Pdf Viewer using Pdf.js in Sketchware pro

This post shows how to pick a pdf file and display it in WebView using Pdf.js in Sketchware project.

1. Create a new project in Sketchware pro. In main.xml add a TextView textview1 with text 'OPEN PDF' and a WebView pdfWebView.

2. Switch On AppCompat and design.

3. Download pdf.js from following link:
or

4. Extract the contents of the downloaded zip file.

5. In Sketchware pro project, in Asset Manager, add a sample pdf file and rename it as sample.pdf. Also, create a new folder pdfjs.



6. In pdfjs folder import all the contents extracted from the downloaded zip file.

7. Add a File picker component fp with mime type application/pdf.

8. In onCreate event, get WebView settings and enable JavaScript, and file access. Load sample.pdf in the WebView.
        WebSettings settings = binding.pdfWebView.getSettings();
settings.setJavaScriptEnabled(true);
settings.setAllowFileAccess(true);
settings.setAllowFileAccessFromFileURLs(true);
settings.setAllowUniversalAccessFromFileURLs(true);

// Load the viewer.html and point it to your local PDF file
String pdfPath = "file:///android_asset/sample.pdf";
String viewerUrl = "file:///android_asset/pdfjs/web/viewer.html?file=" + pdfPath;

binding.pdfWebView.loadUrl(viewerUrl);

9. In textview1 onClick event, use block FilePicker fp pick files.

10. In FilePicker onFilesPicked event, copy the picked file to cache of app, and then load the file from cache into WebView.

Uri uri = null;

if (_data != null) {
    if (_data.getClipData() != null) {
        // If multiple files selected, use the first one
        ClipData.Item item = _data.getClipData().getItemAt(0);
        uri = item.getUri();
    } else {
        // Single file selected
        uri = _data.getData();
    }
}

if (uri == null) {
    Toast.makeText(this, "No file selected.", Toast.LENGTH_SHORT).show();
    return;
}

File tempFile = new File(getCacheDir(), "temp.pdf");
InputStream in = null;
OutputStream out = null;

try {
    in = getContentResolver().openInputStream(uri);
    if (in == null) {
        throw new IOException("Failed to open input stream for: " + uri);
    }

    out = new FileOutputStream(tempFile);
    byte[] buf = new byte[4096];
    int len;
    while ((len = in.read(buf)) > 0) {
        out.write(buf, 0, len);
    }
    out.flush();

    String viewerUrl = "file:///android_asset/pdfjs/web/viewer.html?file=" +
            "file://" + tempFile.getAbsolutePath();

    binding.pdfWebView.loadUrl(viewerUrl);

} catch (IOException e) {
    e.printStackTrace();
    Toast.makeText(this, "Error loading PDF: " + e.getMessage(), Toast.LENGTH_LONG).show();
} finally {
    try {
        if (in != null) in.close();
        if (out != null) out.close();
    } catch (IOException ignored) { }
}


11. Save and run the project.

12. To handle errors when WebView fails to load the pdf:
a) In Asset Manager, create a new file error.html and put your custom html error page in it. Below is an example.


<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Error Loading PDF</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            padding: 20px;
            color: #333;
        }
        
        .error-container {
            max-width: 600px;
            width: 100%;
            background-color: white;
            border-radius: 12px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            padding: 40px;
            text-align: center;
            position: relative;
            overflow: hidden;
        }
        
        .error-container::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 6px;
            background: linear-gradient(90deg, #ff6b6b, #4ecdc4, #45b7d1);
        }
        
        .error-icon {
            font-size: 80px;
            margin-bottom: 20px;
            color: #ff6b6b;
        }
        
        h1 {
            font-size: 28px;
            margin-bottom: 15px;
            color: #2c3e50;
        }
        
        .error-message {
            font-size: 18px;
            line-height: 1.6;
            margin-bottom: 25px;
            color: #555;
        }
        
        .error-details {
            background-color: #f8f9fa;
            border-left: 4px solid #4ecdc4;
            padding: 15px;
            margin: 25px 0;
            text-align: left;
            border-radius: 0 8px 8px 0;
        }
        
        .error-details h3 {
            margin-bottom: 10px;
            color: #2c3e50;
        }
        
        .error-details ul {
            padding-left: 20px;
        }
        
        .error-details li {
            margin-bottom: 8px;
        }
        
        .action-buttons {
            display: flex;
            flex-wrap: wrap;
            gap: 15px;
            justify-content: center;
            margin-top: 30px;
        }
        
        .btn {
            padding: 12px 24px;
            border: none;
            border-radius: 6px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
        }
        
        .btn-primary {
            background-color: #4ecdc4;
            color: white;
        }
        
        .btn-primary:hover {
            background-color: #3db8af;
            transform: translateY(-2px);
        }
        
        .btn-secondary {
            background-color: #f8f9fa;
            color: #495057;
            border: 1px solid #dee2e6;
        }
        
        .btn-secondary:hover {
            background-color: #e9ecef;
            transform: translateY(-2px);
        }
        
        .btn-icon {
            font-size: 18px;
        }
        
        .contact-support {
            margin-top: 30px;
            font-size: 14px;
            color: #6c757d;
        }
        
        .contact-support a {
            color: #4ecdc4;
            text-decoration: none;
        }
        
        .contact-support a:hover {
            text-decoration: underline;
        }
        
        @media (max-width: 600px) {
            .error-container {
                padding: 30px 20px;
            }
            
            .action-buttons {
                flex-direction: column;
            }
            
            .btn {
                width: 100%;
            }
        }
    </style>
</head>
<body>
    <div class="error-container">
        <div class="error-icon">📄❌</div>
        <h1>We're having trouble loading this PDF</h1>
        
        <div class="error-message">
            The PDF file you're trying to access cannot be loaded. This might be due to one of the following reasons:
        </div>
        
        <div class="error-details">
            <h3>Possible causes:</h3>
            <ul>
                <li>The file has been moved or deleted</li>
                <li>There's a network connectivity issue</li>
                <li>The file is corrupted or in an unsupported format</li>
                <li>Your browser doesn't support PDF viewing</li>
            </ul>
        </div>
        
        <div class="action-buttons">
            <button class="btn btn-primary" onclick="window.location.reload()">
                <span class="btn-icon">🔄</span> Try Again
            </button>
            <button class="btn btn-secondary" onclick="history.back()">
                <span class="btn-icon">⬅️</span> Go Back
            </button>
            <button class="btn btn-secondary" onclick="goToHome()">
                <span class="btn-icon">🏠</span> Home
            </button>
        </div>
        
        <div class="contact-support">
            If the problem persists, please <a href="mailto:sanjeevk4571@gmail.com">contact our support team</a>.
        </div>
    </div>

    <script>
        function goToHome() {
            // Load the PDF viewer with sample.pdf
            window.location.href = "file:///android_asset/pdfjs/web/viewer.html?file=" + "file:///android_asset/sample.pdf";
        }
        
        // You can customize the error message based on the specific error
        function setErrorMessage(errorType) {
            const titleElement = document.querySelector('h1');
            const messageElement = document.querySelector('.error-message');
            
            if (errorType === 'not-found') {
                titleElement.textContent = "PDF File Not Found";
                messageElement.textContent = "The PDF file you're looking for doesn't exist or has been moved. Please check the URL or contact the document owner.";
            } else if (errorType === 'loading-error') {
                titleElement.textContent = "Error Loading PDF";
                messageElement.textContent = "We encountered an error while trying to load the PDF file. This might be due to a network issue or file corruption.";
            }
            // Default message is already set in HTML
        }
    </script>
</body>
</html>

b) In onCreate event, set a new WebViewClient to handle the error.

binding.pdfWebView.setWebViewClient(new WebViewClient() {
    @Override
	public void onPageStarted(WebView _param1, String _param2, Bitmap _param3) {
		final String _url = _param2;
		super.onPageStarted(_param1, _param2, _param3);
	}
			
	@Override
	public void onPageFinished(WebView _param1, String _param2) {
		final String _url = _param2;
		super.onPageFinished(_param1, _param2);
	}
			
	@Override
	public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
		super.onReceivedError(view, request, error);
		Toast.makeText(view.getContext(), "Failed to load PDF: " + error.getDescription(), Toast.LENGTH_LONG).show();
				
		view.loadUrl("file:///android_asset/error.html");
	}
});

13. To hide toolbar and sidebar in pdf Viewer, put following codes in pdfjs/web/viewer.css file.

div.toolbar {
  display: none !important;
}
#viewerContainer {
  top: 0 !important; /* Adjust if needed to remove top margin */
}
#sidebarContainer {
  display: none !important;
}
#mainContainer {
  left: 0;
}




Comments

Post a Comment

Popular posts from this blog

Simple car racing android game in Sketchware

Image
To create a simple car racing game in sketchware follow the steps given below. 1. Create a new project in Sketchware. 2. In VIEW area of main.xml add a TextView textview3 for displaying score of previous game, a TextView textview4 for displaying high score, and a Button button1 for starting game. 3. In MainActivity , add a Shared Preferences component sp:sp . 4. Add onStart event and put blocks to set the text of textview3 and textview4 . 5. Create a new page page2.xml . 6. On button1 click use intent to move to page2 . 7. On page2.xml add a LinearV linear1 with padding 0 and width and height MATCH_PARENT. 8. In Page2Activity , add a Shared Preferences component sp:sp . 9. Create a number variable highscore . 10. In onCreate event of Page2Activity , use blocks to set the value of number variable highscore , and use codes to create a new GameView and add it to linear1 , as shown in image below. The code used in the add source directly bloc...
Read more

How to enable upload from webview in Sketchware?

Image
Now that Sketchware has a block to add java code directly in the project, it is possible to enable file upload in webview. To enable file upload in webview in sketchware app, follow the steps given below. 1. Insert a webview in VIEW area in the sketchware project. Note the ID of webview, usually it is webview1 . 2. In LOGIC area of project, in onCreate event, add the block add source directly and copy the following code in it: webview1.setWebChromeClient(new WebChromeClient() { // For 3.0+ Devices protected void openFileChooser(ValueCallback uploadMsg, String acceptType) { mUploadMessage = uploadMsg; Intent i = new Intent(Intent.ACTION_GET_CONTENT); i.addCategory(Intent.CATEGORY_OPENABLE); i.setType("image/*"); startActivityForResult(Intent.createChooser(i, "File Browser"), FILECHOOSER_RESULTCODE); } // For Lollipop 5.0+ Devices public boolean onShowFileChooser(WebView mWebView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChoose...
Read more

Simple Audio recorder app in Sketchware

Image
1.  Switch on AppCompat and Design. 2. In main.xml,  add two Buttons startBtn and stopBtn , and add two TextViews textview_message and textview_file . 3. Add a SpeechToText component (To add record audio permissions). 4. Add a String variable outputFile and add a custom variable of type MediaRecorder with name mediaRecorder . 5. In onCreate , add write string__to file path__ block  (To add read and write external storage permissions). Then put following codes to define outputFile. stopBtn.setEnabled(false); File downloadsDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS); String fileName = "recording_" + System.currentTimeMillis() + ".3gp"; File file = new File(downloadsDir, fileName); outputFile = file.getAbsolutePath(); 6. Create a More block startRecording and put following codes in it. try { mediaRecorder = new MediaRecorder(); mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); ...
Read more

Retrieve contact list in Sketchware

Image
 To read contact list in Sketchware pro, follow the steps given below. 1. In the Sketchware project, in main.xml, add a ListView. Also add a custom view for ListView items. For the ListView, select the custom view. 2. Switch on AppCompat and design. 3. In permission manager, select android.permission.READ_CONTACTS . 4. In Activity, add Import event. Put following codes in the import event: import android.Manifest; import android.content.pm.PackageManager; import android.database.Cursor; import android.provider.ContactsContract; import androidx.core.app.ActivityCompat; import androidx.core.content.ContextCompat; 5. Create a more block getAllContacts of type List Map. In this more block, put following codes: ArrayList<HashMap<String, Object>> contactList = new ArrayList<>(); ContentResolver contentResolver = MainActivity.this.getContentResolver(); Cursor cursor = contentResolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, ...
Read more

Custom dialog box in Sketchware using CustomView

Image
The CustomView can be used to create a custom dialog box in Sketchware, by using simple codes. Follow the steps below to create a custom dialog pop-up. 1. In VIEW area of your project add a new CustomView . In the image above I have added a new CustomView 'cust.xml'. 2. Design the CustomView the way you want your custom dialog box to look like. In the image above, I have added an ImageView, two TextViews, and two Buttons (namely 'button1' and 'button2'). 3. Choose the event on which you want to show the dialog. It can be onBackPressed or onButtonClick, etc. 4. On the event when dialog is to be shown, use add source directly block to create and show the dialog box. In the image above I have added the code to onBackPressed event. The code used is explained below. a) First use the code to create a dialog. final AlertDialog dialog2 = new AlertDialog.Builder( MainActivity .this).create(); Note that here 'MainActivity' is the nam...
Read more