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concept SEL: method name (number)IMP: a function pointer that holds the address of the method@Selector (method name) gets the number of the method, resulting in SEL type. His behavior is basically equivalent to the function pointer in C languagedifference In C language, the function name can be assigned directly to a function pointer, and the f ...

preface In a project, it is often necessary to display data at the view level immediately. Sometimes, because of asynchronous data transfer, the page will not be displayed immediately on the page. In this case, you need to use the nextTick method provided by Vue. The main reason is that Vue's data vi ...

130.blob to file  /**     *  @param { blob } blob     *  @param { string } fileName        */    export const blobToFile = (blob, fileName) => {     blob.lastModifiedDate = new Date();     blob.name = fileName;     return blob;     }; 131.file to base64  /**     * @param { * } file Picture file       ...

2020.6.13 This paper borrows @ hyfhaha's idea of problem solving. The day before yesterday, I went back to school to see my teacher. They were all the same. They didn't change at all. The teacher was also very happy to see us. He left us to study at night and then let us go. A-Level class asked cs about ...

The beginning of 2020 is extraordinary. I will stay at home and study io again io is divided into bio,nio,aio Among them, netty belongs to nio, and aio has not been widely used, so it has great potential in the future Understand several concepts Synchronous and asynchronous Blocking and non blockingio m ...

Guide reading for Lao Meng: how to click the Back button twice to exit the App, how to realize multiple routes in the App, and how to realize the Back button only to exit the specified page will be shown in this article. WillPopScope WillPopScope is used to process whether to leave the current page or not. There are many ways to leave the cu ...

What is nextTick Vue's official document says, "perform a delayed callback after the next DOM update cycle. Use this method immediately after modifying the data to get the updated dom. " , why does such an API appear? The main reason is that Vue uses asynchronous execution to update dom. As long as it listens for data changes, Vue wi ...

Background: for a recent countdown learning time recording project, you need to record the progress of the current page when the user clicks the back button of the browser or directly closes the browser, or directly exits wechat or enters the background. The next time you go in, you need to start the countdown from the last place you left. At f ...

Today I'm talking with you about Python and Nose's automatic testing of mobile applications. I hope it can help you. There's something bad to say. Please give me more advice! The coolest thing about automated functional testing with Appium is that you can write your test code in any language that has the best testing tools for you. Python is t ...

When we use https to make network requests, we will receive the certificates from the server. These certificates are divided into agency certificates and certificates issued by ourselves. In ios, if we are going to request an organization certified to send an https request, we don't need to process it. But if it is a self signed certificate, we ...