Android 数据绑定视图 dataBinding

1,在build.gradle中,添加一下代码

android {
    ...
    dataBinding {
        enabled = true
    }
}

2.在布局文件activity_main.xml中添加一下代码,或者直接点击小灯泡 ,

myViewMdel是绑定的模型

    
        
    

    
        ........
    

3,viewModel来创建liveData模型

package com.example.binddata;

import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;

public class MyViewModel extends ViewModel {
    //定义绑定变量
    private MutableLiveData number;

    //获取变量方法
    public MutableLiveData getNumber() {
        if(number == null){
            number = new MutableLiveData<>();
            number.setValue(0);
        }
        return number;
    }
    //增加
    public void add(int n){
        number.setValue(number.getValue()+n);
    }
}

4,如果已经在activity_main.xml中添加了上述代码,则MainActivity.java中,就可以直接使用一下类

MyViewModel myViewModel;
    ActivityMainBinding binding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = DataBindingUtil.setContentView(this,R.layout.activity_main);
        myViewModel = ViewModelProviders.of(this).get(MyViewModel.class);
        binding.setData(myViewModel);
        binding.setLifecycleOwner(this);
    }

5,在xml中,直接绑定