How to start Fragment from an Activity

问题:

I already want to start my RecipientFragment from my MainActivity and pass data onto the Fragment from my MainActivity. Here is the code that I have implemented. But the fragment does not start.

Bundle bundle = new Bundle();
bundle.putString(ParseConstants.KEY_FILE_TYPE, fileType);
RecipientsFragment keyfile = new RecipientsFragment();
keyfile.setArguments(bundle);
Fragment newFragment = new RecipientsFragment();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.commit();

I also want to know how to pass intent.setData and get that data in Fragment. Currently I have below code:

RecipientFragment

mMediaUri = getActivity().getIntent().getData();

MainActivity

Intent recipientsIntent = new Intent(this, RecipientsFragment.class);
        recipientsIntent.setData(mMediaUri);

回答1:

You can either add or replace fragment in your activity. Create a FrameLayout in activity layout xml file.

Then do this in your activity to add fragment:

FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(R.id.container,YOUR_FRAGMENT_NAME,YOUR_FRAGMENT_STRING_TAG);
transaction.addToBackStack(null);
transaction.commit();

And to replace fragment do this:

FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.container,YOUR_FRAGMENT_NAME,YOUR_FRAGMENT_STRING_TAG);
transaction.addToBackStack(null);
transaction.commit();

See Android documentation on adding a fragment to an activity or following related questions on SO:

Difference between add(), replace(), and addToBackStack()

Basic difference between add() and replace() method of Fragment

Difference between add() & replace() with Fragment's lifecycle

回答2:

Firstly, you start Activities and Services with an intent, you start fragments with fragment transactions. Secondly, your transaction isnt doing anything. Change it to something like:

FragmentTransaction transaction = getFragmentManager();
    transaction.beginTransaction()
        .replace(R.layout.container, newFragment) //<---replace a view in your layout (id: container) with the newFragment 
        .commit();

回答3:

Simple way

1. Create a new java class

   public class ActivityName extends FragmentActivity {
   @Override
    public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
       if (savedInstanceState == null){
       getSupportFragmentManager().beginTransaction()
               .add(android.R.id.content, new Fragment_name_which_you_wantto_open()).commit();}
    }
   }
   

2. in your activity where u want to call fragment

    Intent i = new Intent(Currentactivityname.this,ActivityName.class);
    startActivity(i);
   

Another Method

1. Place frame layout in your activity where u want to open fragment

     <FrameLayout
           android:id="@+id/frameLayout"
           android:layout_width="match_parent"
           android:layout_height="wrap_content">
       </FrameLayout>
   

2. Paste this code where u want to open fragment

       Fragment mFragment = null;
           mFragment = new Name_of_fragment_which_you_want_to_open();
           FragmentManager fragmentManager = getSupportFragmentManager();
           fragmentManager.beginTransaction()
                   .replace(R.id.frameLayout, mFragment).commit();
   

回答4:

You Can Start Activity and attach RecipientsFragment on it , but you cant start Fragment