修复了有默认值时,键盘无法输入数据的问题

example/lib/pages/custom_keyboard.dart

@@ -14,7 +14,8 @@ class CustomKeyboardDemo extends StatefulWidget{
 }
 
 class CustomKeyboardDemoState extends State<CustomKeyboardDemo>{
-
+  TextEditingController textEditingController = TextEditingController(text:'test');
+  TextEditingController textEditing2Controller = TextEditingController(text:'test');
 
   @override
   Widget build(BuildContext context) {
@@ -29,12 +30,14 @@ class CustomKeyboardDemoState extends State<CustomKeyboardDemo>{
               body: ListView(
                 children: <Widget>[
                   TextField(
+                    controller: textEditingController,
                     keyboardType: TextInputType.text,
                   ),
                   Container(
                     height: 300.0,
                   ),
                   TextField(
+                    controller: textEditing2Controller,
                     decoration: InputDecoration(labelText: '演示键盘弹出后滚动'),
                     keyboardType: NumberKeyboard.inputType,
                   ),

lib/keyboards/keyboard_controller.dart

@@ -34,6 +34,22 @@ class KeyboardController extends ValueNotifier<TextEditingValue>{
     value = value.copyWith(selection: newSelection, composing: TextRange.empty);
   }
 
+  set value(TextEditingValue newValue) {
+
+    newValue = newValue.copyWith(  // 修正由于默认值导致的Bug
+      composing: TextRange(
+          start: newValue.composing.start < 0 ? 0: newValue.composing.start,
+          end: newValue.composing.end < 0 ? 0: newValue.composing.end
+      ),
+      selection: newValue.selection.copyWith(
+        baseOffset: newValue.selection.baseOffset < 0 ? 0: newValue.selection.baseOffset,
+        extentOffset: newValue.selection.extentOffset < 0 ? 0: newValue.selection.extentOffset
+      )
+    );
+
+    super.value = newValue;
+  }
+
   /// Set the [value] to empty.
   ///
   /// After calling this function, [text] will be the empty string and the

lib/keyboards/keyboard_manager.dart

@@ -169,11 +169,14 @@ class CoolKeyboard {
       }
     }
     _pageKey = null;
+    try{
+      KeyboardMediaQueryState queryState = _context
+          .ancestorStateOfType(const TypeMatcher<KeyboardMediaQueryState>())
+      as KeyboardMediaQueryState;
+      queryState.update();
+    }catch(_){
 
-    KeyboardMediaQueryState queryState = _context
-            .ancestorStateOfType(const TypeMatcher<KeyboardMediaQueryState>())
-        as KeyboardMediaQueryState;
-    queryState.update();
+    }
   }
 
   static clearKeyboard() {