day4.27 Summary of _intent and application

First,Intent Object (1) What is Intent?

1) intention, Messenger

2) Value Object ( encapsulates data for data passing )

(2) Application of Intent object

1) Starter Kit (activity,service,broadcastreceiver)

2) Stop the service, release receiver Dynamic registration

3) data transfer ( between Components )

(3) principle and process of Intent object Realization

1) Package Intent Information ( What do you want to do )

2) encapsulating data Information ( for data transfer )

StartActivity (Intent)

StartService (Intent)

Sendbroadcastreceiver (Intent)

The intent is passed to the underlying system through the correlation of the context object , and the underlying component is found based on the specific Intent information encapsulated in the intent, and starts him.

(4) Intended object Application method

1) Explicit Intent ( explicitly specifying the component to start )

2) Implicit intent ( not explicitly specifying the component to start, just passing the string to the underlying system, the underlying to match the object )

Common configuration for an implicit intent object:( implemented in intent-filter )

1) Action (on behalf of specific intent )

2) Category (Representative category, environment)

3) data ( can specify Type )

Description: When you use the implicit intent to start activity , the activity 's intent-filter You need to add a default category in the

Implicit intent is generally used to launch other components across apps .

Extension:pendingintent ( deferred Intent ), This object can encapsulate an intent object inside.

Intent Object Other configuration:

1) setflags (int n): focus on some tags related to startup mode

2) Setdataandtype (Uri,type)

3) ...

Example 1: Explicit Intent vs. implicit intent

public class Mainactivity extends Activity { @Override protected void OnCreate (Bundle savedinstancestate) { Super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main); } an explicit intent public void OnClick01 (View v) { StartActivity (New Intent (This,otheractivity01.class)); Intent intent=new Intent (); Intent.setclass (this, otheractivity01.class); Direct class name Intent.setcomponent (New ComponentName (this, otheractivity01.class)); StartActivity (Intent); Bundle options=// Package animation information Activityoptions.makecustomanimation (This, Android. r.anim.slide_in_left,// can customize it yourself Android. r.anim.slide_out_right). Tobundle (); StartActivity (intent,options); Startactivities (intents) } public void onClick02 (View v) { for this intent object to start activity, the underlying will automatically add a category Intent intent=new Intent ("Action.other"); Adding strings Intent.addcategory ("Category.other"); Intent.settype ("text/*"); StartActivity (Intent); } }

Example 2:Intent passing objects and starting the camera

Class Student implements Serializable{ Direct Implementation interface Private static final long serialversionuid = -1811479799107069425l; String name; Public Student (String name) { This.name=name; } @Override Public String toString () { return name; } } Class Elephant implements Parcelable{ after implementing parcelable , override method private String name; private int age; Public Elephant (String Name,int age) { This.name=name; This.age=age; } deserialization Public Elephant (Parcel source) { This.name=source.readstring (); This.age=source.readint (); } @Override Public String toString () { return name+ "/" +age; } @Override public int describecontents () { TODO auto-generated Method Stub return 0; } /** Serialization * / @Override public void Writetoparcel (Parcel dest, int flags) { Dest.writestring (name); Dest.writeint (age); } use this object to implement a deserialization operation public static final Creator<elephant> creator= New Creator<elephant> () { deserialization @Override Public Elephant Createfromparcel (Parcel source) { return new Elephant (source); } @Override Public elephant[] NewArray (int size) { TODO auto-generated Method Stub return new Elephant[size]; } }; } public class Mainactivity extends Activity { Private ImageView ImageView; @Override protected void OnCreate (Bundle savedinstancestate) { Super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main); imageview= (ImageView) Findviewbyid (R.ID.IMAGEVIEW1); } public void OnClick01 (View v) { Intent intent=new Intent (this,otheractivity01.class); Intent.putextra ("Flag01", true); Bundle B=new Bundle ();//key/value B.putboolean ("Flag02", false); B.putstring ("flag03", "HelloWorld"); Intent.putextra ("Data", b); can encapsulate serialized objects Intent.putextra ("Student", New student (" Chen Jing ")); Intent.putextra ("Elephant", New Elephant (" Elephant ", +)); StartActivity (Intent); } Private Button btn; public void onClick02 (View v) { btn= (Button) v; Startactivityforresult ( New Intent (This,otheractivity02.class),//100 = Request Code ( identifies which request this is ) } activity initiated by the startactivityforresult method This method is executed when it is closed @Override protected void Onactivityresult (int requestcode, int resultcode, Intent data) { LOG.I ("TAG", "resultcode=" +resultcode); if (requestcode==100&&resultcode==200) { String Item=data.getstringextra ("Itemkey"); Btn.settext (item); }else if (requestcode==101) { Bundle Bundle=data.getextras (); Bundle.keyset (); Bitmap bitmap= (Bitmap) bundle.get ("Data"); Imageview.setimagebitmap (BITMAP); } } @Override public boolean Oncreateoptionsmenu (Menu menu) { Getmenuinflater (). Inflate (R.menu.main, menu); return true; } @Override public boolean onoptionsitemselected (MenuItem item) { if (Item.getitemid () ==r.id.cap) { Start the camera program Startactivityforresult ( New Intent (Mediastore.action_image_capture), 101); } return super.onoptionsitemselected (item); } }

public class OtherActivity02 extends Listactivity { @Override protected void OnCreate (Bundle savedinstancestate) { Super.oncreate (savedinstancestate); Setcontentview (R.LAYOUT.ACTIVITY_OTHER_ACTIVITY02); Setlistadapter (New Arrayadapter<string> ( This, Android. R.layout.simple_list_item_1, New string[]{"A", "B", "C"}); } @Override protected void Onlistitemclick (ListView l, View v, int position, long ID) { String item= (String) l.getitematposition (position); Intent intent=new Intent (); Intent.putextra ("Itemkey", item); Setresult (200,// Response code Intent);// Set response data Finish (); } }

Example 3: ImageView pop-up image enabled by default

public void OnClick01 (View v) { Intent intent=new Intent(intent.action_view); Intent.setdataandtype ( Uri.fromfile ( New File ("/mnt/sdcard/png_01.png")), "image/*"); StartActivity (Intent); }

Second,application object (1) What is application?

1) a Context object in Android ( resource access Capability )

2) global Access Objects in Android ( life cycle Same as APP life cycle )

(2)application object application

1) provide global data access for application Components ( shared data )

2) record the corresponding data information ( not suitable for large amounts of data )

For example:

1) User information after successful login.

2) A small amount of data information to be used by each component.

(3) Application of Application object

1) write ( inherit application),

2) Register ( the name attribute of the application specified in the manifest configuration file )

3) life cycle (onCreate,......)

Description: I store data in application and can also store data directly with static attributes.

public class MyApplication extends application { public static user user; }

<application android:name= "Com.tarena.elts.MyApplication"

day4.27 Summary of _intent and application