android - 将数据从 Activity 传递到 ViewPager 中的 Fragment

Question

我有一个简单的 Activity，其中包含 TabLayout、ViewPager 和 2 个片段。这是我的活动：

public class ManagementCompanyOverviewActivity extends BaseActivity implements ManagementCompanyOverviewView {

    private ManagementCompanyVPAdapter mVPAdapter;
    private TabLayout mTLContent;
    private ViewPager mVPContent;

    @InjectPresenter
    ManagementCompanyPresenter mPresenter;

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

        mVPAdapter = new ManagementCompanyVPAdapter(getSupportFragmentManager());

        mTLContent = (TabLayout) findViewById(R.id.tl_company_content);

        mVPContent = (ViewPager) findViewById(R.id.vp_company_content);
        mVPContent.setAdapter(mVPAdapter);
        mTLContent.setupWithViewPager(mVPContent);
    }

    @Override
    public void onAboutCompanyInfoReceivedFromServer(AboutCompanyViewModel model) {

    }

Activity 有一个 Presenter（我正在使用 Moxy），Presenter 发送请求，获取答案，创建 JavaObject（视图模型）并使用 getViewState() 将此模型传递给 Activity。我需要将此模型从 Activity 传递给我的一个 Fragment。

Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.fragment_about_company, container, false);

    mTVName = (TextView) view.findViewById(R.id.tv_company_name);
    mTVDirector = (TextView) view.findViewById(R.id.tv_company_director);
    mTVWebsite = (TextView) view.findViewById(R.id.tv_company_website);
    mTVEmail = (TextView) view.findViewById(R.id.tv_company_email);
    mTVPhone = (TextView) view.findViewById(R.id.tv_company_phone);
    mTVSchedule = (TextView) view.findViewById(R.id.tv_company_schedule);
    mTVAddress = (TextView) view.findViewById(R.id.tv_company_address);

    return view;
}

这个片段有一些 TextViews 来显示来自我的模型的信息。如何通过这个模型？如果我知道正确，我应该创建一个侦听器，但是如何？我不完全了解如何使用它们。

Answer 1

好的，我做到了。

1 步：我在我的 Activity 中创建了公共接口并为其设置：

private OnAboutDataReceivedListener mAboutDataListener;

public interface OnAboutDataReceivedListener {
        void onDataReceived(AboutCompanyViewModel model);
    }

public void setAboutDataListener(OnAboutDataReceivedListener listener) {
    this.mAboutDataListener = listener;
}

第 2 步：我在 Fragment 中实现了这个接口并设置了监听器：

public class AboutCompanyFragment extends BaseFragment implements ManagementCompanyOverviewActivity.OnAboutDataReceivedListener

    @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            mActivity = (ManagementCompanyOverviewActivity) getActivity();
            mActivity.setAboutDataListener(this);
        }

第三步：我重写了接口的方法：

@Override
    public void onDataReceived(AboutCompanyViewModel model) {
        mPBName.setVisibility(View.INVISIBLE);
        mPBDirector.setVisibility(View.INVISIBLE);
        mPBWebsite.setVisibility(View.INVISIBLE);
        mPBEmail.setVisibility(View.INVISIBLE);
        mPBPhone.setVisibility(View.INVISIBLE);
        mPBSchedule.setVisibility(View.INVISIBLE);
        mPBAddress.setVisibility(View.INVISIBLE);

        mTVName.setVisibility(View.VISIBLE);
        mTVDirector.setVisibility(View.VISIBLE);
        mTVWebsite.setVisibility(View.VISIBLE);
        mTVEmail.setVisibility(View.VISIBLE);
        mTVPhone.setVisibility(View.VISIBLE);
        mTVSchedule.setVisibility(View.VISIBLE);
        mTVAddress.setVisibility(View.VISIBLE);

        mTVName.setText(model.getCompanyName());
        mTVDirector.setText(model.getDirectorName());
        mTVWebsite.setText(model.getWebsite());
        mTVEmail.setText(model.getEmail());
        mTVPhone.setText(model.getPhone());
        mTVSchedule.setText(model.getWorkTime());
        mTVAddress.setText(model.getAddress());
    }

就是这样。

Answer 2

试试这个 活动中

public String sendData() {
        return YOUR_STRING;
    }

在片段中

YOUR_ACTIVITY activity = (YOUR_ACTIVITY) getActivity();
String getData = activity.SendData();

Answer 3

您可以在 Fragment 中使用 newInstance 方法：

public static MyFragment newInstance(String parameter) {

        Bundle args = new Bundle();
        args.putString("parameter", parameter);
        SfCategoryFragment fragment = new SfCategoryFragment();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (getArguments() != null) {
            parameter = getArguments().getString("parameter");
        }
    }

在你的活动中：

用MyFragment.newInstance("yourParam");代替new MyFragment()

Answer 4

您还可以在适配器的构造函数中获取要在片段中显示的数据并在返回新片段之前设置参数

public class ViewPagerAdapter extends FragmentStatePagerAdapter {
private Weather weather;

ViewPagerAdapter(FragmentManager fm, Weather weather) {
    super(fm);
    this.weather = weather;
}

@Override
public Fragment getItem(int position) {
    switch (position) {
        case 0:
            Bundle bundle = new Bundle();
            WeatherFragment weatherFragment = new WeatherFragment();
            bundle.putParcelable("weather", weather);
            weatherFragment.setArguments(bundle);
            return weatherFragment;
        case 1:
            return new PoemFragment();
        default:
            return new EmptyFragment();
    }
}

Answer 5

来自 Activity 或 ViewPager

Bundle bundle = new Bundle();
bundle.putParcelable(Keys.KEY_ITEM, cardResult);
CardItemFragment cardItemFragment = new CardItemFragment();
cardItemFragment.setArguments(bundle);

从片段

@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
     getBundle();
}


private void getBundle() {
    bundle = getArguments();
    if (null != bundle) {
        if (bundle.containsKey(Keys.KEY_ITEM)) {
            cardResult = bundle.getParcelable(Keys.KEY_ITEM);
        }
    }
}

Answer 6

片段

class SampleFragment : Fragment(), BaseFragmentInteraction {
    override fun updateFragmentData(data: String) {
        Toast.makeText(activity!!, data, Toast.LENGTH_SHORT).show()
    }
}

界面

interface BaseFragmentInteraction {
    fun updateFragmentData(data: String)
}

活动：

view_pager.addOnPageChangeListener(object : ViewPager.OnPageChangeListener {

        override fun onPageSelected(position: Int) {
            val fragmentItem = (view_pager.adapter as FragmentPagerAdapter).getItem(view_pager.currentItem)
            (fragmentItem as BaseFragmentInteraction).updateFragmentData("SomeData")
        }

        override fun onPageScrollStateChanged(state: Int) {}

        override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {}
    })

updateFragmetData 方法将在当前选定的 viewpager 项目片段中调用。您还可以向updateFragmetData 添加标签参数，以便确保调用正确的片段实例。如果需要，您可以在updateFragmetData 实现中调用isVisible 以确保片段可见。

Answer 7

我找到了一种将数据直接传递给片段或片段适配器的新方法

首先你创建一个获取数据的getter方法假设你想获取用户名 你在活动中创建一个方法

public String getUsername(){
return username;
}

然后你从片段以及像这样的片段适配器调用这个方法

片段

(MainActivity) getActivity()).getUsername()

适配器

(MainActivity) context).getUsername()

这种方式还可以帮助您减少对数据库的请求数