今天本来想用react-native这个库做视频，
首先我执行命令

yarn add react-native-video

然后link

react-native link react-native-video

如果link失败，就自己添加

react-native-video-.png

react-native-video-one.png

然后我运行项目，结果出错了，报错如下：

                                                                     
FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':app'.
> Could not resolve all dependencies for configuration ':app:_debugApk'.
   > A problem occurred configuring project ':react-native-video'.
      > Could not resolve all dependencies for configuration ':react-native-video:_debugPublishCopy'.
         > Could not find com.android.support:support-annotations:27.0.0.
           Searched in the following locations:
               file:/C:/Users/asus/AppData/Local/Android/sdk/extras/android/m2repository/com/android/support/support-annotation
s/27.0.0/support-annotations-27.0.0.pom
               file:/C:/Users/asus/AppData/Local/Android/sdk/extras/android/m2repository/com/android/support/support-annotation
s/27.0.0/support-annotations-27.0.0.jar
               file:/D:/RNProject/Small/android/sdk-manager/com/android/support/support-annotations/27.0.0/support-annotations-
27.0.0.jar
           Required by:
               Small:react-native-video:unspecified > com.google.android.exoplayer:extension-okhttp:2.7.3
               Small:react-native-video:unspecified > com.google.android.exoplayer:exoplayer:2.7.3 > com.google.android.exoplay
er:exoplayer-core:2.7.3
               Small:react-native-video:unspecified > com.google.android.exoplayer:exoplayer:2.7.3 > com.google.android.exoplay
er:exoplayer-dash:2.7.3
               Small:react-native-video:unspecified > com.google.android.exoplayer:exoplayer:2.7.3 > com.google.android.exoplay
er:exoplayer-hls:2.7.3
               Small:react-native-video:unspecified > com.google.android.exoplayer:exoplayer:2.7.3 > com.google.android.exoplay
er:exoplayer-smoothstreaming:2.7.3
               Small:react-native-video:unspecified > com.google.android.exoplayer:exoplayer:2.7.3 > com.google.android.exoplay
er:exoplayer-ui:2.7.3

这个问题的核心在于这句话：

Could not find com.android.support:support-annotations:27.0.0.

在github上我找到了答案：

react-native-video-five.png

于是我就开始各种百度，谷歌，终于让我找到了解决方案：
这种问题主要是两个方面：
1、Repository问题。需要在android studio上更新版本。
详情见：https://stackoverflow.com/questions/37026322/failed-to-sync-gradle-could-not-find-com-android-supportsupport-annotations23

react-native-video-three.png

2.还有一种情况就是没有加goole 依赖(哈哈，我自创的名字)
在build.grade(不是app里面那个哟)
添加：

maven {
url "https://maven.google.com"
}

react-native-video-four.png

再次运行！完美执行！搞定！