make sure multiline TextInput is scrollable within a ScrollView

Reviewed By: bestander

Differential Revision: D3668840

fbshipit-source-id: 349314588035935543944ea6a8ddcb730c3ee85e

ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactEditText.java

@@ -29,6 +29,7 @@ import android.text.style.BackgroundColorSpan;
 import android.text.style.ForegroundColorSpan;
 import android.view.Gravity;
 import android.view.KeyEvent;
+import android.view.MotionEvent;
 import android.view.View;
 import android.view.inputmethod.InputMethodManager;
 import android.widget.EditText;
@@ -95,6 +96,24 @@ public class ReactEditText extends EditText {
     mKeyListener = new InternalKeyListener();
   }
 
+  /**
+   * Make sure multiline text input can be scrolled within a ScrollView
+   */
+  @Override
+  public boolean dispatchTouchEvent(MotionEvent ev) {
+    switch (ev.getAction()) {
+      case MotionEvent.ACTION_DOWN:
+        // Disallow ScrollView to intercept touch events.
+        this.getParent().requestDisallowInterceptTouchEvent(true);
+        break;
+      case MotionEvent.ACTION_UP:
+        // Allow ScrollView to intercept touch events.
+        this.getParent().requestDisallowInterceptTouchEvent(false);
+        break;
+    }
+    return super.dispatchTouchEvent(ev);
+  }
+
   // After the text changes inside an EditText, TextView checks if a layout() has been requested.
   // If it has, it will not scroll the text to the end of the new text inserted, but wait for the
   // next layout() to be called. However, we do not perform a layout() after a requestLayout(), so