Android: Understanding Intents and starting activity from it..

Basic understandings of Android Intents and starting activity from it..
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Toast and its simplest work to show the text:

Toast.maketext(getActivity(),textview.getText().toString(),Toast.LENGTH_SHORT).show();


Starting Activity:

>startActivity(i); //if i is a defined Intent object already;
>startActivity(new Intent("name of the class from manifest.xml");
>startActivity(new Intent(this, "name of the java class");


Intents in Android and its invocations 

1>Intent i = new Intent(android.content.Intent.ACTION_VIEW,Uri.parse("http://website"));
startActivity(i);
2> Intent i = new Intent(android.content.Intent.ACTION_VIEW);
i.setData(Uri.parse("http://website"));
startActivity(i);
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Uri.parse can take values as such to be shown:
Like :>
geo---for map application or activity;
tel--->for telephonic activity
http-->for web browser activity
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3>For default action or dynamic data:
  Intent i = new Intent(android.content.Intent.ACTION_PICK);
  i.setType(ContactsContract.Contacts.CONTENT_TYPE);
  startActivity(i);
  
  Intent can contain the following information:
    >Action
    >Data
    >Type
    >Category
 >To choose from options..
 add:
    > category in the manifest file:
       eg.       and 
       add in the main java file
       as 
       Intent i = new Intent(android.content.Intent.ACTION_VIEW,Uri.parse("http://webaddress"));
 startActivity(Intent.createChooser(i,"choose");