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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.DrawableCenterButtonandroid: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);}@Overrideprotected 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);}@Overrideprotected 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);}
}