Why the parent layout can't get the webview touchEvent even if the webView's OnTouchEvent return false?

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http://stackoverflow.com – I put a webview into a LinearLayout and outermost is a RelativeLayout.I want the webview react the touch event(for example some javascript effect),and then pass the event to RelativeLayout. RelativeLayout is the consumer.But even if the webView's OnTouchEvent return false,it's parent LinearLayout can't get the event,let alone RelativeLayout.But if i change the webview to textview it works,I'm so confused? Any Help would be greatly appreciated. Thanks! (HowTos)