从系统启动器启动应用程序和自定义应用程序有什么区别？

Question

应用程序 A 有一个主要 activity 启动模式设置为标准，打开它。当我从系统启动器重新打开它时，一切看起来都很正常。但是如果通过另一个app B启动app A，A会重启！为什么？

我的代码：

Intent launchIntent = getPackageManager().getLaunchIntentForPackage("A's package name");
    launchIntent.setAction(Intent.ACTION_MAIN);
    launchIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    launchIntent.addCategory(Intent.CATEGORY_LAUNCHER);
    startActivity(launchIntent);

Answer 1

根据https://developer.android.com/guide/topics/manifest/activity-element.html#lmode

，activity的默认android:launchMode是Standard

来自上面的 link :

Every time there's a new intent for a "standard" activity, a new instance of the class is created to respond to that intent

所以 onCreate() 将在您启动 intent 时被调用

这是为您的应用程序准备的，对于 Android 启动器它是不同的，它使用 Tasks 即

a collection of activities that users interact with when performing a certain job

此处定义https://developer.android.com/guide/components/tasks-and-back-stack.html

这些任务保留了堆栈中活动的顺序，因此它知道先恢复哪个。

此引文回答了您关于 Android 设备主屏幕的问题：

The device Home screen is the starting place for most tasks. When the user touches an icon in the application launcher (or a shortcut on the Home screen), that application's task comes to the foreground. If no task exists for the application (the application has not been used recently), then a new task is created and the "main" activity for that application opens as the root activity in the stack.

从系统启动器启动应用程序和自定义应用程序有什么区别？

What's the different between start app from system launcher and custom application?

android

launcher

start-activity

startapp