Android 中的每一个 Activity 都是一个进程，或者一个应用程序就是一个进程 [英] Every Activity in Android is a Process,or One Application is one process

问题描述

在此页面中，http://androidapps.org.ua/androidintro_ipc.html，活动之间的意图切换被描述为进程间通信.现在我很困惑是每个活动都是 android 中的一个单独进程，还是应用程序内的所有活动都是一个进程.我已经使用以下方法检查了我的应用程序中所有活动和服务的进程 ID:

In this page, http://androidapps.org.ua/androidintro_ipc.html , intent switching between activities is described as Inter Process Communication. Now I am confused whether every activity is a separate process in android or All activities inside an application is one process. I have checked the process id of all activities and service in my Application using:

 int id = android.os.Process.myPid();
 System.out.println("Process id of Activity1 :"+id);

但它显示相同的进程ID.请回复.

But it is showing same process id. Please reply back.

推荐答案

All activities inside an application run in one process?

这取决于应用程序清单中 android:process 属性的值.

It depends on value of android:process attribute in application manifest.

如果在 manifest 中没有为 Application/Activity 标签定义属性 android:process，默认情况下所有 Activity 将在单个进程中运行(进程名称将是 manifest 中定义的包的名称)

if attribute android:process is not defined for Application/Activity tags in the manifest, by default all the activities will run in single process (process name will be name of the package defined in manifest)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.so.test" android:versionCode="1" android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Activity1">
        </activity>
        <activity android:name=".Activity2">
        </activity>
        <activity android:name=".Activity3">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

在上面的清单中，所有活动都在进程 com.so.test 中运行，adb shell 中的 ps 命令输出:

In the above manifest all activities run in process com.so.test,ps command output in adb shell:

# ps
app_39    668   33    84492  20672 ffffffff afd0c51c S com.so.test

如果为 Activity 指定了 android:process，将使用相同的用户 ID 创建新进程，并且该 Activity 在该进程中运行.

If android:process is specified for Activity new process will be created with the same userid and the activity runs in that process.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.so.test" android:versionCode="1" android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name" 
     android:process="com.so.p1">
        <activity android:name=".Activity1">
        </activity>
        <activity android:name=".Activity2" android:process="com.so.p2">
        </activity>
        <activity android:name=".Activity3" android:process="com.so.p3">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

如果清单定义如上

Activity1 runs in com.so.p1 process
Activity2 runs in com.so.p2 process
Activity3 runs in com.so.p3 process

adb shell 中的 ps 输出

ps output in adb shell

# ps
app_39    650   33    83192  20900 ffffffff afd0c51c S com.so.p1
app_39    659   33    83188  20864 ffffffff afd0c51c S com.so.p2
app_39    668   33    84492  20672 ffffffff afd0c51c S com.so.p3

如果 Activity 需要在此清单中未定义的另一个进程中运行，则两个 APK 应使用相同的证书进行签名.

If an Activity needs to be run in another process not defined in this manifest, both APKs should be signed with the same certificate.

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