activity->fragment

在onCreate(){

    select(0);

}



public void select(int i) {
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    hideFragment(ft);
    switch(i){
    case 0:
        if(gzFragment==null){
            gzFragment = new GongZuoWangFragment();
            ft.add(R.id.fl_main,gzFragment);
        }else{
        ft.show(gzFragment);
        }
    break;

    case 1:
        if(fwFragment==null){
            fwFragment = new FuWuWangFragment();
            ft.add(R.id.fl_main,fwFragment);
        }else{
            ft.show(fwFragment);
        }
    break;

    case 2:
        if(lxFragment==null){
            lxFragment = new LianXiWangFragment();
            ft.add(R.id.fl_main,lxFragment);
        }else{
            ft.show(lxFragment);
        }
    break;

    case 3:
        if(zyFragment==null){
            zyFragment = new ZhiYuanZheFragment();
            ft.add(R.id.fl_main,zyFragment);
        }else{
            ft.show(zyFragment);
        }
    break;

    case 4:
        if(!spIsLogin.getBoolean("IsLogin",false)){
            if(grFragment2==null){
                grFragment2 = new GeRenFragment2();
                ft.add(R.id.fl_main,grFragment2);
            }else{
                ft.show(grFragment2);
            }
        }else{
            if(grFragment==null){
                grFragment = new GeRenFragment();
                ft.add(R.id.fl_main,grFragment);
            }else{
                ft.show(grFragment);
        }
    }
    break;

    }

    ft.commit();
}

private void hideFragment(FragmentTransaction ft) {
    if(gzFragment!=null){
        ft.hide(gzFragment);
    }
    
    if(fwFragment!=null){
        ft.hide(fwFragment);
    }
    
    if(lxFragment!=null){
        ft.hide(lxFragment);
    }
    
    if(zyFragment!=null){
        ft.hide(zyFragment);
    }

    if(grFragment!=null){
        ft.hide(grFragment);
    }

    if(grFragment2!=null){
        ft.hide(grFragment2);
    }

}