In-depth understanding of Android (1) -- Understanding JNI and androidjni in Android
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1. What is JNI?
JNI is the abbreviation of Java Native Interface (called locally in Ja
Handler's understanding and use 1. Handler's understanding and use
Directory:
Basic knowledge:
1. Android process and thread model
2. Main Android UI thread (or thread security issues)
Knowledge points:
Handler Introduction
Handler Method 1: The subthread processes the transaction (working in the background). After the task is finished, the subthread sends a message through handler to notify the UI thread
[Android] an in-depth understanding of findViewById principles and an in-depth understanding of android
I used too much, but I don't know the principle. In Xutils, instead of using the findViewById annotation, I didn't understand it at the time. After learning it step by step, we found that the findViewById efficiency is very low compared to the annotation method. The process of annotation + reflection load
references. In the heap, the right side is the memory representation of the function object, the center is the pointing of the prototype attribute of the function object, and the left side is the object instance created by the function object. The function object points to the pointer of the prototype attribute and writes dog1, dog2, and dog3 correspond to three reference changes of Dog. prototype respectively. They also have a relationship with dog1, dog2, and dog3 in the stack. (Note: Functio
Deep understanding of CSS counters and deep understanding of cssDirectory [1] Create counter [2] use counter [3] Before DEMO
We are no longer familiar with counters. The list item mark in the ordered list is the counter.
Create a counter
There are two basic aspects for creating a counter: one is to reset the starting point of the counter, and the other is to increase it by a certain amount.Counter-reset
Cou
Em understanding, em understandingEm
Version: CSS1
Note:
Your understanding:
Note:
The default browser size is 16px.
The smallest font of Google Chrome is 12px.
Font-size; inherited.
Judgment steps:
[] Check whether the font size of the element is set:
Yes: So,
Boder, width, height, padding, margin, line-height"
, Are relative to the font size.
Font-size * em value = equals to the actual value.
A deep understanding of the use of dictionary keys in Python and a deep understanding of the python dictionary
Dictionary key
The value in the dictionary has no restrictions. It can be any Python object, that is, from a standard object to a user-defined object. However, the keys in the dictionary have type restrictions.(1) One key cannot correspond to multiple values.One principle must be clarified: each ke
Deep understanding of linear gradient in css3 and deep understanding of css3 gradientLinear Gradient in css3Linear gradient formula:
Background-image: linear-gradient ([
(Angle deg or acronyms, one or more gradient color key nodes (separated ));
This method is similar to a regular expression:
[]: Represents a character bit. It is generally used with "|" to select a character from;
|: Indicates "or", which m
Deep understanding of shared memory for inter-process communication and deep understanding of processes
Shared memory is the most useful communication method between processes and the fastest IPC format. It is designed to reduce the running efficiency of other communication mechanisms. The shared memory of two different processes A and B means that the same physical memory is mapped to the process address s
Deep understanding of JS prototype and prototype chain, and deep understanding of js prototype
PrototypeIt is a concept that is hard to understand in JavaScript. There are also many prototype-related attributes, the object has the prototype attribute, and the function object has the prototype attribute, the prototype object has the "constructor" attribute.
I. Initial Knowledge prototypeIn JavaScript, the Pr
A deep understanding of the signals of inter-process communication and a deep understanding of Process CommunicationSignal and Signal Source
Signal nature
A signal is a simulation of the interrupt mechanism at the software level. In principle, a process receives a signal and the processor receives an interrupt request. The signal is asynchronous. A process does not have to wait for the signal to arrive thro
A deep understanding of the display attribute and a deep understanding of the displayDirectory [1] block [2] inline [3] inline-block [4] none [5] list-item [6] run-in [7] table [8] inline- table [9] Before table-cell [10] table-caption
The display attribute is very common in web page layout, but it is often used only a few attribute values, such as block, inline-block, inline, And none. This article will de
Deep understanding of the box model, deep understanding of the ModelDirectory [1] width and height [2] padding [3] margin [4] Front of the border
All document elements generate a rectangular box, called an element box, which describes the space occupied by an element in the document layout. In addition, each box affects the position and size of other element boxes.
Width and height
In CSS, you can set an ex
Make a summary of the contents of the first chapter:The first chapter is an overview, not to do too much detail on the description, more is the ideological doubts. What are the reasons for learning a high-level computer language or specifically learning the Java language? Always keep a scientific attitude. First of all understand why, then is the engineering how to do, and finally in the theory of mastering very familiar situations, how to do better. After learning about why Java is being learn
today is my first time since Learning programming blog, write down the weekday learning, originally these days are learning the web framework but I think it is necessary to comb the previous study. After all, learning Java before is very sketchy just for the purpose of exams. So, thinking in Java is the main book to consolidate Java from the beginning. The search for gaps and better understanding. everything is an object . In C + + we know that ma
Understanding and simple implementation of Spring Aop, springaop understanding1. The Aspect-Oriented Programming mentioned in the AOP concept is actually a set of actions when processing a series of business logic. For example, to connect to the database: load the driver ----- get class -------- get the connection object ------- access the database ------ query --------- operation results for the above series of actions we regard the dotted line as a
Format:(function () {//code}) ();The first pair of parentheses of the enclosing function (function () {}) returns an unnamed function to the script, followed by a pair of empty parentheses that immediately execute the returned unnamed function, which is the parameter of the anonymous function in parentheses.(function (ARG) {alert (arg+100);}) (20);This example returns 120.Come back to see jquery plugin writing(function ($) { //Code Goes here}) (JQuery);This code is equivalent tovar A=functon ($
Recently, some good articles have been found on overseas websites, collected and sorted for your own understanding, recorded as notes, so that you can have memories in the future.ASP. NET is a very powerful platform for building Web applications. It provides great flexibility and capabilities so that it can be used to build all types of Web applications. most people are only familiar with high-level frameworks such as WebForms and WebServices. the. NE
, single-case1. Instance variable: the instance variable belongs to the class object, that is, the object instance is private and is allocated in the heap of the virtual machine.2. Verify thread security for instance variables:(1) From the program, we can see that when the singleton mode, there is a resource conflict, when not a singleton mode, there will not be a thread conflict.(2) Program operation result diagram:Figure 1:Figure 2:3, the conclusion: the instance variable is the instance objec
Last time is a note on a chat item, inside the socket is also involved in a lot. So what is a socket?The two programs on the network realize the exchange of data through a two-way communication connection, one end of this connection is called a socket.In layman's terms, I think it is a connector that connects the two. The English meaning of the socket is "hole" or "socket". He's the equivalent of that socket, connected to the communication between different virtual machines or different computer
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