LiveData with java

开始

LiveData需要配合ViewModel使用, 需要导入第三方库

    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.8.2@aar'

ViewModel用法

创建自己的ViewModel

public class MyViewModel extends ViewModel {
    private MutableLiveData<String> name;
    private MutableLiveData<User> user;

    public MyViewModel() {
        name = new MutableLiveData<>();
        user = new MutableLiveData<>();
    }

    public MutableLiveData<String> getName() {
        return name;
    }

    public MutableLiveData<User> getUser() {
        return user;
    }
}

    class User {
        String account_name = "User"
    }

在Application中实现ViewModelStoreOwner

public class MyApplication extends Application implements ViewModelStoreOwner {

    @NonNull
    @Override
    public ViewModelStore getViewModelStore() {
        return viewModelStore;
    }
    private ViewModelStore viewModelStore = new ViewModelStore();
    
    // other code
}

发送全局数据更新

                MyViewModel myViewModel = new ViewModelProvider(MyApplication.getApp()).get(MyViewModel.class);
                user.account_name = new Date().toString();
                myViewModel.getUser().postValue(user);

接受全局数据更新

          MyViewModel myViewModel = new ViewModelProvider(MyApplication.getApp()).get(MyViewModel.class);
          myViewModel.getUser().observe(this, new Observer<User>() {
            @Override
            public void onChanged(User user) {
                // binding.tvBaseUrl2.setText(user.account_name); // 更新UI
            }
        });