自定义控件让TextView（Radiobutton）、Button的drawableLeft和drawableRight与文本一起居中显示

TextView的drawableLeft、drawableRight和drawableTop是一个常用、好用的属性，可以在文本的上下左右放置一个图片，而不使用更加复杂布局就能达到，我也常常喜欢用RadioButton的这几个属性实现很多效果，但是苦于不支持让drawbleLeft与文本一起居中，设置gravity为center也无济于事，终于有空研究了一下，这里与大家一起分享。

布局XML

 <com.assistant.expand.customview.DrawableCenterButton
                         android:gravity="left|center_vertical"
                         android:drawableLeft="@drawable/icon_erweima"
                         android:drawablePadding="5dp"
                 android:id="@+id/btn_scale"
                 android:layout_width="fill_parent"
                 android:layout_height="fill_parent"
                 android:background="@android:color/transparent"
                 android:singleLine="true"
                 android:text="扫描二维码签到"
                 android:textColor="@color/color_button2"
                 android:textSize="17sp" />

 /**
  * drawableLeft与文本一起居中显示
  *
  *
  */
 public class DrawableCenterTextView extends TextView {

     public DrawableCenterTextView(Context context, AttributeSet attrs,
             int defStyle) {
         super(context, attrs, defStyle);
     }

     public DrawableCenterTextView(Context context, AttributeSet attrs) {
         super(context, attrs);
     }

     public DrawableCenterTextView(Context context) {
         super(context);
     }

     @Override
     protected void onDraw(Canvas canvas) {
         Drawable[] drawables = getCompoundDrawables();
         if (drawables != null) {
             Drawable drawableLeft = drawables[0];
             if (drawableLeft != null) {
                 float textWidth = getPaint().measureText(getText().toString());
                 int drawablePadding = getCompoundDrawablePadding();
                 int drawableWidth = 0;
                 drawableWidth = drawableLeft.getIntrinsicWidth();
                 float bodyWidth = textWidth + drawableWidth + drawablePadding;
                 canvas.translate((getWidth() - bodyWidth) / 2, 0);
             }
         }
         super.onDraw(canvas);
     }
 }

下面是用Button的Right 例子

 /**
  * drawableRight与文本一起居中显示
  *
  *
  */
 public class DrawableCenterButton extends Button {

     public DrawableCenterButton(Context context) {
         super(context);
         // TODO Auto-generated constructor stub
     }

     public DrawableCenterButton(Context context, AttributeSet attrs,
     int defStyle) {
         super(context, attrs, defStyle);
     }

     public DrawableCenterButton(Context context, AttributeSet attrs) {
         super(context, attrs);
     }


     @Override
     protected void onDraw(Canvas canvas) {
         Drawable[] drawables = getCompoundDrawables();
         if (drawables != null) {
             Drawable drawableLeft = drawables[2];
                 if (drawableLeft != null) {

                 float textWidth = getPaint().measureText(getText().toString());
                 int drawablePadding = getCompoundDrawablePadding();
                 int drawableWidth = 0;
                 drawableWidth = drawableLeft.getIntrinsicWidth();
                 float bodyWidth = textWidth + drawableWidth + drawablePadding;
                 setPadding(0, 0, (int)(getWidth() - bodyWidth), 0);
                 canvas.translate((getWidth() - bodyWidth) / 2, 0);
             }
         }
         super.onDraw(canvas);
     }
 }