How to check that viewStub is already overpriced?

Question

I did not find any logical method for this task. Can I do this by checking if the id on the viewStub has changed to the one listed as inflatedid ?

Javacode:

  protected void plantViewTree() { // TODO Auto-generated method stub ViewStub mViewstub = (ViewStub) findViewById(R.id.viewStub00); if (mViewStub is inflated) { //do somthing }else mViewstub.inflate(); } 

Update Comments on eOutput

According to this code, toast always displays its message, which means that since mViewStub assigned to findViewById , it is never null, except that viewStub is not available in the alyout subclass. Any suggestions.?

 protected void plantViewTree() { // TODO Auto-generated method stub ViewStub mViewstub = (ViewStub) findViewById(R.id.viewStub00); if (mViewstub != null) Toast.makeText(getApplicationContext(), "view is inflated", Toast.LENGTH_LONG).show(); else mViewstub.inflate(); } 

Answer 1

We can view the source code of ViewStub , the most important is inflate() ,

  public View inflate() { final ViewParent viewParent = getParent(); if (viewParent != null && viewParent instanceof ViewGroup) { if (mLayoutResource != 0) { final ViewGroup parent = (ViewGroup) viewParent; final LayoutInflater factory; if (mInflater != null) { factory = mInflater; } else { factory = LayoutInflater.from(mContext); } final View view = factory.inflate(mLayoutResource, parent, false); if (mInflatedId != NO_ID) { view.setId(mInflatedId); } final int index = parent.indexOfChild(this); parent.removeViewInLayout(this); final ViewGroup.LayoutParams layoutParams = getLayoutParams(); if (layoutParams != null) { parent.addView(view, index, layoutParams); } else { parent.addView(view, index); } mInflatedViewRef = new WeakReference<View>(view); if (mInflateListener != null) { mInflateListener.onInflate(this, view); } return view; } else { throw new IllegalArgumentException("ViewStub must have a valid layoutResource"); } } else { throw new IllegalStateException("ViewStub must have a non-null ViewGroup viewParent"); } } 

Pay attention to this line parent.removeViewInLayout(this) , it was deleted in the layout after the inflate. So we can check if viewStub is too overpriced this way.

 if (mViewStub.getParent() != null) { mViewStub.inflate(); } else { mViewStub.setVisibility(View.VISIBLE); } 

Answer 2

note from google:

When the ViewStub becomes visible or when the inflate () function is called, the layout resource is inflated.

so you can check visibility (or even check if it is "null").

Answer 3

Calling yourViewStub.visibility(View.VISIBLE) you do not need to check whether it is inflated or not.

Answer 4

 if (mViewStub.getParent() != null) { //have not been inflated mViewStub.inflate(); } else { //already inflated } 

Answer 5

A simpler approach in Kotlin:

 if (viewStub != null) { viewStub.isVisible = true } else { // The view has been inflated already. } 

Answer 6

You can use this in Kotlin .. I know that it uses a tag (this is not cool), but it is easy to use. this is the kotlin extension function:

 fun ViewStub.doInflate(init: View.() -> Unit = {}, action: (View) -> Unit = {}) { val isInflated = (tag as? Boolean) ?: false if (!isInflated) { setOnInflateListener { _, view -> this.tag = true init.invoke(view) action.invoke(view) } this.inflate() } else { action.invoke(this.rootView) } 

}

and you can use it like this:

  myViewStub.doInflate({ //code that run with initialisation }, { //code that run if stub already inflated }) 

Answer 7

As follows from the documentation, we should not keep a long-lived link to the ViewStub and Android also allows Assigning an inflatedId to the ViewStub, which comes into existence as soon as it inflates

so that we can have a function signature such as getInflatedView(): View

 fun getInflatedView(@LayoutRes layoutId: Int): View { val stub: ViewStub? = findViewById(R.id.stubId) stub?.layoutResource = layoutId return stub?.inflate() ?: findViewById(R.id.inflatedId) } 

Answer 8

I solved this using flags . I declared the global boolean variable isInflatedBefore set initially to false

the code:

 //declaration of the variable private boolean isInflatedBefore = false ... ... ... protected void plantViewTree() { // TODO Auto-generated method stub ViewStub mViewstub = (ViewStub) findViewById(R.id.viewStub00); if (! isInflatedBefore) { isInflatedBefore = true; mViewstub.inflate(); }else { //some code }