本文主要是介绍第二次启动android app的过程分析，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
网上关于在Launcher上第一次启动app的过程分析已经很多了，今天吃饭的时候在思考一个问题：我在Launcher上打开淘宝，切换到购物车，按Home键回到Launcher，再次点开淘宝的时候仍然是购物车页面。按说Launcher每次点开app都是启动同一个activity（ACTION_MAIN , CATEGORY_LAUNCHER），那么这步转换是在哪里完成的呢？
回来翻了翻代码，找到了答案：（有点长，后面会一步一步分析）
final int startActivityUncheckedLocked(final ActivityRecord r, ActivityRecord sourceRecord,IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor, int startFlags,boolean doResume, Bundle options, TaskRecord inTask) {... ...boolean addingToTask = false;TaskRecord reuseTask = null;... ...if (((launchFlags & Intent.FLAG_ACTIVITY_NEW_TASK) != 0 &&(launchFlags & Intent.FLAG_ACTIVITY_MULTIPLE_TASK) == 0)if (inTask == null && r.resultTo == null) {ActivityRecord intentActivity = !launchSingleInstance ?findTaskLocked(r) : findActivityLocked(intent, r.info);if (intentActivity != null) {... ...if (r.task == null) {r.task = intentActivity.task;}if (intentActivity.task.intent == null) {intentActivity.task.setIntent(r);}targetStack = intentActivity.task.stack;targetStack.mLastPausedActivity = null;final ActivityStack focusStack = getFocusedStack();ActivityRecord curTop = (focusStack == null)? null : focusStack.topRunningNonDelayedActivityLocked(notTop);boolean movedToFront = false;if (curTop != null && (curTop.task != intentActivity.task ||curTop.task != focusStack.topTask())) {r.intent.addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);if (sourceRecord == null || (sourceStack.topActivity() != null &&sourceStack.topActivity().task == sourceRecord.task)) {... ...movedHome = true;targetStack.moveTaskToFrontLocked(intentActivity.task,noAnimation, options, r.appTimeTracker, "bringingFoundTaskToFront");movedToFront = true;... ...}... ...}... ...if (!addingToTask &&am这篇关于第二次启动android app的过程分析的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
