渐变试标题栏

这里主要的两个控件就是 Linelayout(包裹的是搜索框部分) Scrollview(包裹的滑动整体页面)

提醒（一定要用RelativeLayout布局）

设置控件在布局最上边line.bringToFront();

好了直接上代码

第一步：自定义控件

 

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public class ObservableScrollView extends ScrollView {        public interface ScrollViewListener {            void onScrollChanged(ObservableScrollView scrollView, int x, int y,                               int oldx, int oldy);      }      private ScrollViewListener scrollViewListener = null ;        public ObservableScrollView(Context context) {          super (context);      }        public ObservableScrollView(Context context, AttributeSet attrs,                                  int defStyle) {          super (context, attrs, defStyle);      }        public ObservableScrollView(Context context, AttributeSet attrs) {          super (context, attrs);      }      public void setScrollViewListener(ScrollViewListener scrollViewListener) {          this .scrollViewListener = scrollViewListener;      }      @Override      protected void onScrollChanged( int x, int y, int oldx, int oldy) {          super .onScrollChanged(x, y, oldx, oldy);          if (scrollViewListener != null ) {              scrollViewListener.onScrollChanged( this , x, y, oldx, oldy);          }      } }

定义控件添加监听方法

 

第二步：布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <LinearLayout
        android:id="@+id/line"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginTop="5dp"
        android:background="#fcc"
        android:gravity="center_vertical"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/sao_iv"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_marginLeft="15dp"
            android:background="@drawable/a_s" />

        <LinearLayout
            android:id="@+id/sou_sou"
            android:layout_width="match_parent"
            android:layout_height="30dp"
            android:layout_marginLeft="15dp"
            android:layout_marginRight="15dp"
            android:layout_weight="1"
            android:background="@drawable/shape_search"
            android:gravity="center"
            android:orientation="vertical">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="周大福礼包大放送" />
        </LinearLayout>
        <ImageView
            android:id="@+id/msg_iv"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_alignParentRight="true"
            android:layout_marginRight="15dp"
            android:background="@drawable/my_msg_bai" />
    </LinearLayout>

    <example.com.jddome.custom.MyScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/rlv"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </android.support.v7.widget.RecyclerView>
    </example.com.jddome.custom.MyScrollView>
</RelativeLayout>

scrollview默认只有一个子空间，所以要添加一个布局进行包裹，内容自己加
第三步：Activity.class

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import android.graphics.Color; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.LinearLayout;   public class MainActivity extends AppCompatActivity {        private LinearLayout line;      private ObservableScrollView scrollView;      private int imageHeight= 300 ; //设置渐变高度，一般为导航图片高度，自己控制      @Override      protected void onCreate(Bundle savedInstanceState) {          super .onCreate(savedInstanceState);          setContentView(R.layout.activity_main);          //查找控件          line= (LinearLayout) findViewById(R.id.line);          scrollView= (ObservableScrollView) findViewById(R.id.scrollView);          //搜索框在布局最上面          line.bringToFront();          //滑动监听          scrollView.setScrollViewListener( new ObservableScrollView.ScrollViewListener() {              @Override              public void onScrollChanged(ObservableScrollView scrollView, int x, int y, int oldx, int oldy) {                  if (y <= 0 ) {                      line.setBackgroundColor(Color.argb(( int ) 0 , 227 , 29 , 26 )); //AGB由相关工具获得，或者美工提供                  } else if (y > 0 && y <= imageHeight) {                      float scale = ( float ) y / imageHeight;                      float alpha = ( 255 * scale);                      // 只是layout背景透明                      line.setBackgroundColor(Color.argb(( int ) alpha, 227 , 29 , 26 ));                  } else {                      line.setBackgroundColor(Color.argb(( int ) 255 , 227 , 29 , 26 ));                  }              }          });        }     }