Android Learning Notes (4) Intent Primary learning

7th lesson for video tutorials for Joshui teachers

This course explains intent, an abstract description of the action, meaning of intent, and the creation of a intent can give an action to him to execute. Inten is the essence of Android development.
One, click the button to make a call to a specific number

Btn1.setonclicklistener (listener);    Private Onclicklistener Listener =new Onclicklistener () {Intent Intent = new Intent (); @Overridepublic void OnClick (View v) {intent.setaction (intent.action_call);  Intent.setdata (Uri.parse ("tel:110") to give intent the action of calling;  Set phone number startactivity (intent);                 Start Toast.maketext (mainactivity.this, "call", Toast.length_short). Show ();//Display Prompt}};

Two, click the button to send a text message to a specified number

Btn1.setonclicklistener (listener);    Private Onclicklistener Listener =new Onclicklistener () {Intent Intent = new Intent (); @Overridepublic void OnClick (View v) {Case r.id.button1:intent.setaction (intent.action_sendto); Intent.setdata (Uri.parse ("smsto:110")); Intent.putextra ("Sms_body", "nothing, harassment under ~ ~");  Note the format startactivity (intent); Toast.maketext (Mainactivity.this, "Send Text to", Toast.length_short). Show ();//Display Prompt}};

Three, start another activity in one activity
The most basic set of activity to include:
1,activity Class (Xxactivity.java)
2, Layout file (layout/xxx.xml)
3, register the activity in the configuration file
<activity
Android:name= "xxxxx"
Android:label= "XXXX" >
..................
</activity>

With these basic elements, you can invoke the activity in another activity.

For convenience, put this jump in a button click event. Intent intent=new Intent (); Intent.setclass (mainactivity.this,secondactivity.class);//Parameter 1 is Packagecontext, Usually point to mainactivity himself; parameter 2 is the classstartactivity (intent) where the CLS points to the activity to invoke;

Configuration file Join:

<activity android:name= ". Secondactivity "  //Same as activity name android:label=" @string/app_name ">  //Modify </activity> as required

These are the most basic content, if you have a function in the secondactivity, the runtime can be implemented from the mainactivity jump to secondactivity to perform its functions. How do you pass data between the activity?
Sender:

Intent intent=new Intent (); Intent.setclass (Mainactivity.this,secondactivity.class); Intent.putextra ("str", "Hello" ); PutExtra (); Can send many types of data!startactivity (intent);

Receiving Party:

Intent intent=getintent (); Bundle Bundle=intent.getextras ();  What is a bundle? Add to the commentary. String str=bundle.getstring ("str");//characters are stored in Str.

Then it is interesting, it can be understood that: the realization of clicking a button to jump to another interface, then you have to click on a button in the other interface to jump back, and also to return a data.

Defined in Mainactivity:

Private final static int request_code=1;  Equivalent to a special code, for the following definition of intent all, if more than one definition of intent will be assigned a different password, why assign a password? Just to one-to-many situations

The button listens to write:

Intent intent=new Intent (); Intent.setclass (Mainactivity.this,secondactivity.class); Intent.putextra ("str", "Hello" );//startactivity (intent); Startactivityforresult (Intent,request_code)  ; StartActivity (intent); There is no return value, this one. But to write a       //onactivityresult method is as follows

protected void Onactivityresult (int requestcode,int resultcode,intent data)//Learn to construct it with a method constructor! {if (Requestcode==request_code)//Prevent many-to-one {if (Resultcode==secondactivity.result_code)//prevent a-to-many {Bundle bundle= Data.getextras (); String str=bundle.getstring ("Back"); Toast.maketext (Mainactivity.this,str,toast.length_long). Show ();}}}

Defined in Secondactivity:

Public final static int result_code=1;

The button listens to write:

Intent intent=new intemt () Intent.putextra ("Back", "back Data"); Setresult (result_code,intent); Set the return value of finish ();  Kill the current Activity

That's ok! Think about it, is Android software easy?

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Android Learning Notes (4) Intent Primary learning