Update View translation APIs.

This change doesn't contain the virtual view part and the API
dispatchTranslationRequests, it will be done in another change.

Bug: 178046780
Test: manual
Test: atest CtsTranslationTestCases
CTS-Coverage-Bug: 177960696

Change-Id: I65fe1db19c9dff21c0caca425fbb7d08559e730b

1 files changed, 120 insertions, 0 deletions

diff --git a/core/java/android/widget/TextViewTranslationCallback.java b/core/java/android/widget/TextViewTranslationCallback.java
new file mode 100644
index 000000000000..296d93c88554
--- /dev/null
+++ b/core/java/android/widget/TextViewTranslationCallback.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2021 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.text.method.TranslationTransformationMethod;
+import android.util.Log;
+import android.view.View;
+import android.view.translation.UiTranslationManager;
+import android.view.translation.ViewTranslationCallback;
+import android.view.translation.ViewTranslationResponse;
+
+/**
+ * Default implementation for {@link ViewTranslationCallback} for {@link TextView} components.
+ * This class handles how to display the translated information for {@link TextView}.
+ *
+ * @hide
+ */
+public class TextViewTranslationCallback implements ViewTranslationCallback {
+
+    private static final String TAG = "TextViewTranslationCallback";
+
+    private static final boolean DEBUG = Log.isLoggable(UiTranslationManager.LOG_TAG, Log.DEBUG);
+
+    private TranslationTransformationMethod mTranslationTransformation;
+
+    /**
+     * Invoked by the platform when receiving the successful {@link ViewTranslationResponse} for the
+     * view that provides the translatable information by {@link View#createTranslationRequest} and
+     * sent by the platform.
+     */
+    void setTranslationTransformation(TranslationTransformationMethod method) {
+        if (method == null) {
+            if (DEBUG) {
+                Log.w(TAG, "setTranslationTransformation: should not set null "
+                        + "TranslationTransformationMethod");
+            }
+            return;
+        }
+        mTranslationTransformation = method;
+    }
+
+    TranslationTransformationMethod getTranslationTransformation() {
+        return mTranslationTransformation;
+    }
+
+    private void clearTranslationTransformation() {
+        if (DEBUG) {
+            Log.v(TAG, "clearTranslationTransformation: " + mTranslationTransformation);
+        }
+        mTranslationTransformation = null;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean onShowTranslation(@NonNull View view) {
+        if (mTranslationTransformation != null) {
+            ((TextView) view).setTransformationMethod(mTranslationTransformation);
+        } else {
+            if (DEBUG) {
+                // TODO(b/182433547): remove before S release
+                Log.w(TAG, "onShowTranslation(): no translated text.");
+            }
+        }
+        return true;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean onHideTranslation(@NonNull View view) {
+        // Restore to original text content.
+        if (mTranslationTransformation != null) {
+            ((TextView) view).setTransformationMethod(
+                    mTranslationTransformation.getOriginalTransformationMethod());
+        } else {
+            if (DEBUG) {
+                // TODO(b/182433547): remove before S release
+                Log.w(TAG, "onHideTranslation(): no translated text.");
+            }
+        }
+        return true;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean onClearTranslation(@NonNull View view) {
+        // Restore to original text content and clear TranslationTransformation
+        if (mTranslationTransformation != null) {
+            ((TextView) view).setTransformationMethod(
+                    mTranslationTransformation.getOriginalTransformationMethod());
+            clearTranslationTransformation();
+        } else {
+            if (DEBUG) {
+                // TODO(b/182433547): remove before S release
+                Log.w(TAG, "onClearTranslation(): no translated text.");
+            }
+        }
+        return true;
+    }
+}