Xamarin重写EditText，在右侧添加一个清除按钮图标

实现效果图：

实现代码：

  1  public class ClearEditView : EditText
  2     {
  3         private Drawable mRightDrawable;
  4         private bool hasFoucs;
  5         Context context;
  6         public ClearEditView(Context context) : base(context)
  7         {
  8             this.context = context;
  9             init();
 10         }
 11         public ClearEditView(Context context, IAttributeSet attrs) : base(context, attrs)
 12         {
 13             this.context = context;
 14             init();
 15         }
 16 
 17         public ClearEditView(Context context, IAttributeSet attrs, int defStyle) : base(context, attrs, defStyle)
 18         {
 19             this.context = context;
 20             init();
 21         }
 22 
 23         private void init()
 24         {
 25             //getCompoundDrawables:
 26             //Returns drawables for the left, top, right, and bottom borders.
 27             Drawable[] drawables = this.GetCompoundDrawables();
 28 
 29             //取得right位置的Drawable
 30             //即我们在布局文件中设置的android:drawableRight
 31             mRightDrawable = drawables[2];
 32             //设置焦点变化的监听
 33             this.FocusChange += new EventHandler<FocusChangeEventArgs>(FocusChangeListenerImpl);
 34 
 35             //设置EditText文字变化的监听
 36             this.TextChanged += new EventHandler<TextChangedEventArgs>(TextWatcherImpl);
 37             //初始化时让右边clean图标不可见
 38             SetClearDrawableVisible(false);
 39         }
 40         public void TextWatcherImpl(object obj, TextChangedEventArgs e)
 41         {
 42             if (hasFoucs)
 43             {
 44                 SetClearDrawableVisible(this.Text.Length > 0);
 45             }
 46         }
 47 
 48         public void FocusChangeListenerImpl(object obj, FocusChangeEventArgs e)
 49         {
 50 
 51             this.hasFoucs = e.HasFocus;
 52             if (hasFoucs)
 53             {
 54                 bool isVisible = Text.ToString().Length >= 1;
 55                 SetClearDrawableVisible(isVisible);
 56             }
 57             else
 58                 SetClearDrawableVisible(false);
 59         }
 60 
 61         /// <summary>
 62         ///当手指抬起的位置在clean的图标的区域
 63         ///我们将此视为进行清除操作
 64         ///Width:得到控件的宽度
 65         /// e.GetX():抬起时的坐标(改坐标是相对于控件本身而言的)
 66         /// TotalPaddingRight:clean的图标左边缘至控件右边缘的距离
 67         /// PaddingRight:clean的图标右边缘至控件右边缘的距离
 68         /// 于是:
 69         /// Width - TotalPaddingRight()表示:
 70         /// 控件左边到clean的图标左边缘的区域
 71         /// Width - PaddingRight()表示:
 72         /// 控件左边到clean的图标右边缘的区域
 73         /// 所以这两者之间的区域刚好是clean的图标的区域
 74         /// </summary>
 75         /// <returns></returns>
 76         public override bool OnTouchEvent(MotionEvent e)
 77         {
 78             switch (e.Action)
 79             {
 80                 case MotionEventActions.Down:
 81 
 82                     bool isClean = (e.GetX() > (Width - TotalPaddingRight)) &&
 83                                       (e.GetX() < (Width - PaddingRight));
 84                     if (isClean)
 85                     {
 86                         SetText(string.Empty, BufferType.Normal);
 87                     }
 88                     break;
 89 
 90                 default:
 91                     break;
 92             }
 93             return base.OnTouchEvent(e);
 94         }
 95 
 96         //隐藏或者显示右边clean的图标
 97         public void SetClearDrawableVisible(bool isVisible)
 98         {
 99             Drawable rightDrawable;
100             if (isVisible)
101             {
102                 rightDrawable = mRightDrawable;
103             }
104             else
105             {
106                 rightDrawable = null;
107             }
108             //使用代码设置该控件left, top, right, and bottom处的图标
109             SetCompoundDrawables(GetCompoundDrawables()[0], GetCompoundDrawables()[1],
110                                  rightDrawable, GetCompoundDrawables()[3]);
111         }
112     }
View Code

UI引用布局：

 1 <XQY.ClearEditView
 2       android:id="@+id/et_user_name"
 3         android:paddingLeft="28dip"
 4         android:layout_width="fill_parent"
 5         android:layout_height="55dip"
 6         android:hint="邮箱"
 7         android:textColorHint="#a9a9a9"
 8         android:gravity="center_vertical"
 9         android:textSize="17sp"
10         android:background="@drawable/et_radius"
11       android:drawableRight="@mipmap/delete"
12        android:paddingRight="16dip"/>
View Code

 

posted on 2016-12-01 15:43  Feel  阅读(262)  评论(0)    收藏  举报

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