Add statusBarBackgroundColor to DrawerLayoutAndroid to allow it to open over the status bar

Summary:The navigation drawer of most apps on android opens over the status bar, this adds an option to do so. It implements a similar API to the native DrawerLayout by adding a statusBarBackgroundColor to DrawerLayoutAndroid.

Without statusBarBackgroundColor:
![image](https://cloud.githubusercontent.com/assets/2677334/13414490/50ebcdf4-df21-11e5-974f-c6a1343c2a4e.png)

With statusBarBackgroundColor:
![image](https://cloud.githubusercontent.com/assets/2677334/13414459/1fdc4086-df21-11e5-9658-bd47bfdb925f.png)

This PR depends on the changes in #6195 to add the `StatusBar.HEIGHT` constant I just want to put it out there now to see if this looks good. To test without the other PR just change `StatusBar.HEIGHT` for `25`.

It is implemented by making the native status bar translucent and making its background color transparent so we can draw a view of the same height as the status bar under it as a child of the DrawerLayoutAndroid. Then we can draw a semi-transparent gray View inside the drawer view to make it
Closes https://github.com/facebook/react-native/pull/6218

Differential Revision: D3017444

Pulled By: bestander

fb-gh-sync-id: ca48a47a20a2feecae360a76f3e2c9bbe6a37700
fbshipit-source-id: ca48a47a20a2feecae360a76f3e2c9bbe6a37700

Examples/UIExplorer/UIExplorerApp.android.js

@@ -71,7 +71,8 @@ class UIExplorerApp extends React.Component {
           this._overrideBackPressForDrawerLayout = false;
         }}
         ref={(drawer) => { this.drawer = drawer; }}
-        renderNavigationView={this._renderDrawerContent.bind(this, onNavigate)}>
+        renderNavigationView={this._renderDrawerContent.bind(this, onNavigate)}
+        statusBarBackgroundColor="#589c90">
         {this._renderNavigation(navigationState, onNavigate)}
       </DrawerLayoutAndroid>
     );
@@ -79,15 +80,17 @@ class UIExplorerApp extends React.Component {
 
   _renderDrawerContent(onNavigate) {
     return (
-      <UIExplorerExampleList
-        list={UIExplorerList}
-        displayTitleRow={true}
-        disableSearch={true}
-        onNavigate={(action) => {
-          this.drawer && this.drawer.closeDrawer();
-          onNavigate(action);
-        }}
-      />
+      <View style={styles.drawerContentWrapper}>
+        <UIExplorerExampleList
+          list={UIExplorerList}
+          displayTitleRow={true}
+          disableSearch={true}
+          onNavigate={(action) => {
+            this.drawer && this.drawer.closeDrawer();
+            onNavigate(action);
+          }}
+        />
+      </View>
     );
   }
 
@@ -113,9 +116,6 @@ class UIExplorerApp extends React.Component {
       const ExampleComponent = UIExplorerExampleList.makeRenderable(ExampleModule);
       return (
         <View style={styles.container}>
-          <StatusBar
-            backgroundColor="#589c90"
-          />
           <ToolbarAndroid
             logo={require('image!launcher_icon')}
             navIcon={require('image!ic_menu_black_24dp')}
@@ -131,9 +131,6 @@ class UIExplorerApp extends React.Component {
     }
     return (
       <View style={styles.container}>
-        <StatusBar
-          backgroundColor="#589c90"
-        />
         <ToolbarAndroid
           logo={require('image!launcher_icon')}
           navIcon={require('image!ic_menu_black_24dp')}
@@ -181,6 +178,10 @@ const styles = StyleSheet.create({
     backgroundColor: '#E9EAED',
     height: 56,
   },
+  drawerContentWrapper: {
+    paddingTop: StatusBar.currentHeight,
+    backgroundColor: 'white',
+  },
 });
 
 AppRegistry.registerComponent('UIExplorerApp', () => UIExplorerApp);

Libraries/Components/DrawerAndroid/DrawerLayoutAndroid.android.js

@@ -10,9 +10,12 @@
  */
 'use strict';
 
+var ColorPropType = require('ColorPropType');
 var NativeMethodsMixin = require('NativeMethodsMixin');
+var Platform = require('Platform');
 var React = require('React');
 var ReactPropTypes = require('ReactPropTypes');
+var StatusBar = require('StatusBar');
 var StyleSheet = require('StyleSheet');
 var UIManager = require('UIManager');
 var View = require('View');
@@ -25,12 +28,6 @@ var requireNativeComponent = require('requireNativeComponent');
 var RK_DRAWER_REF = 'drawerlayout';
 var INNERVIEW_REF = 'innerView';
 
-var DrawerLayoutValidAttributes = {
-  drawerWidth: true,
-  drawerPosition: true,
-  drawerLockMode: true
-};
-
 var DRAWER_STATES = [
   'Idle',
   'Dragging',
@@ -132,21 +129,52 @@ var DrawerLayoutAndroid = React.createClass({
      * The navigation view that will be rendered to the side of the screen and can be pulled in.
      */
     renderNavigationView: ReactPropTypes.func.isRequired,
+
+    /**
+     * Make the drawer take the entire screen and draw the background of the
+     * status bar to allow it to open over the status bar. It will only have an
+     * effect on API 21+.
+     */
+    statusBarBackgroundColor: ColorPropType,
   },
 
   mixins: [NativeMethodsMixin],
 
+  getInitialState: function() {
+    return {statusBarBackgroundColor: undefined};
+  },
+
   getInnerViewNode: function() {
     return this.refs[INNERVIEW_REF].getInnerViewNode();
   },
 
+  componentDidMount: function() {
+    this._updateStatusBarBackground();
+  },
+
+  componentDidReceiveProps: function() {
+    this._updateStatusBarBackground();
+  },
+
   render: function() {
+    var drawStatusBar = Platform.Version >= 21 && this.props.statusBarBackgroundColor;
     var drawerViewWrapper =
       <View style={[styles.drawerSubview, {width: this.props.drawerWidth}]} collapsable={false}>
         {this.props.renderNavigationView()}
+        {drawStatusBar && <View style={styles.drawerStatusBar} />}
       </View>;
     var childrenWrapper =
       <View ref={INNERVIEW_REF} style={styles.mainSubview} collapsable={false}>
+        {drawStatusBar &&
+        <StatusBar
+          translucent
+          backgroundColor={this.state.statusBarBackgroundColor}
+        />}
+        {drawStatusBar &&
+        <View style={[
+          styles.statusBar,
+          {backgroundColor: this.props.statusBarBackgroundColor}
+        ]} />}
         {this.props.children}
       </View>;
     return (
@@ -213,6 +241,23 @@ var DrawerLayoutAndroid = React.createClass({
   _getDrawerLayoutHandle: function() {
     return React.findNodeHandle(this.refs[RK_DRAWER_REF]);
   },
+
+  // Update the StatusBar component background color one frame after creating the
+  // status bar background View to avoid a white flicker that happens because
+  // the StatusBar background becomes transparent before the status bar View
+  // from this component has rendered.
+  _updateStatusBarBackground: function() {
+    if (Platform.Version >= 21 && this.props.statusBarBackgroundColor) {
+      // Check if the value is not already transparent to avoid an extra render.
+      if (this.state.statusBarBackgroundColor !== 'transparent') {
+        requestAnimationFrame(() => {
+          this.setState({statusBarBackgroundColor: 'transparent'});
+        });
+      }
+    } else {
+      this.setState({statusBarBackgroundColor: undefined});
+    }
+  },
 });
 
 var styles = StyleSheet.create({
@@ -233,6 +278,17 @@ var styles = StyleSheet.create({
     bottom: 0,
     backgroundColor: 'white',
   },
+  statusBar: {
+    height: StatusBar.currentHeight,
+  },
+  drawerStatusBar: {
+    position: 'absolute',
+    top: 0,
+    left: 0,
+    right: 0,
+    height: StatusBar.currentHeight,
+    backgroundColor: 'rgba(0, 0, 0, 0.251)',
+  },
 });
 
 // The View that contains both the actual drawer and the main view