Android

Question

我正在创建一个 Android 应用程序，它使用主 activity 和几个片段。主要 activity 是所有内容的最小 "control"，每个片段显示不同的屏幕，显示不同的信息。这是我的主要 activity 的一些代码：

public class MainMenu extends FragmentActivity implements FirstMenu.FragmentListener, Checklist.FragmentListener,
    Tool.FragmentListener{

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_menu);

    FirstMenu firstMenu = new FirstMenu();

    getSupportFragmentManager().beginTransaction().add(R.id.fragment_container,
            firstMenu).commit();
}

public void changeScreen() {

    Checklist checklist = new Checklist();

    android.support.v4.app.FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();

    transaction.replace(R.id.fragment_container, checklist);
    transaction.addToBackStack(null);
    transaction.commit();

}

public void changeScreenTwo() {

    ChemicalCheckList chemChecklist = new ChemicalCheckList();

    android.support.v4.app.FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();

    transaction.replace(R.id.fragment_container, chemChecklist);
    transaction.addToBackStack(null);
    transaction.commit();

}

这是我第一个显示菜单的片段的代码：

public class FirstMenu extends Fragment {
    FragmentListener fragmentChanger;

    public interface FragmentListener {
        public void changeScreen();
        public void changeScreenFour();
        public void changeScreenFive();
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            fragmentChanger = (FragmentListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException();
        }
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        container.removeAllViews();
        View view = inflater.inflate(R.layout.menu, container, false);

        Button checkListButton = (Button) view.findViewById(R.id.checklistButton);
        Button toolButton = (Button) view.findViewById(R.id.toolButton);
        Button timeFuseButton = (Button) view.findViewById(R.id.timeFuseCalculator);
        Button blastFragButton = (Button) view.findViewById(R.id.blastFragButton);
        Button demoButton = (Button) view.findViewById(R.id.demoButton);



        checkListButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        buttonClicked(v);
                    }
                }
        );

        toolButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        toolButtonClicked(v);
                    }
                }
        );

        demoButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        demoButtonClicked(v);
                    }
                }
        );




       blastFragButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getActivity(), BlastFrag.class);
                startActivity(intent);
            }
        });
        timeFuseButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getActivity(), TimeFuse.class);
                startActivity(intent);
            }
        });

        return view;

    }

    public void buttonClicked( View v ) {
        fragmentChanger.changeScreen();
    }
    public void toolButtonClicked( View v ) {
        fragmentChanger.changeScreenFour();
    }
    public void demoButtonClicked( View v ) {
        fragmentChanger.changeScreenFive();
    }
}

这是第二个片段的代码，它使用方法 changeScreen();

显示在屏幕上

public class Checklist extends Fragment{
    FragmentListener fragmentAlternator;

    public interface FragmentListener {
        public void changeScreenTwo();
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            fragmentAlternator = (FragmentListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException();
        }
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        container.removeAllViews();
        View view = inflater.inflate(R.layout.checklists, container, false);

        Button chemButton = (Button) view.findViewById(R.id.chemButton);


        chemButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        buttonClicked(v);
                    }
                }
        );

        return view;
    }
    public void buttonClicked( View v ) {
        fragmentAlternator.changeScreenTwo();
    }
}

我有更多片段使用更多方法显示在屏幕上，例如：changeScreenTwo()、changeScreenThree()、changeScreenFour() 等。这些方法的代码几乎完全相同。唯一的区别是它从不同的 classes 创建不同的对象。我想知道我目前的做法是否合适，或者是否有一种方法可以将所有这些 "changeScreen" 方法变成一个方法，并简单地传入每种类型的 class 作为一个参数。我找遍了所有地方，似乎找不到我在这种特殊情况下寻找的答案。

Answer 1

传入片段索引并使用它来选择片段类型。

public void changeScreen(int position) {
    switch(position){
        case 0:
            getSupportFragmentManager().beginTransaction()
                .replace(R.id.fragment_container, new Checklist())
                .addToBackStack(null)
                .commit();
            break;
        case 1:
            getSupportFragmentManager().beginTransaction()
                .replace(R.id.fragment_container, new ChemicalCheckList())
                .addToBackStack(null)
                .commit();
            break;
    }
}

Android - 在 Activity 中更改片段

Android - Changing Fragments within an Activity

fragment