在哪里放碎片交易？

Question

我希望在应用程序启动后显示homefragment，意思是在menuitem被点击之前，我应该在哪里放置片段事务？谢谢！

public boolean onOptionsItemSelected(MenuItem item) { 
    // The action bar home/up action should open or close the drawer. 
    // ActionBarDrawerToggle will take care of this. 

    switch(item.getItemId()){ 
    case android.R.id.home: 
     if(mDrawerLayout.isDrawerOpen(leftDrawerLayout)){ 
      mDrawerLayout.closeDrawer(leftDrawerLayout); 
     } else { 
      mDrawerLayout.openDrawer(leftDrawerLayout); 
     } 
    case R.id.home: 
     Toast.makeText(getApplicationContext(), "home", Toast.LENGTH_LONG).show(); 
     **ft.replace(R.id.content_frame, homefragment);** 
     break; 

    case R.id.feed: 
     Toast.makeText(getApplicationContext(), "feed", Toast.LENGTH_LONG).show(); 
     ft.replace(R.id.content_frame, feedfragment); 
     break; 
    } 
    ft.commit(); 
    return super.onOptionsItemSelected(item); 

} 

Answer 1

试试这个..

case R.id.home: 
    Toast.makeText(getApplicationContext(), "home", Toast.LENGTH_LONG).show(); 

    FragmentManager fragmentManager = getSupportFragmentManager(); 
    FragmentTransaction ft = fragmentManager.beginTransaction(); 
    ClassName homefragment = new ClassName(); 
    ft.replace(R.id.content_frame, homefragment); 
    ft.commit(); 
    break; 

case R.id.feed: 
    Toast.makeText(getApplicationContext(), "feed", Toast.LENGTH_LONG).show(); 

    FragmentManager fragmentManager = getSupportFragmentManager(); 
    FragmentTransaction ft = fragmentManager.beginTransaction(); 
    ClassName feedfragment = new ClassName(); 
    ft.replace(R.id.content_frame, feedfragment); 
    ft.commit(); 
    break;