diff --git a/app/src/main/java/qdx/indexbarlayout/IndexBar.java b/app/src/main/java/qdx/indexbarlayout/IndexBar.java
index 5625a08..c96fd06 100644
--- a/app/src/main/java/qdx/indexbarlayout/IndexBar.java
+++ b/app/src/main/java/qdx/indexbarlayout/IndexBar.java
@@ -4,7 +4,10 @@
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
+import android.graphics.RectF;
+import android.support.annotation.ColorInt;
 import android.support.annotation.Nullable;
+import android.support.v4.content.ContextCompat;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.View;
@@ -13,7 +16,8 @@
 
 
 public class IndexBar extends View {
-    private Paint mPaint;
+    private final String TAG = "qdx";
+    private Paint mPaint, mBarBgPaint;
     private int textSpan;//每个index占据空间
     private IndexChangeListener listener;
     private List<String> indexsList;
@@ -22,6 +26,13 @@ public class IndexBar extends View {
     private int norTextColor = Color.GRAY;
     private float yAxis;//文字y轴方向的基线
 
+    private RectF mIndexBarBg;
+    //默认的背景色
+    private int norBarBgColor = ContextCompat.getColor(getContext(), android.R.color.transparent);
+    //按下时的背景色，默认为透明
+    private int selBarBgColor = ContextCompat.getColor(getContext(), android.R.color.transparent);
+    private int mIndexBarBgRadius = 0;
+
     public IndexBar(Context context) {
         this(context, null);
     }
@@ -36,6 +47,11 @@ public IndexBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr)
     }
 
     private void init() {
+        //设置背景属性
+        mBarBgPaint = new Paint();
+        mBarBgPaint.setColor(norBarBgColor);
+        mBarBgPaint.setAntiAlias(true);
+        //设置文字属性
         mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
         mPaint.setColor(norTextColor);
         mPaint.setTextSize(textSize);
@@ -52,16 +68,27 @@ protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         if (indexsList != null && indexsList.size() > 0) {
             textSpan = h / (indexsList.size() + 1);
         }
+        //背景大小
+        mIndexBarBg = new RectF(
+                0,
+                0,
+                w,
+                h
+        );
     }
 
     @Override
     protected void onDraw(Canvas canvas) {
+        //先绘制背景
+        canvas.drawRoundRect(mIndexBarBg, mIndexBarBgRadius, mIndexBarBgRadius, mBarBgPaint);
+        //再绘制文字
         if (indexsList != null && indexsList.size() > 0) {
             for (int i = 0; i < indexsList.size(); i++) {
                 canvas.drawText(indexsList.get(i), getWidth() / 2, textSpan * (i + 1) + yAxis, mPaint);
             }
         }
 
+
     }
 
     private int curPos = -1;
@@ -74,12 +101,12 @@ public boolean onTouchEvent(MotionEvent event) {
         switch (event.getAction()) {
             case MotionEvent.ACTION_DOWN:
                 mPaint.setColor(selTextColor);
+                mBarBgPaint.setColor(selBarBgColor);
                 invalidate();
             case MotionEvent.ACTION_MOVE:
                 if (event.getY() < textSpan / 2 || (event.getY() - textSpan / 2) > textSpan * indexsList.size()) {
                     return true;
                 }
-
                 int position = (int) ((event.getY() - textSpan / 2) / textSpan * 1.0f);
                 if (position >= 0 && position < indexsList.size()) {
                     ((IndexLayout) getParent()).drawCircle(event.getY(), indexsList.get(position));
@@ -92,6 +119,7 @@ public boolean onTouchEvent(MotionEvent event) {
             case MotionEvent.ACTION_UP:
                 ((IndexLayout) getParent()).dismissCircle();
                 mPaint.setColor(norTextColor);
+                mBarBgPaint.setColor(norBarBgColor);
                 invalidate();
                 break;
         }
@@ -117,12 +145,30 @@ public void setIndexTextSize(int textSize) {
         mPaint.setTextSize(textSize);
     }
 
-    public void setSelTextColor(int selTextColor) {
+    public void setSelTextColor(@ColorInt int selTextColor) {
         this.selTextColor = selTextColor;
     }
 
-    public void setNorTextColor(int norTextColor) {
+    public void setNorTextColor(@ColorInt int norTextColor) {
         this.norTextColor = norTextColor;
         mPaint.setColor(norTextColor);
     }
+
+    public int getNorBarBgColor() {
+        return norBarBgColor;
+    }
+
+    public void setNorBarBgColor(@ColorInt int norBarBgColor) {
+        this.norBarBgColor = norBarBgColor;
+        mBarBgPaint.setColor(norBarBgColor);
+    }
+
+    public int getSelBarBgColor() {
+        return selBarBgColor;
+    }
+
+    public void setSelBarBgColor(@ColorInt int selBarBgColor) {
+        this.selBarBgColor = selBarBgColor;
+
+    }
 }
diff --git a/app/src/main/java/qdx/indexbarlayout/IndexLayout.java b/app/src/main/java/qdx/indexbarlayout/IndexLayout.java
index 4b6411f..22bacd3 100644
--- a/app/src/main/java/qdx/indexbarlayout/IndexLayout.java
+++ b/app/src/main/java/qdx/indexbarlayout/IndexLayout.java
@@ -6,6 +6,7 @@
 import android.graphics.Paint;
 import android.os.Handler;
 import android.os.Message;
+import android.support.annotation.FloatRange;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.View;
@@ -227,7 +228,7 @@ public void setDrawByTouch(boolean drawByTouch) {
     /**
      * indexBar 高度占父容器的比率，默认1
      */
-    public void setIndexBarHeightRatio(float indexBarHeightRatio) {
+    public void setIndexBarHeightRatio(@FloatRange(from = 0.0f,to = 1.0f) float indexBarHeightRatio) {
         this.indexBarHeightRatio = indexBarHeightRatio;
     }
 
diff --git a/app/src/main/java/qdx/indexbarlayout/MainActivity.java b/app/src/main/java/qdx/indexbarlayout/MainActivity.java
index 2b79048..f9b329e 100644
--- a/app/src/main/java/qdx/indexbarlayout/MainActivity.java
+++ b/app/src/main/java/qdx/indexbarlayout/MainActivity.java
@@ -64,12 +64,13 @@ public void headerClick(int pos) {
                 heads.add(car.getInitial());
             }
         }
-        indexLayout.setIndexBarHeightRatio(0.9f);
+        indexLayout.setIndexBarHeightRatio(0.7f);
         indexLayout.getIndexBar().setIndexsList(heads);
-        indexLayout.setCircleTextColor(Color.RED);
-        indexLayout.setCircleRadius(200);
-        indexLayout.setCirCleTextSize(150);
+        indexLayout.setCircleTextColor(Color.WHITE);
+        indexLayout.setCircleRadius(120);
+        indexLayout.setCirCleTextSize(80);
         indexLayout.setCircleColor(ContextCompat.getColor(this, R.color.circle_bg));
+        indexLayout.getIndexBar().setSelBarBgColor(Color.parseColor("#45000000"));
         indexLayout.getIndexBar().setIndexChangeListener(new IndexBar.IndexChangeListener() {
             @Override
             public void indexChanged(String indexName) {