添加和替换Fragments，在android中没有按预期工作

Question

我正在尝试安卓片段，我无法理解这一点;请帮忙

public class MainActivity extends FragmentActivity {
    private static final String TAG = "MyActivity";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (findViewById(R.id.fragment_container) !=null) {
            if(savedInstanceState!=null){
                return ;
            }
            ArticleFragment first_fragment = new ArticleFragment();
            HeadlineFragment second_fragment = new HeadlineFragment();
            first_fragment.setArguments(getIntent().getExtras());
            second_fragment.setArguments(getIntent().getExtras());
            FragmentTransaction manager=getSupportFragmentManager().beginTransaction();
            manager.add(R.id.fragment_container, first_fragment,"first");
            manager.add(R.id.yo, second_fragment,"second");
            manager.commit();
        }
    }

现在我想在按下按钮时删除second_fragment并将其替换为另一个按钮。所以我试过这个

if(getSupportFragmentManager().findFragmentByTag("second")!=null) {
                    Log.d(TAG,"found");
                    abc newFragment = new abc();
                    Bundle args = new Bundle();
                    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
                    transaction.remove(getSupportFragmentManager().findFragmentByTag("second"));
                    transaction.add(R.id.fragment_container,newFragment,"third");
                    transaction.addToBackStack(null);
                    transaction.commit();
                }

但是当我一次又一次按下该按钮时，if条件通过。 这有什么不对？

Answer 1

不要删除和添加。只需用新的片段替换第二个片段。你将完成。