Data Binding "error: Cannot Find Symbol Class Models"

First, I need to acknowledge the clearly very similar but not duplicate issue here. None of the proposed solutions in that thread work. My application file structure is as follows:

Solution 1:

Okay, I realised where the "class Models does not exist" thing comes from. I don't know whether to blame my own stupidity or the stupidly nitpicky way this binding is implemented on Android. The package needed to be called models with a lower case "m", not Models. The binding auto-name-conversion thing must have thought Models was a class, not a package.

To fix the layout, the onCreate method had to be changed to

@OverrideprotectedvoidonCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    ActivityMainBindingbinding= DataBindingUtil.setContentView(this, R.layout.activity_main);
    dataModel = newDataModel();
    cycleInformationBinding.setRecommendation(dataModel);

    // set toolbarToolbartoolbar= (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    // Drawer layout settingDrawerLayoutdrawer= (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggletoggle=newActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.addDrawerListener(toggle);
    toggle.syncState();

    NavigationViewnavigationView= (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}

Specifically, things had to happen in the order:

1. setContentView to the main activity
2. Set up the data model binding
3. Layout concerns like drawer and toolbar.

Any other order would cause either the model binding to fail or the toolbar to not display correctly.

Solution 2:

Just convert your existing layouts to data binding layouts (Don't forget to add variable in your xml with your activity mentioned in type)

Example:

<variable name="navdrawer" type="com.example.sampleapp.HomeScreenActivity" />

This will generate a data binding class for NavigationHeaderView in this format(May differ) NavHeaderYourActivityName.

When you bind your parent activity, you will use that binding instance to get DrawerLayout and your NavigationView, respectively.

A sample code to reduce the boilerplate for initializing views in your code:

NavHeaderHomeScreenBindingnavHeaderHomeScreenBinding= 
DataBindingUtil.setContentView(this, R.layout.nav_header_home_screen);
AppBarHomeScreenBindingappBarHomeScreenBinding= 
DataBindingUtil.setContentView(this, R.layout.app_bar_home_screen);
ActionBarDrawerToggletoggle=newActionBarDrawerToggle(this, binding.drawerLayout, appBarHomeScreenBinding.toolbar, 
R.string.navigation_drawer_open, R.string.navigation_drawer_close);
binding.drawerLayout.addDrawerListener(toggle);
toggle.syncState();
binding.navView.setNavigationItemSelectedListener(this);

I hope this helps someone! Thank you!

Solution 3:

First try to remove redurant setContentView(R.layout.activity_main);

ActivityMainBindingbinding= DataBindingUtil.setContentView(this, R.layout.activity_main);

Second add to end of "onCreate" function

binding.included.setValues(dataModel);
binding.executePendingBindings();

if you use include than you may add to your include id for example

<include
    android:id="@+id/included"
    layout="@layout/content_main"
    app:values="@{DataModel}"/>

and use

binding.included.setValues(dataModel);

research about using databinding with included layouts