Merge pull request #48 from PSPDFKit/simone/37-instant-document-json

Add Instant document JSON support

Author: simoarpe

README.md

@@ -216,7 +216,7 @@ adb push /path/to/your/document.pdf /sdcard/document.pdf
       url: git://github.com/PSPDFKit/pspdfkit-flutter.git
 ```
 
-4. Add a `PDFs` directory with a document in it in the root directory: `myapp/PDFs/Guide_v4.pdf` and specify it in your `pubspec.yaml`:
+4. Add a `PDFs` directory with a document in it in the root directory: `myapp/PDFs/PSPDFKit.pdf` and specify it in your `pubspec.yaml`:
 
 ```yaml
   assets:
@@ -264,7 +264,7 @@ import 'package:flutter/services.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:pspdfkit_flutter/pspdfkit.dart';
 
-const String DOCUMENT_PATH = 'PDFs/Guide_v4.pdf';
+const String DOCUMENT_PATH = 'PDFs/PSPDFKit.pdf';
 const String PSPDFKIT_FLUTTER_PLUGIN_TITLE = 'PSPDFKit Flutter Plugin example app';
 const String OPEN_DOCUMENT_BUTTON = 'Tap to Open Document';
 const String PSPDFKIT_FOR = 'PSPDFKit for';

android/src/main/java/com/pspdfkit/flutter/pspdfkit/PspdfkitPlugin.java

@@ -18,20 +18,29 @@
 import android.util.Log;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 
 import com.pspdfkit.PSPDFKit;
+import com.pspdfkit.document.PdfDocument;
+import com.pspdfkit.document.formatters.DocumentJsonFormatter;
+import com.pspdfkit.document.providers.InputStreamDataProvider;
 import com.pspdfkit.forms.ChoiceFormElement;
 import com.pspdfkit.forms.EditableButtonFormElement;
 import com.pspdfkit.forms.SignatureFormElement;
 import com.pspdfkit.forms.TextFormElement;
 import com.pspdfkit.ui.PdfActivityIntentBuilder;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
+import java.util.UUID;
 import java.util.concurrent.atomic.AtomicReference;
 
 import io.flutter.plugin.common.MethodCall;
@@ -43,6 +52,7 @@
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.schedulers.Schedulers;
 
+import static com.pspdfkit.flutter.pspdfkit.util.Preconditions.requireDocumentNotNull;
 import static com.pspdfkit.flutter.pspdfkit.util.Preconditions.requireNotNullNotEmpty;
 
 /**
@@ -76,6 +86,7 @@ public static void registerWith(Registrar registrar) {
     public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
         String fullyQualifiedName;
         FlutterPdfActivity flutterPdfActivity;
+        PdfDocument document;
 
         switch (call.method) {
             case "frameworkVersion":
@@ -128,20 +139,47 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
                 openSettings();
                 result.success(true);
                 break;
+            case "applyInstantJson":
+                String annotationsJson = call.argument("annotationsJson");
+
+                requireNotNullNotEmpty(annotationsJson, "annotationsJson");
+                document = requireDocumentNotNull(FlutterPdfActivity.getCurrentActivity(), "Pspdfkit.applyInstantJson(String)");
+
+                DocumentJsonDataProvider documentJsonDataProvider = new DocumentJsonDataProvider(annotationsJson);
+                //noinspection ResultOfMethodCallIgnored
+                DocumentJsonFormatter.importDocumentJsonAsync(document, documentJsonDataProvider)
+                        .subscribeOn(Schedulers.io())
+                        .observeOn(AndroidSchedulers.mainThread())
+                        .subscribe(
+                                () -> result.success(true),
+                                throwable -> result.error(LOG_TAG,
+                                        "Error while importing document Instant JSON",
+                                        throwable.getMessage()));
+                break;
+            case "exportInstantJson":
+                document = requireDocumentNotNull(FlutterPdfActivity.getCurrentActivity(), "Pspdfkit.exportInstantJson()");
+
+                ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+                //noinspection ResultOfMethodCallIgnored
+                DocumentJsonFormatter.exportDocumentJsonAsync(document, outputStream)
+                        .subscribeOn(Schedulers.io())
+                        .observeOn(AndroidSchedulers.mainThread())
+                        .subscribe(
+                                () -> result.success(outputStream.toString(StandardCharsets.UTF_8.name())),
+                                throwable -> result.error(LOG_TAG,
+                                        "Error while exporting document Instant JSON",
+                                        throwable.getMessage()));
+                break;
             case "setFormFieldValue":
                 String value = call.argument("value");
                 fullyQualifiedName = call.argument("fullyQualifiedName");
 
                 requireNotNullNotEmpty(value, "Value");
                 requireNotNullNotEmpty(fullyQualifiedName, "Fully qualified name");
-                flutterPdfActivity = FlutterPdfActivity.getCurrentActivity();
-                if (flutterPdfActivity == null) {
-                    throw new IllegalStateException("Before using \"Pspdfkit.setFormFieldValue()\" " +
-                            "the document needs to be presented by calling \"Pspdfkit.present()\".");
-                }
+                document = requireDocumentNotNull(FlutterPdfActivity.getCurrentActivity(), "Pspdfkit.setFormFieldValue(String)");
 
-                //noinspection ResultOfMethodCallIgnored,ConstantConditions
-                flutterPdfActivity.getPdfFragment().getDocument().getFormProvider()
+                //noinspection ResultOfMethodCallIgnored
+                document.getFormProvider()
                         .getFormElementWithNameAsync(fullyQualifiedName)
                         .subscribeOn(Schedulers.computation())
                         .observeOn(AndroidSchedulers.mainThread())
@@ -187,14 +225,10 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
                 fullyQualifiedName = call.argument("fullyQualifiedName");
 
                 requireNotNullNotEmpty(fullyQualifiedName, "Fully qualified name");
-                flutterPdfActivity = FlutterPdfActivity.getCurrentActivity();
-                if (flutterPdfActivity == null) {
-                    throw new IllegalStateException("Before using \"Pspdfkit.setFormFieldValue()\" " +
-                            "the document needs to be presented by calling \"Pspdfkit.present()\".");
-                }
+                document = requireDocumentNotNull(FlutterPdfActivity.getCurrentActivity(), "Pspdfkit.getFormFieldValue()");
 
-                //noinspection ResultOfMethodCallIgnored,ConstantConditions
-                flutterPdfActivity.getPdfFragment().getDocument().getFormProvider()
+                //noinspection ResultOfMethodCallIgnored
+                document.getFormProvider()
                         .getFormElementWithNameAsync(fullyQualifiedName)
                         .subscribeOn(Schedulers.computation())
                         .observeOn(AndroidSchedulers.mainThread())
@@ -233,13 +267,10 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
                         );
                 break;
             case "save":
-                flutterPdfActivity = FlutterPdfActivity.getCurrentActivity();
-                if (flutterPdfActivity == null) {
-                    throw new IllegalStateException("Before using \"Pspdfkit.save()\" " +
-                            "the document needs to be presented by calling \"Pspdfkit.present()\".");
-                }
-                //noinspection ResultOfMethodCallIgnored,ConstantConditions
-                flutterPdfActivity.getPdfFragment().getDocument().saveIfModifiedAsync()
+                document = requireDocumentNotNull(FlutterPdfActivity.getCurrentActivity(), "Pspdfkit.save()");
+
+                //noinspection ResultOfMethodCallIgnored
+                document.saveIfModifiedAsync()
                         .subscribeOn(Schedulers.computation())
                         .observeOn(AndroidSchedulers.mainThread())
                         .subscribe(result::success);
@@ -353,4 +384,37 @@ public boolean onRequestPermissionsResult(int requestCode, String[] permissions,
         }
         return status == 2;
     }
+
+    /** A small in-memory data provider for loading the Document instant JSON from a string. */
+    private static class DocumentJsonDataProvider extends InputStreamDataProvider {
+        @NonNull private final byte[] annotationsJsonBytes;
+        @NonNull private final UUID uuid;
+
+        DocumentJsonDataProvider(@NonNull final String annotationsJson) {
+            this.annotationsJsonBytes = annotationsJson.getBytes(StandardCharsets.UTF_8);
+            this.uuid = UUID.nameUUIDFromBytes(annotationsJsonBytes);
+        }
+        @NonNull
+        @Override
+        protected InputStream openInputStream() {
+            return new ByteArrayInputStream(annotationsJsonBytes);
+        }
+
+        @Override
+        public long getSize() {
+            return annotationsJsonBytes.length;
+        }
+
+        @NonNull
+        @Override
+        public String getUid() {
+            return String.format("document-instant-json-%s", uuid.toString());
+        }
+
+        @Nullable
+        @Override
+        public String getTitle() {
+            return null;
+        }
+    }
 }

android/src/main/java/com/pspdfkit/flutter/pspdfkit/util/Preconditions.java

@@ -8,17 +8,57 @@
  */
 package com.pspdfkit.flutter.pspdfkit.util;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
+import com.pspdfkit.document.PdfDocument;
+import com.pspdfkit.flutter.pspdfkit.FlutterPdfActivity;
+
 public class Preconditions {
     /**
      * Checks that the given <code>string</code> is not null and not empty,
      * or throws an {@link IllegalArgumentException} with the provided <code>readableName</code>.
+     *
      * @return Returns the original <code>string</code>.
      */
     public static String requireNotNullNotEmpty(@Nullable String string, @Nullable String readableName) {
-        if (string == null) throw new IllegalArgumentException(String.format("%s may not be null.", readableName));
-        if (string.isEmpty()) throw new IllegalArgumentException(String.format("%s may not be empty.", readableName));
+        if (string == null)
+            throw new IllegalArgumentException(String.format("%s may not be null.", readableName));
+        if (string.isEmpty())
+            throw new IllegalArgumentException(String.format("%s may not be empty.", readableName));
         return string;
     }
+
+    /**
+     * Checks if the given assertion is satisfied (evaluates to true) and if not,
+     * throws {@link IllegalStateException} with the provided message.
+     *
+     * @param stateAssertion   Assertion to check against.
+     * @param exceptionMessage Message of the {@link IllegalStateException}, in case it needs to be thrown.
+     */
+    public static void requireState(boolean stateAssertion, @Nullable String exceptionMessage) {
+        if (!stateAssertion) {
+            throw new IllegalStateException(exceptionMessage);
+        }
+    }
+
+    /**
+     * Checks that the document has been correctly presented and that the static instance of
+     * the Flutter Activity is not null.
+     *
+     * @param flutterPdfActivity Flutter Activity to check that may not be null.
+     * @param invokedMethod      Invoked method to use in the error message in case of an illegal state.
+     * @return Returns the loaded document.
+     */
+    @NonNull
+    public static PdfDocument requireDocumentNotNull(@Nullable FlutterPdfActivity flutterPdfActivity, @NonNull String invokedMethod) {
+        if (flutterPdfActivity == null) {
+            throw new IllegalStateException(String.format("Before using \"%s\" " +
+                    "the document needs to be presented by calling \"Pspdfkit.present()\".", invokedMethod));
+        }
+        requireState(flutterPdfActivity.getPdfFragment() != null, "PdfFragment may not be null.");
+        requireState(flutterPdfActivity.getPdfFragment().getDocument() != null, "PdfDocument may not be null.");
+
+        return flutterPdfActivity.getPdfFragment().getDocument();
+    }
 }

example/PDFs/Guide_v4.pdf

@@ -0,0 +1 @@
+{"annotations": [{"bbox": [18.4609375, 582.3333740234375, 431.6640625, 426.00003051757812], "blendMode": "normal", "createdAt": "2019-11-15T15:36:25Z", "creatorName": "simone", "isDrawnNaturally": false, "lineWidth": 10, "lines": {"intensities": [[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], "points": [[[271.6171875, 598], [266.93331909179688, 595.16668701171875], [259.71206665039062, 591.5833740234375], [255.27398681640625, 590.16668701171875], [248.65992736816406, 588.75], [244.59376525878906, 588.0030517578125], [239.75138854980469, 587.3333740234375], [234.60507202148438, 587.3333740234375], [229.98934936523438, 587.3333740234375], [225.3984375, 588.5908203125], [218.64601135253906, 588.75], [212.66595458984375, 588.75], [206.78047180175781, 590.16668701171875], [190.50941467285156, 591.5833740234375], [179.1796875, 593.75], [167.80718994140625, 595.16668701171875], [158.66848754882812, 596.5833740234375], [150.61857604980469, 598], [144.00840759277344, 600.125], [139.43266296386719, 600.125], [135.82032775878906, 601.54168701171875], [130.93865966796875, 604.41668701171875], [125.97789764404297, 607.9583740234375], [120.16405487060547, 609.6793212890625], [114.53083038330078, 612.2083740234375], [109.08804321289062, 614.375], [104.01295471191406, 616.29022216796875], [98.109375, 619.43707275390625], [92.337196350097656, 622.16668701171875], [87.625740051269531, 625.04168701171875], [82.543983459472656, 628.5833740234375], [77.507820129394531, 631.41668701171875], [71.68023681640625, 636.41668701171875], [68.25, 641.36651611328125], [63.281246185302734, 644.66424560546875], 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"2019-11-15T15:36:25Z", "v": 1}], "format": "https://pspdfkit.com/instant-json/v1", "pdfId": {"changing": "3llO8Q1c9h7lim6xrsd3BQ==", "permanent": "2ShIBg/xQBK0uIs748b8Ng=="}}