View.getContext(): Returns the context the view is currently running in. Usually the currently active Activity. Activity.getApplicationContext(): Returns the context for the entire application (the process all the Activities are running inside of). Use this instead of the current Activity context if you need a context tied to the lifecycle of the entire application, not just the current Activity. ContextWrapper.getBaseContext(): If you need access to a Context from within another context, you use a ContextWrapper. The Context referred to from inside that ContextWrapper is accessed via getBaseContext().

从这个文档

我明白你应该用:

尝试使用上下文应用程序而不是上下文活动

getApplicationContext ()

它用于应用程序级别，并引用所有活动。

全文()和全文()

很可能是相同的。这些只是指当前活动是活的。

this

总是引用当前类对象。

View.getContext(): Returns the context the view is currently running in. Usually the currently active Activity. Activity.getApplicationContext(): Returns the context for the entire application (the process all the Activities are running inside of). Use this instead of the current Activity context if you need a context tied to the lifecycle of the entire application, not just the current Activity. ContextWrapper.getBaseContext(): If you need access to a Context from within another context, you use a ContextWrapper. The Context referred to from inside that ContextWrapper is accessed via getBaseContext().

getApplicationContext()——返回应用程序中运行的所有活动的上下文。

getBaseContext()—当您想要从您可以访问的应用程序中的另一个上下文访问Context时。

getContext()——它只返回当前正在运行的活动的上下文视图。

This - it's引用当前类对象

它引用当前活动类对象，而活动继承上下文，因此必须在可以使用上下文或活动的地方使用它。

“什么是Context”是Android世界中最难回答的问题之一。

上下文定义了访问系统资源、检索应用程序的静态资产、检查权限、执行UI操作等等的方法。从本质上讲，上下文是生产环境中上帝对象反模式的一个例子。

当涉及到我们应该使用哪种上下文时，它变得非常复杂，因为除了是上帝对象之外，上下文子类的层次树粗暴地违反了利斯科夫替换原则。

这篇博客文章(现在来自Wayback Machine)试图总结上下文类在不同情况下的适用性。

为了完整起见，让我从那篇文章中复制主表:

+----------------------------+-------------+----------+---------+-----------------+-------------------+ | | Application | Activity | Service | ContentProvider | BroadcastReceiver | +----------------------------+-------------+----------+---------+-----------------+-------------------+ | Show a Dialog | NO | YES | NO | NO | NO | | Start an Activity | NO¹ | YES | NO¹ | NO¹ | NO¹ | | Layout Inflation | NO² | YES | NO² | NO² | NO² | | Start a Service | YES | YES | YES | YES | YES | | Bind to a Service | YES | YES | YES | YES | NO | | Send a Broadcast | YES | YES | YES | YES | YES | | Register BroadcastReceiver | YES | YES | YES | YES | NO³ | | Load Resource Values | YES | YES | YES | YES | YES | +----------------------------+-------------+----------+---------+-----------------+-------------------+ An application CAN start an Activity from here, but it requires that a new task be created. This may fit specific use cases, but can create non-standard back stack behaviors in your application and is generally not recommended or considered good practice. This is legal, but inflation will be done with the default theme for the system on which you are running, not what’s defined in your application. Allowed if the receiver is null, which is used for obtaining the current value of a sticky broadcast, on Android 4.2 and above.