Android studio таблица excel

Manipulating Excel Files in Android using the Apache POI Library

February 11, 2022

When processing data for a custom on-device model or creating your spreadsheet app, you need to know how to manipulate spreadsheet format files. In this article, we will look at creating a spreadsheet file, opening it, and performing common statistical functions in it.

We will simulate student names and scores. The process would require a lot of code and research when done from scratch since Java does not have support for Excel file formats. Luckily, we have the Apache POI library.

Apache POI is an open-source library that provides a Java API for manipulating file formats based on the Office Open XML (OOXML) and OLE2 standards from Microsoft. Apache POI releases are available under the Apache License (V2.0).

Based on the definition, we get a clue that this library can also be used to manipulate Word and PowerPoint (slide) file formats.

Apache POI has two formats for manipulating Excel (Spreadsheet) files:

• Horrible Spreadsheet Format (HSSF)
• XML Spreadsheet Format (XSSF)

HSSF is used for .xls formats while XSSF is used for .xlsx formats. We will be using XSSF in this tutorial.

NOTE: I will be using the words Excel and Spreadsheet interchangeably.

Prerequisites

• An understanding of Kotlin. A pre-exposure to working with the file system is a plus.
• A basic understanding of Excel/Spreadsheets. One should be well versed with terminologies like cells, values, workbooks, sheets, etc.
• Working with Android development environments and the general ecosystem. Though not so necessary, working knowledge of the Gradle may come in handy as we will be adding dependencies using the Gradle files.

Getting started

After creating your app, modify the app-level and project-level Gradle files as follows:

App-level build.gradle

In the dependencies section, add the following lines:

Project-level build.gradle

Add this to the repositories section:

After the build process is done, we proceed to write the logic for creating and reading the Spreadsheet files in the MainActivity class.

Storage Permissions

Don’t forget to add these permissions in your AndroidManifest file:

Creating and adding data to the Spreadsheet

To achieve this, we follow the following steps:

1. Create a Spreadsheet in the app’s directory.
2. Add a workbook to the Spreadsheet. At this step, we will also look at creating worksheets.
3. Create cells for the worksheets.
4. Add data to the cells.

1. Creating a Spreadsheet

We will use a function called createExcelFile(ourWorkbook: Workbook) . It accepts a workbook object which we will discuss in the next step. First, we get to access our app’s directory. Next, we check whether it exists. If it does not exist, we create a directory:

Thereafter, we create an Excel file named test.xlsx and write our workbook to the file using a file output stream. You can give it a name of your choice:

The full method code is as follows:

2. Adding a workbook

In this method, we create a workbook object from the XSSFWorkbook class. A worksheet named statSheet is added to the workbook. The addData() method is then called to populate the sheet with data. We will look at this function later.

The newly created workbook is returned after the method createWorkbook() finishes executing. For the worksheet creation, Apache POI’s method called createSheet() is used:

3. Creating cells for the worksheets.

Three parameters are passed in:

1. sheetRow — The row where data is added.
2. columnIndex — The column number where a value is added.
3. cellValue — The value to be added to the cell.

In the createCell() method, we create a cell at a passed-in index and add the value to it. The library’s setCellValue(value) method is used in adding values to cells.

4. Adding data to the cells

This method is quite simple. We create rows and add data to them in the worksheet passed in as a parameter:

Check out this blog which explains about adding headers and setting header styles.

Reading the Excel file and performing statistical computations

Just like creating and populating data to the Spreadsheet, we will follow these steps:

1. Retrieve the Excel file from the app’s directory.
2. Retrieve the workbook.
3. Select the worksheet we will be working on.
4. Perform statistical computations on the data.

1. Retrieving the Excel file

We use a function called getExcelFile() . In the let scope, we check if the file exists and return it if it does. The function may return null since a file may not be present. That’s why it is made nullable:

2. Retrieving the workbook

Here, we read the workbook from the loaded spreadsheet as an input stream and then return the workbook:

3. Selecting the worksheet

We use the library’s getSheetAt(position) method for this. After the selection, we return it. Since a worksheet may not be present, this method may return a null value:

Performing the statistical computations

Three basic statistical functions are done:

Let’s have a look at them:

1. Mean

We sum all the values then divide the total value by the number of students. An array from which we will get the values is passed in as a parameter:

2. Variance

Squared difference from the mean. The logic will then be subtracting each value from the mean, squaring it, and then finding an average. Therefore, our function will have two parameters, the values array and the mean:

3. Standard variation

This is the square root of the variance:

The Apache POI library also provides built-in Excel functions such as SUMIF, COUNTIF, etc. If interested, check them out here.

Output

After running the app, we should get the following output:

The Excel file will resemble the one below:

You can access the Excel file in your Device Explorer via the IDE by following these steps: View -> Tool Windows -> Device File Explorer -> data > your-package-name -> files.

The GitHub repository can be found here and the APK file here.

Conclusion

In this tutorial, We have looked at creating an Excel file, reading the file, and performing common statistical functions on the data in the file. I hope you found this article insightful. You can customize the code and do more with it. For example, you can add dynamic input, create recycler adapters for data in the Excel files, etc.

Источник

Creating/Reading an Excel file in Android.

Home > Creating/Reading an Excel file in Android.

Its easy to store records in database via android application. But what’s the use of it when we cannot get the records on a sheet of paper.

Here’s a simple and systematic solution to get your records in an excel sheet in Android.

Excel Sheet accessing through android application in very few lines of code.

To achieve this download poi-3.7.jar or later from the following reference:-

Note:- make sure its a jar file for eclipse.

Steps to achieve the target:-

1) Create a project in android “Exel_Example” and fill all the required details.

2) In AndroidManifest.xml file add “WRITE_EXTERNAL_STORAGE ” permission as we require to access the external storage for saving the Excel file.

3) Add the poi-3.7.jar (or updated version) that you have downloaded from the link provided above. Add this jar to your project’s External Jars.

For that go to your project’s properties –> click on java Buildpath –> add External Jars –> Browse the jar.

4)Create a new class named “MainActivity.java”

Here we have 2 functionality to cover.

First is to save the Excel File and other is to read the contents of the Excel File.

To save a Excel file, check out the function “saveExcelFile” below

private static boolean saveExcelFile(Context context, String fileName) < // check if available and not read only if (!isExternalStorageAvailable() || isExternalStorageReadOnly()) < Log.e(TAG, “Storage not available or read only”); return false; >boolean success = false; //New Workbook Workbook wb = new HSSFWorkbook(); Cell c = null; //Cell style for header row CellStyle cs = wb.createCellStyle(); cs.setFillForegroundColor(HSSFColor.LIME.index); cs.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND); //New Sheet Sheet sheet1 = null; sheet1 = wb.createSheet(“myOrder”); // Generate column headings Row row = sheet1.createRow(0); c = row.createCell(0); c.setCellValue(“Item Number”); c.setCellStyle(cs); c = row.createCell(1); c.setCellValue(“Quantity”); c.setCellStyle(cs); c = row.createCell(2); c.setCellValue(“Price”); c.setCellStyle(cs); sheet1.setColumnWidth(0, (15 * 500)); sheet1.setColumnWidth(1, (15 * 500)); sheet1.setColumnWidth(2, (15 * 500)); // Create a path where we will place our List of objects on external storage File file = new File(context.getExternalFilesDir(null), fileName); FileOutputStream os = null; try < os = new FileOutputStream(file); wb.write(os); Log.w(“FileUtils”, “Writing file” + file); success = true; >catch (IOException e) < Log.w(“FileUtils”, “Error writing ” + file, e); >catch (Exception e) < Log.w(“FileUtils”, “Failed to save file”, e); >finally < try < if (null != os) os.close(); >catch (Exception ex) < >> return success; >

Here we pass the file name as the parameter to the function.

Row row = sheet1.createRow(0); c = row.createCell(0); c.setCellValue(“Item Number”); c.setCellStyle(cs);

This is how we add/enter the value in the cell.

The above code will add the value “Item Number” in the 0th row and 0th column.

To read the contents of the file have a look at the function “readExcelFile” below

Each and every entry in the cell will be printed in the log.

Here is the entire code.

MainActivity.java

Create a main.xml file in “layout” folder

In this xml file, add two buttons with id’s “writeExcel” and “readExcel” representing the “WriteExel” and “ReadExcel” buttons respectively.

Once you have done with all the above steps, your application is ready to test.

Источник

programmerworld

Know all about MATLAB/ Simulink, Selenium Testing, Android apps development and much more …

How to create an Excel file from your Android App?

This video shows the steps to create an Excel file in your Android App. It uses third party library (not available as in-built APIs) from org.apache.poi.

It hard-codes the file name and sheet name in the code. However, that can be taken as an input from the user.

For the content it takes the input from the user through an Edit Text widget. Though it uses a single line edit text but same can be done using a multi-line plain text (Edit text) user input.

It creates the file in the emulator’s external storage. However, any location on the mobile device can be used to create the file.

I hope you like this video. For any questions, suggestions or appreciation please contact us at: https://programmerworld.co/contact/ or email at: programmerworld1990@gmail.com

Like this:

Hello sir, i’ve tried this code. same as you wrote, but for me its not working. on button click nothing happends. and if i use progress dialog and dismiss the progress dialog after hssfWorkbook.write(fileOutputStream);
it doesn’t dismiss. which means the code is not writing the file at all. and of course not output.
i’ve tried many more methods with jar libraries with XSSWorkbook but nothing is working for me.
i would very much appreciate if you could help me.
Thank you

Did you try to debug the code? Any error or exception is thrown?

I also hope you have implemented the required library in your gradle file. Also, have set the Onclick attribute of the button.

If all the above is done and still gives issue then please paste your code here. We will check.

Cheers
Programmer World

Wow thank you sir for replying so fast .
I’ve debug the code . The log says no such location or file name found .
But the code is trying to make new once it shouldn’t be a problem I think .
But still I changed the directory and the file name and also tired it by creating new folder for it .
Still not working.
Once again Thank you for your reply.

Then the issue is that the file path location chosen is not correct. I have used the below line in my code:

private File filePath = new File(Environment.getExternalStorageDirectory() + “/Demo.xls”);

But check whether your mobile or emulator has this path. Else use any other path which exists on your device.

I hope the above information helps.

Cheers
Programmer World

hello sir I tried to create an xls file by using your steps mentioned above but it throws an IO exception : permission denied at this line:
filePath.createNewFile();
I had given all the required permissions in the manifests and java file but still stuck .
I would be very thankful if you help me
Thank you

Please check the below:
– You have given WRITE TO EXTERNAL STORAGE (WRITE_EXTERNAL_STORAGE) permission both in Java code and Manifest file.
– In the first time usage, App would ask from user to grant this permission. Please make sure user has granted this permission to the App.
– Also, please check that the file path (folder location) exists. Different phones may have different locations. So, ensure that the path you are using in code is valid.

The above checks should help in debugging the IO (input-output) exception you are getting. If the issue still persists then please comment here.

Cheers
Programmer World

Isn’t this function Environment.getExternalStorageDirectory() is sufficient for making an excel file? i had given permissions in both java code and manifest. but it is also showing a warning that ” WRITE_EXTERNAL_STORAGE no longer provides write access when targeting Android 10+”
please help sir 😐

Hello sir , thank you for your response.
I’ve corrected that issue by putting legacy storage true in manifest file .
Thank you very much for everything

Oh, good to know this. Good that you have found another solution.

Cheers
Programmer World

Android:requestLagecyExrernalStorage = “true”
In manifest application

For Android 10 (API level 29) onwards the External Storage related permissions have changed a bit. Now, one can directly contribute to a well-defined media collections such as MediaStore.Downloads without requesting any storage-related permissions. (This is also mentioned in the android developer portal).

Alternatively, one can also write to the App specific data without requiring any Storage privilege. Use “getExternalFilesDir” API for this. An example of this can be found in my below webpage:

Источник