基于ViewBinding 和 DataBinding的BaseActivity

看完这篇文章，决定自己写一个

1 build.gradle(:app) 添加ViewBinding & ViewDataBinding支持

android {
    ...
    buildFeatures {
        dataBinding true
        viewBinding true
    }
    ...
}

2 写基类 BaseActivity

package com.jhj.mymvvm.base

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.viewbinding.ViewBinding

/**
 * @author 刘建波
 * 3/7/22
 * 描述：Activity 基类
 */
abstract class BaseActivity<Binding : ViewBinding> : AppCompatActivity() {

    lateinit var mBinding: Binding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        mBinding = bindFactory()
        performBusinessLogic()
    }

    /**
     * 子类决定去绑定 ViewBinding 抑或 ViewDataBinding 
     */
    abstract fun bindFactory(): Binding

    /**
     * 绑定成功，执行业务逻辑
     */
    abstract fun performBusinessLogic()

}

public abstract class ViewDataBinding extends BaseObservable implements ViewBinding

我们可以看到，ViewDataBinding 实现了 ViewBinding 接口，换句话说，二者都是 ViewBinding，根据这个我们可以在基类中用泛型去做了。基类中只负责抽象，让子类去负责实现。

2.1 MainActivity(实现ViewBinding的子类)

package com.jhj.mymvvm

import android.view.View
import com.jhj.mymvvm.base.BaseActivity
import com.jhj.mymvvm.base.helper.JumpHelper
import com.jhj.mymvvm.databinding.ActivityMainBinding

class MainActivity : BaseActivity<ActivityMainBinding>(), View.OnClickListener {

    /**
     * [BaseActivity] 的 ViewBinding 实例
     */
    override fun bindFactory(): ActivityMainBinding {
        val binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)
        return binding
    }

    override fun performBusinessLogic() {
        mBinding.tvDataBinding.text = "[BaseActivity] 的 ViewBinding 实例"
        mBinding.tvDataBinding.setOnClickListener(this)
    }

    override fun onClick(view: View?) {
        when (view?.id) {
            R.id.tvDataBinding -> {
                val intent = Intent(this, DataBindingActivity::class.java)
                startActivity(intent)
            }
        }
    }

}

对应的 activity_main.xml文件

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/tvDataBinding"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_margin="10dp"
        android:background="@color/b_blue"
        android:gravity="center"
        android:text="DataBinding"
        android:textColor="@color/white"
        android:textSize="20sp" />

</LinearLayout>

2.2 DataBindingActivity(实现ViewDataBinding的子类)

package com.jhj.mymvvm.base.databinding

import androidx.databinding.DataBindingUtil
import com.jhj.mymvvm.R
import com.jhj.mymvvm.base.BaseActivity
import com.jhj.mymvvm.databinding.ActivityDataBindingBinding

class DataBindingActivity : BaseActivity<ActivityDataBindingBinding>() {

    /**
     * [BaseActivity] 的 ViewDataBinding 实例
     */
    override fun bindFactory(): ActivityDataBindingBinding {
        return DataBindingUtil.setContentView(this, R.layout.activity_data_binding)
    }

    override fun performBusinessLogic() {
        mBinding.content = "[BaseActivity] 的 ViewDataBinding 实例"
    }

}

对应的 activity_data_binding.xml文件

<?xml version="1.0" encoding="utf-8"?>

<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <data>

        <variable
            name="content"
            type="java.lang.String" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".MainActivity">

        <androidx.appcompat.widget.AppCompatTextView
            android:id="@+id/tvDataBinding"
            android:layout_width="match_parent"
            android:layout_height="40dp"
            android:layout_margin="10dp"
            android:background="@color/b_blue"
            android:gravity="center"
            android:text="@{content}"
            android:textColor="@color/white"
            android:textSize="20sp" />

    </LinearLayout>
</layout>