deviceApp/app/src/main/java/com/xypower/wpywapp/page/DataBindingFragment.java

package com.xypower.wpywapp.page;

import android.content.Context;
import android.os.Bundle;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import androidx.databinding.ViewDataBinding;
import androidx.fragment.app.Fragment;

/**
 * Create by KunMinX at 19/7/11
 */
public abstract class DataBindingFragment extends Fragment {

    protected AppCompatActivity mActivity;
    private ViewDataBinding mBinding;
    private TextView mTvStrictModeTip;

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        mActivity = (AppCompatActivity) context;
    }

    protected abstract void initViewModel();

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

        initViewModel();
    }

    protected abstract DataBindingConfig getDataBindingConfig();

    /**
     * TODO tip: 警惕使用。非必要情况下，尽可能不在子类中拿到 binding 实例乃至获取 view 实例。使用即埋下隐患。
     * 目前方案是于 debug 模式，对获取实例情况给予提示。
     * <p>
     * 如这么说无体会，详见 https://xiaozhuanlan.com/topic/9816742350 和 https://xiaozhuanlan.com/topic/2356748910
     *
     * @return binding
     */
    protected ViewDataBinding getBinding() {
        return mBinding;
    }

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

        DataBindingConfig dataBindingConfig = getDataBindingConfig();

        //TODO tip: DataBinding 严格模式：
        // 将 DataBinding 实例限制于 base 页面中，默认不向子类暴露，
        // 通过这方式，彻底解决 视图调用一致性问题，
        // 如此，视图调用安全性将与基于函数式编程思想 Jetpack Compose 持平。

        // 如这么说无体会，详见 https://xiaozhuanlan.com/topic/9816742350 和 https://xiaozhuanlan.com/topic/2356748910

        ViewDataBinding binding = DataBindingUtil.inflate(inflater, dataBindingConfig.getLayout(), container, false);
        binding.setLifecycleOwner(getViewLifecycleOwner());
        binding.setVariable(dataBindingConfig.getVmVariableId(), dataBindingConfig.getStateViewModel());
        SparseArray<Object> bindingParams = dataBindingConfig.getBindingParams();
        for (int i = 0, length = bindingParams.size(); i < length; i++) {
            binding.setVariable(bindingParams.keyAt(i), bindingParams.valueAt(i));
        }
        mBinding = binding;
        return binding.getRoot();
    }


    @Override
    public void onDestroyView() {
        super.onDestroyView();
        mBinding.unbind();
        mBinding = null;
    }
}