Android Webview - After Changing Scale To 1.5 It Reverting Back?

I wrote a sample application which displays some test message using webview .The Application has two activities, one activity simply contains a button, when user click on this button , it launch another activity which display the test message on a webview .

I have set setInitialScale() of webview as 150, Now the issue is like, Normally webvbiew displays the content with the scale size 150 (as I set ) but some times it displays the contents with a scale greater than 150.

I overrided the onScaleChanged() function in webViewClient.

In normal case before drawing the content on webview I am getting onScaleChanged() callback ,with the value oldscale as 2 and new scale as 1.5. When issue occurs , I am getting two onScaleChanged() callbacks before drawing the content!!! ,at first I get the onScalechange() callback with oldscale as 2 and new scale as 1.5 , after that getting another onScaleChanged() callback with oldscale as 1.5 and new scale as 2.0 and hence it draws the webview with the scale 2.0 irrespective of setInitialScale() I have given in my application.

This issue happens only in the case if I set setInitialScale() to a value less than device's default webview scale. As per my understanding ,Every device has its own default Scale for webview based on their display property like .075 for ldpi and 1.5 for hdpi etc )

In my device defaultScale for webview is 2, and I set the setInitialScale() as 1.5(150)

normaly webview reset the scale from 2 to 1.5 before draw ( That is from defult to new value ) and it works fine
But some time after changing the scale to 1.5 it reverting back to 2. and issue occurs

public class webActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
[Code].....