自動選擇的商品

Question

如何在打開頁面時自動選擇一個項目（例如「R.id.nav_code」）？

@Override 
public boolean onNavigationItemSelected(MenuItem item) { 
    int id = item.getItemId(); 
    FragmentManager fragmentManager = getFragmentManager(); 
if (id == R.id.nav_code) { 
    fragmentManager.beginTransaction() 
      .replace(R.id.content_frame 
        , new code()) 
      .commit(); 
} else if (id == R.id.nav_documentation) { 
    fragmentManager.beginTransaction() 
      .replace(R.id.content_frame 
        , new documentation()) 
      .commit(); 
} else if (id == R.id.nav_number) { 
    fragmentManager.beginTransaction() 
      .replace(R.id.content_frame 
        , new number()) 
      .commit(); 
} 
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
drawer.closeDrawer(GravityCompat.START); 
    return true; 
} 

Answer 1

如果你想每次啓動默認片段您的活動開始，然後將此代碼添加到您的活動onCreate方法你希望你的活動開始時，開始新的片段

@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.YourLayout); 

FragmentManager fragmentManager=getFragmentManager(); 
FragmentTransaction transaction=fragmentManager.beginTransaction(); 
code_Fragment code=new code_Fragment(); //Create Object Of your Fragment 
transaction.replace(R.id.FragmentLoginRegistration,code); 
transaction.commit(); 
}