android dataBinding与BaseObservable实现双向绑定

这里演示代码与页面双向绑定功能 。当用户在页面输入内容，内容自动同步到代码对象赋值，当对象内容发生变化，自动同步到页面上显示。

1、在build.gradle添加dataBinding

dataBinding{
    enabled = true
}

plugins {
    id 'com.android.application'
}

android {
    compileSdk 32

    defaultConfig {
        applicationId "com.nyw.databindingeditview"
        minSdk 21
        targetSdk 32
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        dataBinding{
            enabled = true
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.3.0'
    implementation 'com.google.android.material:material:1.4.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}

2、activity代码

package com.nyw.databindingeditview;

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;

import android.os.Bundle;

import com.nyw.databindingeditview.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
//        setContentView(R.layout.activity_main);
       ActivityMainBinding activityMainBinding= DataBindingUtil.setContentView(this,R.layout.activity_main);
        activityMainBinding.setUserViewModel(new UserViewModel());
    }
}

User类代码

package com.nyw.databindingeditview;

public class User {
    public String name;

    public User(String name) {
        this.name = name;
    }
}

UserViewModel类代码 

package com.nyw.databindingeditview;

import android.util.Log;

import androidx.databinding.BaseObservable;
import androidx.databinding.Bindable;

public class UserViewModel  extends BaseObservable {
    private User user;

    public UserViewModel() {
        this.user=new User("张三");
    }

    
    @Bindable
    public String getName(){
        return user.name;
    }

    
    public void setName(String name){
        if (name!=null&&!name.equals(user.name)){
            //当内容不等于空并且数据发生变化了
            user.name=name;
            Log.d("printTextMsg","set name "+name);
            //通知更新页面
            notifyPropertyChanged(BR.name);
        }
    }

}

页面代码如下，页面中也是添加了dataBinding的，光标放到第一行第一个位置 ，按Alt+回车可以选择修改页面布局，改为dataBinding页面设置，如下