Android DataBinding使用的基础封装

一、简介

本文是databinding使用的简单封装，主要是在基类BaseActivity和BaseFragment中

二、具体步骤

1.在build.gradle中开启databinding

dataBinding { enabled = true }

2.在BaseActivity的封装，主要是通过反射的方式获取。如下

package com.zw.databindingdemo.java;

import android.os.Bundle;
import android.view.LayoutInflater;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.ViewDataBinding;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;

/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
public abstract class BaseActivity<VB extends ViewDataBinding> extends AppCompatActivity {

    public VB mBinding;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        createBinding();
    }

    private void createBinding() {
        Class<VB> vbClass = getVbClass();
        try {
            if (vbClass == null) {
                return;
            }
            Method method = vbClass.getMethod("inflate", LayoutInflater.class);
            mBinding = (VB) method.invoke(null, getLayoutInflater());
            setContentView(mBinding.getRoot());
        } catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
            e.printStackTrace();
        }
    }

    private Class<VB> getVbClass() {
        ParameterizedType parameterizedType = (ParameterizedType) this.getClass().getGenericSuperclass();
        if (parameterizedType == null) {
            return null;
        }
        Class<VB> vbClass = (Class<VB>) parameterizedType.getActualTypeArguments()[0];
        return vbClass;
    }
}

3.在Activity中使用如下

package com.zw.databindingdemo.java;

import android.os.Bundle;

import androidx.annotation.Nullable;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import com.zw.databindingdemo.databinding.ActivityTestBinding;

/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
public class TestActivity extends BaseActivity<ActivityTestBinding> {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mBinding.tvName.setText("测试 java Activity");
        mBinding.btnGo.setOnClickListener(v -> {
            initFragment();
        });
    }

    private void initFragment() {
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();
        ft.replace(mBinding.frameLayout.getId(), new TestFragment());
        ft.commit();

    }
}

4.在BaseFragment的封装

package com.zw.databindingdemo.java;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

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

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;



/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
public abstract class BaseFragment<VB extends ViewDataBinding> extends Fragment {


    public VB mBinding;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        createBinding(inflater, container);
        return mBinding.getRoot();
    }

    private void createBinding(LayoutInflater inflater, ViewGroup container) {
        Class<VB> vbClass = getVbClass();
        try {
            if (vbClass == null) {
                return;
            }
         /*   Method method = vbClass.getMethod("inflate", LayoutInflater.class, ViewGroup.class, Boolean.class);*/
            Method method = vbClass.getMethod("inflate", LayoutInflater.class);
            mBinding = (VB) method.invoke(null, inflater);
        } catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
            e.printStackTrace();
        }
    }

    private Class<VB> getVbClass() {
        ParameterizedType parameterizedType = (ParameterizedType) this.getClass().getGenericSuperclass();
        if (parameterizedType == null) {
            return null;
        }
        return (Class<VB>) parameterizedType.getActualTypeArguments()[0];
    }
}

5.在Fragment的使用如下

package com.zw.databindingdemo.java;

import android.os.Bundle;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import com.zw.databindingdemo.databinding.FragmentTestBinding;


/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
public class TestFragment extends BaseFragment<FragmentTestBinding> {

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        mBinding.tvName.setText("测试 java Fragment");
    }
}

6.Kotlin 版本

 package com.zw.databindingdemo.kotlin

import android.os.Bundle
import android.view.LayoutInflater
import androidx.appcompat.app.AppCompatActivity
import androidx.databinding.ViewDataBinding
import java.lang.reflect.ParameterizedType

/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
abstract class BaseActivityKotlin<VB : ViewDataBinding> : AppCompatActivity() {

    public lateinit var mBinding: VB

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        mBinding = createBinding()
        setContentView(mBinding.root)
    }

    private fun createBinding(): VB {
        val vbClass = getVBClass()
        val method = vbClass.getMethod("inflate", LayoutInflater::class.java)

        return method.invoke(null, layoutInflater) as VB
    }

    @Suppress("UNCHECKED_CAST")
    private fun getVBClass(): Class<VB> {
        val type = javaClass.genericSuperclass as ParameterizedType
        return type.actualTypeArguments[0] as Class<VB>
    }
}

package com.zw.databindingdemo.kotlin

import android.os.Bundle
import com.zw.databindingdemo.databinding.ActivityTestKotlinBinding

/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
class TestActivityKotlin: BaseActivityKotlin<ActivityTestKotlinBinding>() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        mBinding.tvName.text = "测试 Kotlin Activity"
        mBinding.btnGo.setOnClickListener { initFragment() }
    }

    private fun initFragment() {
        val fm = supportFragmentManager
        val ft = fm.beginTransaction()
        ft.replace(mBinding.frameLayout.id, TestFragmentKotlin())
        ft.commit()
    }
}

package com.zw.databindingdemo.kotlin

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.databinding.ViewDataBinding
import androidx.fragment.app.Fragment
import java.lang.reflect.ParameterizedType

/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
abstract class BaseFragmentKotlin<VB : ViewDataBinding> : Fragment() {


    public lateinit var mBinding: VB

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        mBinding = createBinding(inflater, container)
        return mBinding.root
    }

    private fun createBinding(inflater: LayoutInflater, container: ViewGroup?): VB {
        val vbClass = getVBClass()
        val method = vbClass.getMethod(
            "inflate",
            LayoutInflater::class.java,
            ViewGroup::class.java,
            Boolean::class.java
        )

        return method.invoke(null, inflater, container, false) as VB
    }

    @Suppress("UNCHECKED_CAST")
    private fun getVBClass(): Class<VB> {
        val type = javaClass.genericSuperclass as ParameterizedType
        return type.actualTypeArguments[0] as Class<VB>
    }

}

package com.zw.databindingdemo.kotlin

import android.os.Bundle
import android.view.View
import com.zw.databindingdemo.databinding.FragmentTestKotlinBinding

/**
 * 描述:
 * @author: zw
 * @time: 2023/5/22 17:33
 */
class TestFragmentKotlin : BaseFragmentKotlin<FragmentTestKotlinBinding>() {

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        mBinding.tvName.text = "测试 Kotlin Fragment"
    }
}