flowlayout add header and footer:js and android implement

doric-js/lib/src/widget/flowlayout.d.ts

@@ -8,7 +8,7 @@ export declare class FlowLayoutItem extends Stack {
 }
 export declare class FlowLayout extends Superview {
     private cachedViews;
-    allSubviews(): IterableIterator<FlowLayoutItem> | FlowLayoutItem[];
+    allSubviews(): FlowLayoutItem[];
     columnCount: number;
     columnSpace?: number;
     rowSpace?: number;
@@ -31,6 +31,8 @@ export declare class FlowLayout extends Superview {
      * Take effect only on iOS
      */
     bounces?: boolean;
+    header?: FlowLayoutItem;
+    footer?: FlowLayoutItem;
     reset(): void;
     private getItem;
     private renderBunchedItems;

doric-js/lib/src/widget/flowlayout.js

@@ -40,12 +40,17 @@ export class FlowLayout extends Superview {
         this.batchCount = 15;
     }
     allSubviews() {
+        const ret = [...this.cachedViews.values()];
         if (this.loadMoreView) {
-            return [...this.cachedViews.values(), this.loadMoreView];
+            ret.push(this.loadMoreView);
         }
-        else {
-            return this.cachedViews.values();
+        if (this.header) {
+            ret.push(this.header);
         }
+        if (this.footer) {
+            ret.push(this.footer);
+        }
+        return ret;
     }
     reset() {
         this.cachedViews.clear();
@@ -67,6 +72,12 @@ export class FlowLayout extends Superview {
         if (this.loadMoreView) {
             this.dirtyProps['loadMoreView'] = this.loadMoreView.viewId;
         }
+        if (this.header) {
+            this.dirtyProps['header'] = this.header.viewId;
+        }
+        if (this.footer) {
+            this.dirtyProps['footer'] = this.footer.viewId;
+        }
         return super.toModel();
     }
 }
@@ -122,6 +133,14 @@ __decorate([
     Property,
     __metadata("design:type", Boolean)
 ], FlowLayout.prototype, "bounces", void 0);
+__decorate([
+    Property,
+    __metadata("design:type", FlowLayoutItem)
+], FlowLayout.prototype, "header", void 0);
+__decorate([
+    Property,
+    __metadata("design:type", FlowLayoutItem)
+], FlowLayout.prototype, "footer", void 0);
 export function flowlayout(config) {
     const ret = new FlowLayout;
     for (let key in config) {