DataBinding

在gradle中添加dataBinding，开启数据绑定。

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.3"

    defaultConfig {
        applicationId "com.moyu.databinding"
        minSdkVersion 28
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"

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

public class MainActivity extends AppCompatActivity {

    MyViewModel myViewModel;
    ActivityMainBinding binding;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
//        setContentView(R.layout.activity_main);
        binding = DataBindingUtil.setContentView(this,R.layout.activity_main);

        myViewModel =  new ViewModelProvider(this).get(MyViewModel.class);
        myViewModel.getNumber().observe(this, new Observer<Integer>() {
            @Override
            public void onChanged(Integer integer) {
                binding.textView.setText(String.valueOf(integer));
            }
        });

        binding.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myViewModel.add();
            }
        });
    }
}

使用数据绑定

ActivityMainBinding binding;

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

取代了

setContentView(R.layout.activity_main);

---

android:onClick="@{()->data.add()}"

取代了

//        binding.button.setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View v) {
//                myViewModel.add();
//            }
//        });

binding.setData(myViewModel);
binding.setLifecycleOwner(this);

取代了

//观察者
//        myViewModel.getNumber().observe(this, new Observer() {
//            @Override
//            public void onChanged(Integer integer) {
//                binding.textView.setText(String.valueOf(integer));
//            }
//        });