activity的开启和关闭数据返回

1.打开的activity需要在清单文件中设置：<activity name ="" icon="">　　<intent-filter>　　　　<action name="acfroid.intent.action.MAIN">　　　　<catogory name="android.intent.catagory.LAUNCHER"/>　　</intent-filter></activity>2.开启一个activity（1）开启一个一直的activity

Intent intent = new Intent(this, SignInActivity.class); startActivity(intent);
(2)开启一个短信

Intent intent = new Intent(Intent.ACTION_SEND); intent.putExtra(Intent.EXTRA_EMAIL, recipientArray); startActivity(intent);
3.打开activity的数据返回

private void pickContact() {
// Create an intent to "pick" a contact, as defined by the content provider URI
Intent intent = new Intent(Intent.ACTION_PICK, Contacts.CONTENT_URI);
startActivityForResult(intent, PICK_CONTACT_REQUEST);
}
@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// If the request went well (OK) and the request was PICK_CONTACT_REQUEST
if (resultCode == Activity.RESULT_OK && requestCode == PICK_CONTACT_REQUEST) {
// Perform a query to the contact's content provider for the contact's name
Cursor cursor = getContentResolver().query(data.getData(),
new String[] {Contacts.DISPLAY_NAME}, null, null, null);
if (cursor.moveToFirst()) {
　　　　　　　　// True if the cursor is not empty
int columnIndex = cursor.getColumnIndex(Contacts.DISPLAY_NAME)
String name = cursor.getString(columnIndex);
// Do something with the selected contact's name...         }     } }