How to use View Stub in android

Question

I want to use ViewStub in android, so please help me. I have created

ViewStub stub = new ViewStub; View inflated = stub.inflate();  

How to use it programmatically?

Answer 1

Like the documentation says, ViewStub is a View that is inflated lazily.

You can declare a ViewStub in an XML file like this:

 <ViewStub android:id="@+id/stub"            android:inflatedId="@+id/subTree"            android:layout="@layout/mySubTree"            android:layout_width="120dip"            android:layout_height="40dip" /> 

The android:layout attribute is a reference to the View that will be inflated next to a call of inflate(). So

ViewStub stub = (ViewStub) findViewById(R.id.stub); View inflated = stub.inflate(); 

When the method inflate() is invoked the ViewStub is removed from its parent and replaced with the right View (the root view of mySubTree layout).

If you want to do this progammatically then your code should be something like:

ViewStub stub = new ViewStub(this); stub.setLayoutResource(R.layout.mySubTree); stub.inflate();  

Answer 2

Simply a ViewStub is used to increase efficiency of rendering layout. By using ViewStub, manually views can be created but not added to view hierarchy. At the runtime, can be easily inflated, while ViewStub is inflated, the content of the viewstub will be replaced the defined layout in the viewstub.

activity_main.xml we defined viewstub but not created first.

Simple example gives better understanding,

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:id="@+id/content"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:orientation="vertical" >     <Button         android:id="@+id/btn1"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="create the view stub" />      <Button         android:id="@+id/btn2"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="Hide the stub." />      <RelativeLayout         android:layout_width="fill_parent"         android:layout_height="0dp"         android:layout_weight="1" >          <ViewStub             android:id="@+id/stub_import"             android:layout_width="fill_parent"             android:layout_height="fill_parent"             android:inflatedId="@+id/content_import"             android:layout="@layout/splash" />     </RelativeLayout> </LinearLayout> 

At runtime, when we inflate, the content will be replaced with the layout defined in the viewstub.

public class MainActivity extends Activity {      Button b1 = null;     Button b2 = null;      ViewStub stub = null;     TextView tx = null;      int counter = 0;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          b1 = (Button) findViewById(R.id.btn1);         b2 = (Button) findViewById(R.id.btn2);         b1.setOnClickListener(new OnClickListener() {             @Override             public void onClick(View v) {                 if (stub == null) {                          stub = (ViewStub) findViewById(R.id.stub_import);                     View inflated = stub.inflate();                     tx = (TextView) inflated.findViewById(R.id.text1);                     tx.setText("thanks a lot my friend..");                 }               }         });          b2.setOnClickListener(new OnClickListener() {              @Override             public void onClick(View v) {                 if (stub != null) {                     stub.setVisibility(View.GONE);                 }              }         });      } 

So, Lets look at again the view hierarchy,

when we inflate the viewstub, it will be removed from the view hierarchy.