Implement TextInputPlugin on Android (#3144)

This plugin will eventually replace keyboard.mojom.

shell/platform/android/BUILD.gn

@@ -66,6 +66,8 @@ android_library("java") {
   java_files = [
     "io/flutter/plugin/common/ActivityLifecycleListener.java",
     "io/flutter/plugin/common/JSONMessageListener.java",
+    "io/flutter/plugin/editing/InputConnectionAdaptor.java",
+    "io/flutter/plugin/editing/TextInputPlugin.java",
     "io/flutter/plugin/platform/PlatformPlugin.java",
     "io/flutter/view/AccessibilityBridge.java",
     "io/flutter/view/FlutterMain.java",

shell/platform/android/io/flutter/plugin/editing/InputConnectionAdaptor.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugin.editing;
+
+import android.text.Editable;
+import android.text.Selection;
+import android.util.Log;
+import android.view.inputmethod.BaseInputConnection;
+import android.view.inputmethod.CompletionInfo;
+import android.view.inputmethod.CorrectionInfo;
+import android.view.inputmethod.EditorInfo;
+import android.view.KeyEvent;
+import android.view.View;
+import io.flutter.view.FlutterView;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+class InputConnectionAdaptor extends BaseInputConnection {
+    static final String TAG = "FlutterView";
+    static final String MESSAGE_NAME = "flutter/textinputclient";
+
+    private FlutterView mView;
+    private int mClient;
+    private JSONObject mOutgoingState;
+
+    public InputConnectionAdaptor(FlutterView view, int client) {
+        super(view, true);
+        mView = view;
+        mClient = client;
+        mOutgoingState = new JSONObject();
+    }
+
+    private void updateEditingState() {
+        try {
+            final Editable content = getEditable();
+            mOutgoingState.put("text", content.toString());
+            mOutgoingState.put("selectionBase", Selection.getSelectionStart(content));
+            mOutgoingState.put("selectionExtent", Selection.getSelectionEnd(content));
+            mOutgoingState.put("composingBase", BaseInputConnection.getComposingSpanStart(content));
+            mOutgoingState.put("composingExtent", BaseInputConnection.getComposingSpanEnd(content));
+
+            final JSONArray args = new JSONArray();
+            args.put(0, mClient);
+            args.put(1, mOutgoingState);
+            final JSONObject message = new JSONObject();
+            message.put("method", "TextInputClient.updateEditingState");
+            message.put("args", args);
+            mView.sendPlatformMessage(MESSAGE_NAME, message.toString(), null);
+        } catch (JSONException e) {
+            Log.e(TAG, "Unexpected error serializing editing state", e);
+        }
+    }
+
+    @Override
+    public boolean commitText(CharSequence text, int newCursorPosition) {
+        final boolean result = super.commitText(text, newCursorPosition);
+        updateEditingState();
+        return result;
+    }
+
+    @Override
+    public boolean deleteSurroundingText(int beforeLength, int afterLength) {
+        final boolean result = super.deleteSurroundingText(beforeLength, afterLength);
+        updateEditingState();
+        return result;
+    }
+
+    @Override
+    public boolean setComposingRegion(int start, int end) {
+        final boolean result = super.setComposingRegion(start, end);
+        updateEditingState();
+        return result;
+    }
+
+    @Override
+    public boolean setComposingText(CharSequence text, int newCursorPosition) {
+        final boolean result = super.setComposingText(text, newCursorPosition);
+        updateEditingState();
+        return result;
+    }
+
+    @Override
+    public boolean setSelection(int start, int end) {
+        final boolean result = super.setSelection(start, end);
+        updateEditingState();
+        return result;
+    }
+
+    @Override
+    public boolean sendKeyEvent(KeyEvent event) {
+        final boolean result = super.sendKeyEvent(event);
+        if (event.getAction() == KeyEvent.ACTION_UP) {
+            // Weird special case. This method is (sometimes) called for the backspace key in 2
+            // situations:
+            // 1. There is no selection. In that case, we want to delete the previous character.
+            // 2. There is a selection. In that case, we want to delete the selection.
+            //    event.getNumber() is 0, and commitText("", 1) will do what we want.
+            if (event.getKeyCode() == KeyEvent.KEYCODE_DEL &&
+                mOutgoingState.optInt("selectionBase", -1) == mOutgoingState.optInt("selectionExtent", -1)) {
+                deleteSurroundingText(1, 0);
+            } else {
+                String text = event.getNumber() == 0 ? "" : String.valueOf(event.getNumber());
+                commitText(text, 1);
+            }
+        }
+        return result;
+    }
+
+    @Override
+    public boolean performEditorAction(int actionCode) {
+        try {
+            // TODO(abarth): Support more actions.
+            final JSONArray args = new JSONArray();
+            args.put(0, mClient);
+            args.put(1, "TextInputAction.done");
+            final JSONObject message = new JSONObject();
+            message.put("method", "TextInputClient.performAction");
+            message.put("args", args);
+            mView.sendPlatformMessage(MESSAGE_NAME, message.toString(), null);
+            return true;
+        } catch (JSONException e) {
+            Log.e(TAG, "Unexpected error serializing editor action", e);
+            return false;
+        }
+    }
+}

shell/platform/android/io/flutter/plugin/editing/TextInputPlugin.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugin.editing;
+
+import android.app.Activity;
+import android.content.Context;
+import android.text.Editable;
+import android.text.InputType;
+import android.text.Selection;
+import android.text.SpannableStringBuilder;
+import android.util.Log;
+import android.view.inputmethod.EditorInfo;
+import android.view.inputmethod.InputConnection;
+import android.view.inputmethod.InputMethodManager;
+import android.view.View;
+import io.flutter.plugin.common.JSONMessageListener;
+import io.flutter.view.FlutterView;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/**
+ * Android implementation of the text input plugin.
+ */
+public class TextInputPlugin extends JSONMessageListener {
+    private static final String TAG = "FlutterView";
+
+    private final Activity mActivity;
+    private int mClient = 0;
+    private JSONObject mConfiguration;
+    private JSONObject mIncomingState;
+
+    public TextInputPlugin(Activity activity) {
+        mActivity = activity;
+    }
+
+    @Override
+    public JSONObject onJSONMessage(FlutterView view, JSONObject message) throws JSONException {
+        String method = message.getString("method");
+        JSONArray args = message.getJSONArray("args");
+        if (method.equals("TextInput.show")) {
+            showTextInput(view);
+        } else if (method.equals("TextInput.hide")) {
+            hideTextInput(view);
+        } else if (method.equals("TextInput.setClient")) {
+            setTextInputClient(view, args.getInt(0), args.getJSONObject(0));
+        } else if (method.equals("TextInput.setEditingState")) {
+            setTextInputEditingState(view, args.getJSONObject(0));
+        } else if (method.equals("TextInput.clearClient")) {
+            clearTextInputClient();
+        } else {
+            // TODO(abarth): We should throw an exception here that gets
+            // transmitted back to Dart.
+        }
+        return null;
+    }
+
+    private static int inputTypeFromTextInputType(String inputType) {
+        if (inputType.equals("TextInputType.datetime"))
+            return InputType.TYPE_CLASS_DATETIME;
+        if (inputType.equals("TextInputType.datetime"))
+            return InputType.TYPE_CLASS_NUMBER;
+        if (inputType.equals("TextInputType.datetime"))
+            return InputType.TYPE_CLASS_PHONE;
+        return InputType.TYPE_CLASS_TEXT;
+    }
+
+    public InputConnection createInputConnection(FlutterView view, EditorInfo outAttrs) {
+        if (mClient == 0)
+            return null;
+        try {
+            outAttrs.inputType = inputTypeFromTextInputType(mConfiguration.getString("inputType"));
+            outAttrs.actionLabel = mConfiguration.getString("actionLabel");
+            outAttrs.imeOptions = EditorInfo.IME_ACTION_DONE | EditorInfo.IME_FLAG_NO_FULLSCREEN;
+            InputConnectionAdaptor connection = new InputConnectionAdaptor(view, mClient);
+            if (mIncomingState != null) {
+                outAttrs.initialSelStart = mIncomingState.getInt("selectionBase");
+                outAttrs.initialSelEnd = mIncomingState.getInt("selectionExtent");
+                connection.getEditable().append(mIncomingState.getString("text"));
+                connection.setSelection(mIncomingState.getInt("selectionBase"),
+                                        mIncomingState.getInt("selectionExtent"));
+                connection.setComposingRegion(mIncomingState.getInt("composingBase"),
+                                              mIncomingState.getInt("composingExtent"));
+            } else {
+                outAttrs.initialSelStart = 0;
+                outAttrs.initialSelEnd = 0;
+            }
+            return connection;
+        } catch (JSONException e) {
+            Log.e(TAG, "Failed to create input connection", e);
+        }
+        return null;
+    }
+
+    private void showTextInput(FlutterView view) {
+        InputMethodManager imm =
+                (InputMethodManager) mActivity.getSystemService(Context.INPUT_METHOD_SERVICE);
+        imm.showSoftInput(view, 0);
+    }
+
+    private void hideTextInput(FlutterView view) {
+        InputMethodManager imm =
+                (InputMethodManager) mActivity.getSystemService(Context.INPUT_METHOD_SERVICE);
+        imm.hideSoftInputFromWindow(view.getApplicationWindowToken(), 0);
+    }
+
+    private void setTextInputClient(FlutterView view, int client, JSONObject configuration) throws JSONException {
+        mIncomingState = null;
+        mClient = client;
+        mConfiguration = configuration;
+        InputMethodManager imm =
+                (InputMethodManager) mActivity.getSystemService(Context.INPUT_METHOD_SERVICE);
+        imm.restartInput(view);
+    }
+
+    private void setTextInputEditingState(FlutterView view, JSONObject state) throws JSONException {
+        mIncomingState = state;
+        InputMethodManager imm =
+                (InputMethodManager) mActivity.getSystemService(Context.INPUT_METHOD_SERVICE);
+        imm.restartInput(view);
+    }
+
+    private void clearTextInputClient() {
+        mClient = 0;
+    }
+}

shell/platform/android/io/flutter/view/FlutterView.java

@@ -60,6 +60,7 @@ import java.util.Locale;
 import java.util.Map;
 
 import io.flutter.plugin.common.ActivityLifecycleListener;
+import io.flutter.plugin.editing.TextInputPlugin;
 import io.flutter.plugin.platform.PlatformPlugin;
 
 import org.domokit.editing.KeyboardImpl;
@@ -77,6 +78,8 @@ public class FlutterView extends SurfaceView
     private static final String ACTION_DISCOVER = "io.flutter.view.DISCOVER";
 
     private long mNativePlatformView;
+    private TextInputPlugin mTextInputPlugin;
+
     private SkyEngine.Proxy mSkyEngine;
     private ServiceProviderImpl mPlatformServiceProvider;
     private Binding mPlatformServiceProviderBinding;
@@ -159,6 +162,8 @@ public class FlutterView extends SurfaceView
         PlatformPlugin platformPlugin = new PlatformPlugin((Activity)getContext());
         addOnMessageListener("flutter/platform", platformPlugin);
         addActivityLifecycleListener(platformPlugin);
+        mTextInputPlugin = new TextInputPlugin((Activity)getContext());
+        addOnMessageListener("flutter/textinput", mTextInputPlugin);
 
         if ((context.getApplicationInfo().flags & ApplicationInfo.FLAG_DEBUGGABLE) != 0) {
             discoveryReceiver = new DiscoveryReceiver();
@@ -181,7 +186,7 @@ public class FlutterView extends SurfaceView
             message.put("type", "keyup");
             message.put("keymap", "android");
             encodeKeyEvent(event, message);
-            dispatchPlatformMessage("flutter/keyevent", message.toString(), null);
+            sendPlatformMessage("flutter/keyevent", message.toString(), null);
         } catch (JSONException e) {
             Log.e(TAG, "Failed to serialize key event", e);
         }
@@ -195,7 +200,7 @@ public class FlutterView extends SurfaceView
             message.put("type", "keydown");
             message.put("keymap", "android");
             encodeKeyEvent(event, message);
-            dispatchPlatformMessage("flutter/keyevent", message.toString(), null);
+            sendPlatformMessage("flutter/keyevent", message.toString(), null);
         } catch (JSONException e) {
             Log.e(TAG, "Failed to serialize key event", e);
         }
@@ -269,7 +274,10 @@ public class FlutterView extends SurfaceView
 
     @Override
     public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
-        return mKeyboardState.createInputConnection(outAttrs);
+        InputConnection connection = mKeyboardState.createInputConnection(outAttrs);
+        if (connection == null)
+          connection = mTextInputPlugin.createInputConnection(this, outAttrs);
+        return connection;
     }
 
     // Must match the PointerChange enum in pointer.dart.
@@ -738,7 +746,12 @@ public class FlutterView extends SurfaceView
         return true;
     }
 
-    private void dispatchPlatformMessage(String name, String message, MessageReplyCallback callback) {
+    /**
+     * Send a message to the Flutter application. The Flutter application can
+     * register a platform message handler that will receive these messages with
+     * the PlatformMessages object.
+     */
+    public void sendPlatformMessage(String name, String message, MessageReplyCallback callback) {
         int responseId = 0;
         if (callback != null) {
             responseId = mNextResponseId++;