Normal and reverse value transfer between pages

Answer 1

The following are some common methods of transferring value between pages:

##1. Page Transfer in uniapp (Normal Transfer)
1. * * Jump to the method of passing parameters **
- Uniapp provides a variety of page jump methods, such as uni.navigateTo, uni.redirectTo, uni.reLaunch, uni.swickTab, uni.navigateBack, and so on. If you want to transfer the value when you jump to the page, you can find the click event and directly select the event to jump to the page. If there are expansion parameters, you can directly add the transfer parameters in the additional parameters.
- For example, when clicking on an item on a list page to enter the details page, the ID of the list item could be added as a parameters during the jump.
2. * * Receive parameters **
- In the onload function of the target page, you can get the passed data through the options argument. The tool may have already written the parameters into the global option, but because it is uncertain what the actual parameters are, it may be necessary to fill in the parameters when binding the variable.

##2. Passing values between multiple webviews in the Mui framework (examples of normal and reverse value passing)
1. * * Normal Transfer (From parent page to child page)**
- First, add a custom event in the sub-page, such as `window.addEventListener ('customEvent', function (event){//You can get the passed parameters through event.detail`.
- The parent page preloads the child page, and then you can trigger the custom event of the target window (child page) through the mui.fire () method. At this time, the data parameters are passed to the child page.
2. * * Reverse value transfer (similar idea from the child page to the parent page)**
- You can define a receiving function or event listener on the parent page. After the child page's operation is completed, the corresponding event will be triggered to pass the data back to the parent page. For example, the child page passed the data to the parent page by calling the method exposed on the window object of the parent page or triggering a custom event.

##3. Web-worker-based communication between pages (can be used for special value transfer needs)
1. * * Normal value transfer (main thread to worker thread)**
- Create a worker object in the main thread (e.g. editEmail.vue), such as `const myWorker = new Worker ('/worker.js');`, and then send a message to the worker.js thread through `myWorker. postMessage ('Greeting from main.js')`.
2. * * Reverse value transfer (worker thread to main thread)**
- In the worker.js thread, use `self.addEventListener ('message', e =>{//Receive messages console.log (w.example.com); self.postMessage (' Greeting from Worker.js');});` Receive messages from the main thread and send messages back to the main thread. In the main thread, receive messages from the worker thread through `myWorker.addEventListener ('message', e =>{console.log (web.example.com);})`.

##4. Page Transfer in Android (Normal Transfer)
1. * * Single data transfer (Take the Main Activity page and the Get Data Activity page as an example)**
- Data can be transferred from the Main Activity page to the getdataactivity page through Intent. For example, create an Intent object in the Main Activity, add data to the Intent, and then start the getdataactivity. Obtain the data from the Intent in the getdataactivity.
2. * * Multiple data transfer is similar to the expansion of single data transfer **
- It was also a method to add multiple pieces of data in a suitable form (such as bundle) to the Intent through the Intent, and then extract the data from the Intent on the target page.

For reverse value transfer, you can use methods such as startActivityForResults. For example, after the getdataactivity page processes the data, it returns the result data to the mainactivity page through the intent. The mainactivity page overwrites the onActivityresult method to receive the returned data.
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