修复bug

Author: lialzm

Diff for: toolbartest/src/main/java/com/lialzm/baidu/toolbartest/MainActivity.java

@@ -9,15 +9,12 @@
 import android.widget.ArrayAdapter;
 import android.widget.ListView;
 
-import com.lialzm.hyb.toolbartest.R;
-
 import java.util.ArrayList;
 import java.util.List;
 
 public class MainActivity extends AppCompatActivity {
 
     private ListView lv;
-    //测量值
     private float headerHeight;//顶部高度
 
     @Override
@@ -39,6 +36,7 @@ protected void onCreate(Bundle savedInstanceState) {
             list.add("item" + i);
         }
         headerHeight = dp2px(200);
+
         lv.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1, list));
         lv.setOnScrollListener(new AbsListView.OnScrollListener() {
             @Override
@@ -49,7 +47,7 @@ public void onScrollStateChanged(AbsListView view, int scrollState) {
             @Override
             public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                 float scrollY = getScrollY(view);
-                float offset = 1 - Math.max((headerHeight - scrollY) / headerHeight, 0f);
+                float offset = 1 - Math.max((headerHeight - toolbar.getHeight() - scrollY) / (headerHeight - toolbar.getHeight()), 0f);
                 toolbar.getBackground().setAlpha((int) (offset * 255));
 
             }
@@ -63,7 +61,6 @@ private int dp2px(int dpVal) {
     }
 
 
-
     /**
      * 得到ListView在Y轴上的偏移
      */

Diff for: toolbartest/src/main/res/layout/activity_main.xml

@@ -1,10 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical">
 
+
+    <ListView
+        android:id="@+id/lv"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+    </ListView>
+
     <android.support.v7.widget.Toolbar
         android:id="@+id/tb_main"
         android:layout_width="match_parent"
@@ -14,12 +22,4 @@
         app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />
 
 
-    <ListView
-        android:id="@+id/lv"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent">
-
-
-    </ListView>
-
-</LinearLayout>
+</FrameLayout>