20160817

react native 中 pageA->pageB 想在pageB返回时刷新pageA的内容

方案一：
```
props传递
```
方案二：
```
DeviceEventEmitter
```

sina微博授权未安装客户端登陆出错：

android.content.ActivityNotFoundException: Unable to find explicit activity class {edu.gdut.myweibo/

com.sina.weibo.sdk.component.WeiboSdkBrowser}; have you declared this 

activity in your AndroidManifest.xml?

在Manifest.xml中注入SDK的WebBrowser

<activity
    android:name="com.sina.weibo.sdk.component.WeiboSdkBrowser"
    android:configChanges="keyboardHidden|orientation"
    android:exported="false"
    android:windowSoftInputMode="adjustResize" >
</activity>

react native 再次点击退出

onBackAndroid() {
   let routers = this.nav.getCurrentRoutes();
 if (this.nav && routers.length > 1) {
       this.nav.pop();
      return true;
}

let current = new Date().getTime();
    if (current - last > 2000) {
  last = current;
  ToastAndroid.show('再次点击退出', 1000);
  return true;
    } else {
      return false;
        }
  }