addressed comments

Author: tinayuangao

src/lib/checkbox/checkbox.html

@@ -14,7 +14,7 @@
            (blur)="_onInputBlur()"
            (change)="_onInteractionEvent($event)"
            (click)="_onInputClick($event)">
-    <div md-ripple *ngIf="isRippleEnabled()" class="md-checkbox-ripple"
+    <div md-ripple *ngIf="!disableRipple" class="md-checkbox-ripple"
          [md-ripple-trigger]="getHostElement()"
          [md-ripple-centered]="true"
          [md-ripple-speed-factor]="0.3"

src/lib/checkbox/checkbox.spec.ts

@@ -488,14 +488,14 @@ describe('MdCheckbox', () => {
       testComponent.disableRipple = true;
       fixture.detectChanges();
 
-      expect(checkboxNativeElement.querySelectorAll('[md-ripple]').length).toBe(0,
-        'Expect no [md-ripple] in checkbox');
+      expect(checkboxNativeElement.querySelectorAll('[md-ripple]').length)
+        .toBe(0, 'Expect no [md-ripple] in checkbox');
 
       testComponent.disableRipple = false;
       fixture.detectChanges();
 
-      expect(checkboxNativeElement.querySelectorAll('[md-ripple]').length).toBe(1,
-        'Expect [md-ripple] in checkbox');
+      expect(checkboxNativeElement.querySelectorAll('[md-ripple]').length)
+        .toBe(1, 'Expect [md-ripple] in checkbox');
     }));
   });
 
@@ -612,7 +612,10 @@ class MultipleCheckboxes { }
 /** Simple test component with tabIndex */
 @Component({
   template: `
-    <md-checkbox [tabindex]="customTabIndex" [disabled]="isDisabled" [disableRipple]="disableRipple">
+    <md-checkbox 
+        [tabindex]="customTabIndex" 
+        [disabled]="isDisabled" 
+        [disableRipple]="disableRipple">
     </md-checkbox>`,
 })
 class CheckboxWithTabIndex {

src/lib/checkbox/checkbox.ts

@@ -13,7 +13,7 @@ import {
 } from '@angular/core';
 import {CommonModule} from '@angular/common';
 import {NG_VALUE_ACCESSOR, ControlValueAccessor} from '@angular/forms';
-import {BooleanFieldValue, MdRippleModule} from '../core';
+import {MdRippleModule, coerceBooleanProperty} from '../core';
 
 /**
  * Monotonically increasing integer used to auto-generate unique ids for checkbox components.
@@ -90,15 +90,24 @@ export class MdCheckbox implements ControlValueAccessor {
   @Input() id: string = `md-checkbox-${++nextId}`;
 
   /** Whether the ripple effect on click should be disabled. */
-  @Input() @BooleanFieldValue() disableRipple: boolean = false;
+  private _disableRipple: boolean = false;
+
+  @Input()
+  get disableRipple() { return this._disableRipple; }
+  set disableRipple(v) { this._disableRipple = coerceBooleanProperty(v); }
 
   /** ID to be applied to the `input` element */
   get inputId(): string {
     return `input-${this.id}`;
   }
 
   /** Whether the checkbox is required or not. */
-  @Input() @BooleanFieldValue() required: boolean = false;
+  private _required: boolean;
+
+  /** Whether the checkbox is required or not. */
+  @Input()
+  get required(): boolean { return this._required; }
+  set required(value) { this._required = coerceBooleanProperty(value); }
 
   /** Whether or not the checkbox should come before or after the label. */
   @Input() align: 'start' | 'end' = 'start';
@@ -341,10 +350,6 @@ export class MdCheckbox implements ControlValueAccessor {
   getHostElement() {
     return this._elementRef.nativeElement;
   }
-
-  isRippleEnabled() {
-    return !this.disableRipple;
-  }
 }