MVC for android

I believe that the job of a programmer is not to write code, but to optimize processes. We write code so that its user can quickly and efficiently achieve world domination, for example. And it would be a bit strange to optimize the work of others and not to optimize one’s own. A shoemaker without boots is irrational.

So. I recently began to write the second version of my app for the same religious fanatics like me. APP is not important, it is important that two-way binding of widgets to data is a rather routine, fraught with copyright work. It becomes especially fun if there are dependencies: If this text has changed - update one. Already on the second screen, being inspired by the Butter Knife project, I realized that there is a huge scope for generalization (and, oddly enough, I did not find anything like it).

Meet the project Bandera *
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(I copy the example code for myself)

• Specify bandera-compile.jar as a compiler annotation processor
• We describe the class of the model:
  

  public class MainActivityModel { private int catCount; public MainActivityModel(CatRecordFromDb cats) { // init your viewmodel here // ... } @BindModel({ R.id.practice_image, R.id.buttonStart }) // RO binding to imageUri for ImgView and ImgButton public String getFancyImage() { return getModel().imageUrl; } @BindModel(R.id.editNumberOfCats) // getter for EditText value initialisation public int getCatsCount() { // method name can be anything, getters just need the "get" in front return catCount; // conversion from int to String happens magically at google offices* (even offline!) } @BindModel(R.id.editNumberOfCats) // setter to update the model from the control public void setCatNumber(int catCount) { // setter name doesn't need to match getter's, just be "set<Whatever>" this.catCount = catCount; // the value is already converted into target type recalculateTotal(); // do the magic after cat count changed } } // * Measurement of correctness of this description is pending indifinitely 

  
  
• In the activity we associate the model and the presentation
  

   binder = doo.bandera.Models.Bind(this, new MainActivityModel(catsFromDb)); // doo.bandera.Models.Bind for your activity/model pair is generated during compilation 

  
  
• Well, if something has changed outside the bundle, we report this:
  

   binder.updateDirtyValues(); // scans what changed in the model and updates widgets 

  
  
• We specify bandera-runtime.jar as dependency included in apk.
• Everything is working

That is, the routine went to the library. The logic is rendered in the ViewModel (I know, this is not quite MVC, but rather MV-C). Everyone is happy.

The project is written pragmatically to fit your needs, so only TextView, EditText, DateTimePicker, ProgressBar, ImageView, ImageButton (picture) are supported so far. For events, I use the same Butter Knife.

Well, the special charm is that the binding code is generated when compiling **, that is, there are simply no traditional android fears annotations-runtime-reflection-slow-as-hell.

* Word consonant Binding and Android
** I’m not at all pleased with the way I generate this code, but for now Everything works and we will do it nicely later