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1. Initialize Library with ContentProvider:

In the daily development process, it is often encountered that Library needs to pass the Context parameter to complete initialization. In this case, this Context parameter is usually obtained from the onCreate method of the Application object. Therefore, many library will provide an init method to complete the call in Application Object.

Public class MyApplication extends Application {@ Override public void onCreate () {super.onCreate (); Library.init (this);}}

At this point, I believe you can see that when you rely on a third-party library, you have to write a custom Application, which is not a good user experience. Inspired by Android Debug Database, Firebase, we can create a ContentProvider in library, and then complete the necessary registration information in Manifest. When we apply Application, we will automatically initialize the ContentProvider defined in library. Now we can get context from onCreate in ContentProvider to initialize our own library.

Public class FirstProvider extends ContentProvider {@ Override public void attachInfo (Context context, ProviderInfo info) {super.attachInfo (context, info);} @ Override public boolean onCreate () {context = getContext (); / / you can initialize the code return true you need here }.} ````by the way, the order of Application and ContentProvider initialization is ````javaApplication.attachBaseContext (super before)-> Application.attachBaseContext (super after)-> ContentProvider.attachInfo (super before)-> ContentProvider.onCreate ()-> ContentProvider.attachInfo (super after)-> Application.onCreate (super before)-> Application.onCreate (super after) 2. Customize the ContentProvider initialization order:

If a business in library needs to use multiple custom ContentProvider, such as A, B, C, but the custom provider used to initialize is D, since the initialization process starts in provider D, then A, B, C must rise after D, then how to define the D-> A, B, C order? That is, how to ensure that D is initialized first.

To define the initialization order of provider, you can set the value of initOrder in Manifest (the higher the value, initialize first). If there are multiple processes in Library, you also need to set android:multiprocess, as shown below:

Thus, the values of FirstProvider,SecondProvider and initOrder of ThirdProvider are defined in Demo:

The final log information is as follows:

MyApplication: attachBaseContext 0 pid = 3725

MyApplication: attachBaseContext 1 pid = 3725

FirstProvider: attachInfo 0 com.sivan.FirstProvider

FirstProvider: onCreate pid = 3725

FirstProvider: attachInfo 1 com.sivan.FirstProvider

SecondProvider: attachInfo 0 info = com.sivan.SecondProvider

SecondProvider: onCreate pid = 3725

SecondProvider: attachInfo 1 info = com.sivan.SecondProvider

ThirdProvider: attachInfo 0 info = com.sivan.ThirdProvider

ThirdProvider: onCreate pid = 3725

ThirdProvider: attachInfo 1 info = com.sivan.ThirdProvider

MyApplication: onCreate 0 pid = 3725

MyApplication: onCreate 1 pid = 3725

You can see the initialization process: FirstProvider-> SecondProvider-> ThirdProvider

So we need to adjust the custom ContentProvider used to initialize according to android:initOrder, and make sure that D is initialized before A, B, C.

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