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preface Transaction is one or more database operations that need to ensure atomicity, isolation, consistency and persistence at the same time This article will explain the implementation methods of two transactions in springBoot, programming transaction configuration and declarative transaction configuration, as well as aspect transactions. O ...

We are most familiar with HTTP when learning network programming. Well, let's start with HTTP. First of all, we must understand the basic principles and actions of HTTP. Mastering the working principle of HTTP to a certain extent is very helpful for our following learning.1: Working mode    ① : establish a reliable TCP connection be ...

Previous results: There are two problems in this project: 1. State when ImageView uses mixed images_ The checked attribute setSelected(true) is invalid in the code. The specific reason is not found So I used state_ This attribute is replaced by pressed However, there was another problem. Pressing the button would change color. After releasi ...

prefaceFor Android development, after working for a few years, we have to advance or change careers directly. If you are still working on Android and want to improve your understanding of the Framework, it is an essential process. Let's start today's topic.As we know, for any programming language, the entry is generally the main function.Where ...

Custom viewgroups can be divided into three categories according to their parent classes: inherited from ViewGroup, inherited from system specific ViewGroup (such as LinearLayout) and inherited from View. The second is the simplest and the third is the most complex. Let's focus on the first case with moderate difficulty. target Follow ViewPag ...

Android Bluetooth framework 1, scan in Settings interface Enter the android setting interface and open Bluetooth, and the scanning will start automatically. Let's start with the android Bluetooth setting interface: Bluetooth switch button BluetoothSettings.java (packages\apps\settings\src\com\android\settings\blue ...

Before reading this article, it is recommended to read it first Android event distribution mechanism (1) - source code analysis_ z936689039 blog - CSDN blog 1. Case 1 We have to use the ps summary found in ViewGroup: 1. When ACTION_MOVE and action_ When the up event arrives, if no child element handles the event (mFirstTouchTarget==null), ...

1, IOC Simple Science PopularizationIOC is the Inversion of Control (IOC)If you need to use many member variables F1 and F2 in a class A.Traditional writing: if you want to use these member variables, you can use new F1(), new F2(), etc.The IOC principle is: No! We don't want new. In this way, the coupling is too high. Once the construction met ...

1, IOC Simple Science Popularization IOC is the Inversion of Control (IOC) If you need to use many member variables F1 and F2 in a class A. Traditional writing: if you want to use these member variables, you can use new F1(), new F2(), etc. The IOC principle is: No! We don't want new. In this way, the coupling is too high. Once the construction ...

1, Message prompt box and dialog box 1. Use Toast to display the message prompt box There are contacts before the message prompt box. The main application is Toast.makeText().show Next, learn in detail The objects of the Toast class have the following common methods setDuration(int duration) sets the duration toast.length of the message_ ...