为什么在android开发人员指南中android:authorities是这样定义的? [英] why in the android developer guide the android:authorities is defined like this?

问题描述

下面是记事本示例代码，为什么使用 android:authorities = com.google.provider.NotePad 而不使用项目包名称?到底是什么 android:authorities 要求什么?

Below is the notepad sample code, why the android:authorities = com.google.provider.NotePad instead of using the project package name? and what exactly is android:authorities asking for?

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<!-- Declare the contents of this Android application.  The namespace
     attribute brings in the Android platform namespace, and the package
     supplies a unique name for the application.  When writing your
     own application, the package name must be changed from "com.example.*"
     to come from a domain that you own or have control over. -->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.android.notepad" >

    <uses-sdk android:minSdkVersion="11" />

    <application android:icon="@drawable/app_notes"
        android:label="@string/app_name"
    >
        <provider android:name="NotePadProvider"
            android:authorities="com.google.provider.NotePad"
            android:exported="false">
            <grant-uri-permission android:pathPattern=".*" />
        </provider>

        <activity android:name="NotesList" android:label="@string/title_notes_list">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <action android:name="android.intent.action.EDIT" />
                <action android:name="android.intent.action.PICK" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="vnd.android.cursor.dir/vnd.google.note" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.GET_CONTENT" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="vnd.android.cursor.item/vnd.google.note" />
            </intent-filter>
        </activity>

        <activity android:name="NoteEditor"
            android:theme="@android:style/Theme.Holo.Light"
            android:screenOrientation="sensor"
            android:configChanges="keyboardHidden|orientation"
        >
            <!-- This filter says that we can view or edit the data of
                 a single note -->
            <intent-filter android:label="@string/resolve_edit">
                <action android:name="android.intent.action.VIEW" />
                <action android:name="android.intent.action.EDIT" />
                <action android:name="com.android.notepad.action.EDIT_NOTE" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="vnd.android.cursor.item/vnd.google.note" />
            </intent-filter>

            <!-- This filter says that we can create a new note inside
                 of a directory of notes.  The INSERT action creates an
                 empty note; the PASTE action initializes a new note from
                 the current contents of the clipboard. -->
            <intent-filter>
                <action android:name="android.intent.action.INSERT" />
                <action android:name="android.intent.action.PASTE" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="vnd.android.cursor.dir/vnd.google.note" />
            </intent-filter>

        </activity>

        <activity android:name="TitleEditor"
            android:label="@string/title_edit_title"
            android:icon="@drawable/ic_menu_edit"
            android:theme="@android:style/Theme.Holo.Dialog"
            android:windowSoftInputMode="stateVisible">
            <!-- This activity implements an alternative action that can be
                 performed on notes: editing their title.  It can be used as
                 a default operation if the user invokes this action, and is
                 available as an alternative action for any note data. -->
            <intent-filter android:label="@string/resolve_title">
                <!-- This is the action we perform.  It is a custom action we
                     define for our application, not a generic VIEW or EDIT
                     action since we are not a general note viewer/editor. -->
                <action android:name="com.android.notepad.action.EDIT_TITLE" />
                <!-- DEFAULT: execute if being directly invoked. -->
                <category android:name="android.intent.category.DEFAULT" />
                <!-- ALTERNATIVE: show as an alternative action when the user is
                     working with this type of data. -->
                <category android:name="android.intent.category.ALTERNATIVE" />
                <!-- SELECTED_ALTERNATIVE: show as an alternative action the user
                     can perform when selecting this type of data. -->
                <category android:name="android.intent.category.SELECTED_ALTERNATIVE" />
                <!-- This is the data type we operate on. -->
                <data android:mimeType="vnd.android.cursor.item/vnd.google.note" />
            </intent-filter>
        </activity>

        <activity android:name="NotesLiveFolder" android:label="@string/live_folder_name"
            android:icon="@drawable/live_folder_notes">
            <intent-filter>
                <action android:name="android.intent.action.CREATE_LIVE_FOLDER" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>

    </application>

</manifest>

推荐答案

为什么android:authorities = com.google.provider.NotePad而不使用项目包名称?

Why the android:authorities = com.google.provider.NotePad instead of using the project package name?

我猜是因为Google喜欢那样.它是提供者，来自com.google.您还可以在您的应用程序中有多个提供程序，因此仅包名可能不够.

I guess because google liked it that way. It's a provider and it's from com.google. You can also have multiple providers in your app so just the package name may not be enough.

以及android:authorities到底在问什么?

and what exactly is android:authorities asking for?

您的提供商的系统范围的唯一标识符.或更好的全球唯一性.所有提供程序都已在系统中注册，并且它们必须是唯一的，否则，第二个想要使用相同名称的应用程序将无法安装.

A system wide unique identifier for your provider. Or better worldwide unique. All providers are registered with the system and they need to be unique or the second app that wants to use the same name can't be installed.

您最后使用该字符串通过Uri之类的提供商与您的提供商进行通信

You use that string in the end to communicate with your provider via an Uri like

Uri uri = Uri.parse("content://" + "your.authoritiy.string")

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