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This article mainly introduces "how to start Android Activity". In daily operation, I believe many people have doubts about how to start Android Activity. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts about "how to start Android Activity". Next, please follow the editor to study!

The purpose of this function is to find a task where ID is equal to the parameter taskId, and then find out if an instance of the Activity that is about to be started already exists in this task.

If they exist, the Activity above the Actvity instance up to the top of the task stack ends them by calling the finishActivityLocked function.

In this example, you want to see if there is an instance of the SubActivity type in the task where the property value affinity is equal to "shy.luo.task", and if so, end all the Activity on it.

Here, a task with an attribute value of affinity equal to "shy.luo.task" has only one MainActivity, and it is not an instance of SubActivity, so this function returns null.

Going back to the previous startActivityUncheckedLocked function, where the variable top is null, execute the following else statement:

[java] view plaincopy if (top! = null) {. } else {/ / A special case: we need to / / start the activity because it is not currently / / running, and the caller has asked to clear the / / current task to have this activity at the top. AddingToTask = true; / / Now pretend like this activity is being started / / by the top of its task, so it is put in the / / right place. SourceRecord = taskTop;}

Therefore, the value of the variable addingToTask is true, and the value of the variable sourceRecord is set to taskTop, which is the return value of the previous call to the findTaskLocked function, which in this case represents MainActivity.

Moving on, the following if statement:

[java] view plaincopy if (r.packageName! = null) {/ / If the activity being launched is the same as the one currently / / at the top, then we need to check if it should only be launched / / once. ActivityRecord top = topRunningNonDelayedActivityLocked (notTop); if (top! = null & & r.resultTo = = null) {if (top.realActivity.equals (r.realActivity)) {if (top.app! = null & & top.app.thread! = null) {. } else {. At this point, the study on "how to start Android Activity" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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