Add unified API for inserting rich content (e.g. pasting an image)

The new callback provides a single API that apps can implement to
support the different ways in which rich content may be inserted.

The API is added to TextView and unifies the following code paths:
* paste from the clipboard (TextView.paste)
* content insertion from the IME (InputConnection.commitContent)
* drag and drop (Editor.onDrop)
* autofill (TextView.autofill)

Corresponding API in support lib: aosp/1200800

Bug: 152068298
Test: Manual and unit tests
  atest FrameworksCoreTests:TextViewRichContentReceiverTest
  atest FrameworksCoreTests:AutofillValueTest
  atest FrameworksCoreTests:TextViewActivityTest
Change-Id: I6e03a398ccb6fa5526d0a282fc114f4e80285099

1 files changed, 137 insertions, 0 deletions

diff --git a/core/java/android/widget/TextViewRichContentReceiver.java b/core/java/android/widget/TextViewRichContentReceiver.java
new file mode 100644
index 000000000000..125eaa7e6d9f
--- /dev/null
+++ b/core/java/android/widget/TextViewRichContentReceiver.java
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.widget;
+
+import android.annotation.NonNull;
+import android.content.ClipData;
+import android.content.Context;
+import android.text.Editable;
+import android.text.Selection;
+import android.text.SpannableStringBuilder;
+import android.text.Spanned;
+
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * Default implementation of {@link RichContentReceiver} for editable {@link TextView} components.
+ * This class handles insertion of text (plain text, styled text, HTML, etc) but not images or other
+ * rich content. Typically this class will be used as a delegate by custom implementations of
+ * {@link RichContentReceiver}, to provide consistent behavior for insertion of text while
+ * implementing custom behavior for insertion of other content (images, etc). See
+ * {@link TextView#DEFAULT_RICH_CONTENT_RECEIVER}.
+ *
+ * @hide
+ */
+final class TextViewRichContentReceiver implements RichContentReceiver<TextView> {
+    static final TextViewRichContentReceiver INSTANCE = new TextViewRichContentReceiver();
+
+    private static final Set<String> MIME_TYPES_ALL_TEXT = Collections.singleton("text/*");
+
+    @Override
+    public Set<String> getSupportedMimeTypes() {
+        return MIME_TYPES_ALL_TEXT;
+    }
+
+    @Override
+    public boolean onReceive(@NonNull TextView textView, @NonNull ClipData clip,
+            @Source int source, int flags) {
+        if (source == SOURCE_AUTOFILL) {
+            return onReceiveForAutofill(textView, clip, flags);
+        }
+        if (source == SOURCE_DRAG_AND_DROP) {
+            return onReceiveForDragAndDrop(textView, clip, flags);
+        }
+        if (source == SOURCE_INPUT_METHOD && !supports(clip.getDescription())) {
+            return false;
+        }
+
+        // The code here follows the original paste logic from TextView:
+        // https://cs.android.com/android/_/android/platform/frameworks/base/+/9fefb65aa9e7beae9ca8306b925b9fbfaeffecc9:core/java/android/widget/TextView.java;l=12644
+        // In particular, multiple items within the given ClipData will trigger separate calls to
+        // replace/insert. This is to preserve the original behavior with respect to TextWatcher
+        // notifications fired from SpannableStringBuilder when replace/insert is called.
+        final Editable editable = (Editable) textView.getText();
+        final Context context = textView.getContext();
+        boolean didFirst = false;
+        for (int i = 0; i < clip.getItemCount(); i++) {
+            CharSequence itemText;
+            if ((flags & FLAG_CONVERT_TO_PLAIN_TEXT) != 0) {
+                itemText = clip.getItemAt(i).coerceToText(context);
+                itemText = (itemText instanceof Spanned) ? itemText.toString() : itemText;
+            } else {
+                itemText = clip.getItemAt(i).coerceToStyledText(context);
+            }
+            if (itemText != null) {
+                if (!didFirst) {
+                    final int selStart = Selection.getSelectionStart(editable);
+                    final int selEnd = Selection.getSelectionEnd(editable);
+                    final int start = Math.max(0, Math.min(selStart, selEnd));
+                    final int end = Math.max(0, Math.max(selStart, selEnd));
+                    Selection.setSelection(editable, end);
+                    editable.replace(start, end, itemText);
+                    didFirst = true;
+                } else {
+                    editable.insert(Selection.getSelectionEnd(editable), "\n");
+                    editable.insert(Selection.getSelectionEnd(editable), itemText);
+                }
+            }
+        }
+        return didFirst;
+    }
+
+    private static boolean onReceiveForAutofill(@NonNull TextView textView, @NonNull ClipData clip,
+            int flags) {
+        final CharSequence text = coerceToText(clip, textView.getContext(), flags);
+        if (text.length() == 0) {
+            return false;
+        }
+        // First autofill it...
+        textView.setText(text);
+        // ...then move cursor to the end.
+        final Editable editable = (Editable) textView.getText();
+        Selection.setSelection(editable, editable.length());
+        return true;
+    }
+
+    private static boolean onReceiveForDragAndDrop(@NonNull TextView textView,
+            @NonNull ClipData clip, int flags) {
+        final CharSequence text = coerceToText(clip, textView.getContext(), flags);
+        if (text.length() == 0) {
+            return false;
+        }
+        textView.replaceSelectionWithText(text);
+        return true;
+    }
+
+    private static CharSequence coerceToText(ClipData clip, Context context, int flags) {
+        SpannableStringBuilder ssb = new SpannableStringBuilder();
+        for (int i = 0; i < clip.getItemCount(); i++) {
+            CharSequence itemText;
+            if ((flags & FLAG_CONVERT_TO_PLAIN_TEXT) != 0) {
+                itemText = clip.getItemAt(i).coerceToText(context);
+                itemText = (itemText instanceof Spanned) ? itemText.toString() : itemText;
+            } else {
+                itemText = clip.getItemAt(i).coerceToStyledText(context);
+            }
+            if (itemText != null) {
+                ssb.append(itemText);
+            }
+        }
+        return ssb;
+    }
+}