How to withdraw the message from WeChat?

A promise is a promise. There is a saying in the ancients, "A promise of a thousand dollars is hard to chase." In a word, even if four good horses pull it, it's hard to chase it. You can see how much you value what you say.

However, people always say the wrong things, such as:

In order to solve the problems of the disabled, WeChat launched the "WeChat Withdraw" function in version 5.3. 1. 16, which provides the withdrawal option for messages sent within 2 minutes:

The user presses and holds the sent message (including the picture) and selects to withdraw from multiple selections.

Then the question is coming,

Why can a message be easily withdrawn?

In the Korean drama "You from the Stars", Professor wuli did not hesitate to use two "killer weapons": time travel and space stillness, in order to prevent money from seeing the subconscious confession message.

In fact, you don't have to envy Professor Du. Since we have the WeChat cash withdrawal function, every WeChat user can compete with super power and withdraw cash easily.

So, how does WeChat extract information from two mobile phones at the same time without the help of super power?

Take MobleA's sending message and message withdrawal to MobileB as an example:

When A.A.MobileA sends a message, it will generate a unique UniqueMsgID in the world on its own WeChat client and attach the UniqueMsgID to the body of the message to be sent.

B. When B.MobileB receives the message, it stores the message body and displays the message.

C. when C.MoblieA withdraws the message, MobleA knows the UniqueMsgID of each message body she has sent and which message needs to be withdrawn, and attaches the UniqueMsgID of the message to the withdrawal command.

D.Moblieb, when receiving the recall command, looks for the corresponding message body in his own database according to the UniqueMsgID in the recall command, and then displays the recall effect.

Why can WeChat only withdraw the message for 2 minutes?

The era of mobile Internet urges everyone to be in an era of asynchronous information processing. Most people will spend some time processing information. In contrast, two minutes is a little too short, and they often find it expired when they want to withdraw.

So, do we need to set a withdrawal period?

The answer is undoubtedly yes. In the dialogue between the two sides, if you don't set the exit time, there will be two kinds of harm:

A. If the withdrawal time is not set after the message is sent, it is likely that the receiver has seen some messages that have been sent for a long time. Further withdrawal by the sender will make the relationship between the two parties even more embarrassing and even cause unnecessary misunderstanding.

B. After the information is sent, if there is no limit on the withdrawal time, the sender can withdraw any historical message, which will lead to incomplete conversation context and affect the user experience.

Then why is the withdrawal time 2 minutes? Can't it be more or less?

In this regard, after analyzing big data, the WeChat product team believes that from the perspective of information recipients, 2 minutes is the average time from receiving to reading a message. The exit time is less than 2 minutes, which will maintain the integrity of the context to the greatest extent and give a stable user experience.

If it takes less than 2 minutes, the publisher may not have time to realize the information error and have missed the opportunity to withdraw it;

If it is longer than 2 minutes, the probability that the information will be read by the receiver will be greatly improved, and the sender does not need to withdraw it. In addition, withdrawing the information sent long ago will also destroy the contextual coherence and seriously affect the dialogue experience and effect.

Instead of setting a time limit, why not prompt the other party to read in the recall function?

Although 2 minutes is the average time from receiving to reading the information, we can't know when the receiver will read the sent information, which leads to the fact that the recall function is sometimes not so timely, thus falling into the famous "Schrodinger's cat" problem.