT.SHOW1) to the new class code file as follows:

public class Show1 extends Activity {
@Override
protected void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Setcontentview (R.LAYOUT.SHOW1);

6) in the main page layout, add the button event, passing the string to Show1:

public class Mainactivity extends Actionbaractivity {

Private Button btnstart;

@Override
protected void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Setcontentview (R.layout.activity_main);

Btnstart= (Button) Findviewbyid (R.id.butstart);

Btnstart.setonclicklistener (New View.onclicklistener () {

@Override
public void OnClick (View v) {
Intent i=new Intent (mainactivity.this,show1.class);
Bundle Data=new Bundle ();
Data.putstring ("txt", "Hello Show1");
I.putextras (data);
Startactivityforresult (i,0);

Finish ();//If this is the case, the page will be closed
}
});
}

7) Accept the string in the Show1 class:

         txtmyview.settext (TXT);
        
    }
}

This article is from "Blue Sea Tactics" blog, please make sure to keep this source http://wanxl.blog.51cto.com/2129901/1587964

10-Day Learning Android Development (2-1)-Core components activity