Needn't define it in XML file?

[VomPom]

I want to use it like this?

NewtonCradleLoading newtonCradleLoading = new NewtonCradleLoading(getActivity())
newtonCradleLoading.start();

could it happen?

systemt throws an erro: Attempt to invoke virtual method 'void com.victor.loading.newton.CradleBall.startAnimation(android.view.animation.Animation)' on a null object reference

[yankai-victor]

View must be defined in xml file or add into layout by code.

[VomPom]

Yeah,I have solved it. I think it's better to encapsulate this view into dialog,so that every time we just need use in java rather in xml.

public void showLoadingDialog() {
        if (loadingDialog == null) {
            loadingDialog = new LoadingDialog(this);
        }
        loadingDialog.showLoading();
    }
    public void stopLoadingDialog() {
        if (loadingDialog != null) {
            loadingDialog.stopLoading();
        }
    }