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鸿蒙跨设备协同绘画板开发指南 原创
进修的泡芙
发布于 2025-6-18 22:13
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鸿蒙跨设备协同绘画板开发指南
一、项目概述
本文将基于HarmonyOS开发一个多设备实时同步的协同绘画板应用，借鉴《鸿蒙跨端U同步》中游戏多设备同步的技术原理，实现多个设备间实时同步绘制内容的功能。该系统将包含画板绘制、颜色选择、笔触调整以及实时同步等核心功能。
二、技术架构
±--------------------+ ±--------------------+
绘画界面 <-----> 绘制同步服务
(DrawingSlice) (DrawingSyncService)
±---------±---------+ ±---------±---------+
±---------v----------+ ±---------v----------+
画布绘制引擎 分布式数据管理
(CanvasRenderer) (DistributedData)
±---------±---------+ ±---------±---------+
±---------v-----------------------------v----------+
HarmonyOS基础服务 |
±--------------------------------------------------+
三、核心代码实现
绘制数据模型
public class DrawingAction {
public enum ActionType { START, MOVE, END }
private ActionType type;
private float x;
private float y;
private int color;
private float strokeWidth;
private String deviceId;
// 构造方法
public DrawingAction(ActionType type, float x, float y, int color, float strokeWidth) {
this.type = type;
this.x = x;
this.y = y;
this.color = color;
this.strokeWidth = strokeWidth;
this.deviceId = DistributedDeviceInfo.getLocalDeviceId();
// JSON序列化
public JSONObject toJson() throws JSONException {
JSONObject json = new JSONObject();
json.put("type", type.name());
json.put("x", x);
json.put("y", y);
json.put("color", color);
json.put("strokeWidth", strokeWidth);
json.put("deviceId", deviceId);
json.put("timestamp", System.currentTimeMillis());
return json;
// JSON反序列化
public static DrawingAction fromJson(JSONObject json) throws JSONException {
DrawingAction action = new DrawingAction(
ActionType.valueOf(json.getString("type")),
(float) json.getDouble("x"),
(float) json.getDouble("y"),
json.getInt("color"),
(float) json.getDouble("strokeWidth")
);
action.deviceId = json.getString("deviceId");
return action;
// getter方法…
绘制同步服务
public class DrawingSyncService {
private static final String TAG = “DrawingSyncService”;
private static final String SYNC_CHANNEL = “drawing_sync”;
private static DrawingSyncService instance;
private DistributedDataManager dataManager;
private DrawingActionListener actionListener;
private DrawingSyncService(Context context) {
this.dataManager = DistributedDataManagerFactory.getInstance()
.createDistributedDataManager(context);
initDataListener();
public static synchronized DrawingSyncService getInstance(Context context) {
if (instance == null) {
instance = new DrawingSyncService(context);
return instance;
private void initDataListener() {
dataManager.registerDataChangeListener(SYNC_CHANNEL, new DataChangeListener() {
@Override
public void onDataChanged(String deviceId, String key, String value) {
try {
JSONObject json = new JSONObject(value);
DrawingAction action = DrawingAction.fromJson(json);
// 忽略本地设备发送的更新
if (!deviceId.equals(DistributedDeviceInfo.getLocalDeviceId())) {
if (actionListener != null) {
actionListener.onActionReceived(action);
}
catch (JSONException e) {
HiLog.error(TAG, "Failed to parse drawing action");
}
});
// 同步绘制动作
public void syncDrawingAction(DrawingAction action) {
try {
JSONObject json = action.toJson();
DistributedOptions options = new DistributedOptions();
options.setPriority(DistributedOptions.Priority.HIGH);
dataManager.putString(SYNC_CHANNEL,
json.toString(),
DistributedDataManager.PUT_MODE_RELIABLE,
options);
catch (JSONException e) {
HiLog.error(TAG, "Failed to serialize drawing action");
}
// 注册动作监听器
public void registerActionListener(DrawingActionListener listener) {
this.actionListener = listener;
// 取消注册监听器
public void unregisterActionListener() {
this.actionListener = null;
public interface DrawingActionListener {
void onActionReceived(DrawingAction action);
}
画布绘制组件
public class DrawingView extends Component implements Component.DrawTask, Component.TouchEventListener {
private static final String TAG = “DrawingView”;
private Paint paint;
private Path currentPath;
private List<DrawingPath> paths = new ArrayList<>();
private DrawingSyncService syncService;
// 当前绘制属性
private int currentColor = Color.BLACK;
private float currentStrokeWidth = 5f;
public DrawingView(Context context) {
super(context);
init();
public DrawingView(Context context, AttrSet attrSet) {
super(context, attrSet);
init();
private void init() {
addDrawTask(this);
setTouchEventListener(this);
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeCap(Paint.StrokeCap.ROUND);
paint.setStrokeJoin(Paint.StrokeJoin.ROUND);
syncService = DrawingSyncService.getInstance(getContext());
@Override
public void onDraw(Component component, Canvas canvas) {
// 绘制所有路径
for (DrawingPath path : paths) {
paint.setColor(path.getColor());
paint.setStrokeWidth(path.getStrokeWidth());
canvas.drawPath(path.getPath(), paint);
// 绘制当前路径
if (currentPath != null) {
paint.setColor(currentColor);
paint.setStrokeWidth(currentStrokeWidth);
canvas.drawPath(currentPath, paint);
}
@Override
public boolean onTouchEvent(Component component, TouchEvent touchEvent) {
float x = touchEvent.getPointerPosition(0).getX();
float y = touchEvent.getPointerPosition(0).getY();
switch (touchEvent.getAction()) {
case TouchEvent.PRIMARY_POINT_DOWN:
startNewPath(x, y);
syncService.syncDrawingAction(
new DrawingAction(DrawingAction.ActionType.START, x, y, currentColor, currentStrokeWidth));
break;
case TouchEvent.POINT_MOVE:
if (currentPath != null) {
currentPath.lineTo(x, y);
syncService.syncDrawingAction(
new DrawingAction(DrawingAction.ActionType.MOVE, x, y, currentColor, currentStrokeWidth));
invalidate();
break;
case TouchEvent.POINT_UP:
if (currentPath != null) {
paths.add(new DrawingPath(currentPath, currentColor, currentStrokeWidth));
currentPath = null;
syncService.syncDrawingAction(
new DrawingAction(DrawingAction.ActionType.END, x, y, currentColor, currentStrokeWidth));
invalidate();
break;
return true;
private void startNewPath(float x, float y) {
currentPath = new Path();
currentPath.moveTo(x, y);
// 设置画笔颜色
public void setColor(int color) {
this.currentColor = color;
// 设置画笔粗细
public void setStrokeWidth(float width) {
this.currentStrokeWidth = width;
// 清除画布
public void clear() {
paths.clear();
currentPath = null;
invalidate();
private static class DrawingPath {
private Path path;
private int color;
private float strokeWidth;
public DrawingPath(Path path, int color, float strokeWidth) {
this.path = path;
this.color = color;
this.strokeWidth = strokeWidth;
// getter方法…
}
绘画界面实现
public class DrawingSlice extends AbilitySlice {
private static final String TAG = “DrawingSlice”;
private DrawingView drawingView;
private DrawingSyncService syncService;
@Override
public void onStart(Intent intent) {
super.onStart(intent);
setUIContent(ResourceTable.Layout_drawing_layout);
// 初始化服务
syncService = DrawingSyncService.getInstance(this);
// 获取UI组件
drawingView = (DrawingView) findComponentById(ResourceTable.Id_drawing_view);
Button clearBtn = (Button) findComponentById(ResourceTable.Id_clear_btn);
Button colorRed = (Button) findComponentById(ResourceTable.Id_color_red);
Button colorGreen = (Button) findComponentById(ResourceTable.Id_color_green);
Button colorBlue = (Button) findComponentById(ResourceTable.Id_color_blue);
Slider strokeSlider = (Slider) findComponentById(ResourceTable.Id_stroke_slider);
// 设置按钮事件
clearBtn.setClickedListener(component -> drawingView.clear());
colorRed.setClickedListener(component -> drawingView.setColor(Color.RED));
colorGreen.setClickedListener(component -> drawingView.setColor(Color.GREEN));
colorBlue.setClickedListener(component -> drawingView.setColor(Color.BLUE));
strokeSlider.setValueChangedListener((slider, value, fromUser) -> {
if (fromUser) {
drawingView.setStrokeWidth(value);
});
// 注册同步监听器
syncService.registerActionListener(new DrawingSyncService.DrawingActionListener() {
@Override
public void onActionReceived(DrawingAction action) {
getUITaskDispatcher().asyncDispatch(() -> {
handleRemoteAction(action);
});
});
private void handleRemoteAction(DrawingAction action) {
float x = action.getX();
float y = action.getY();
switch (action.getType()) {
case START:
drawingView.startNewPath(x, y);
break;
case MOVE:
if (drawingView.getCurrentPath() != null) {
drawingView.getCurrentPath().lineTo(x, y);
break;
case END:
if (drawingView.getCurrentPath() != null) {
drawingView.getPaths().add(
new DrawingView.DrawingPath(drawingView.getCurrentPath(),
action.getColor(), action.getStrokeWidth()));
drawingView.setCurrentPath(null);
break;
drawingView.invalidate();
@Override
protected void onStop() {
super.onStop();
// 取消注册监听器
syncService.unregisterActionListener();
}
XML布局文件
<DirectionalLayout
xmlns:ohos=“http://schemas.huawei.com/res/ohos”
ohos:width=“match_parent”
ohos:height=“match_parent”
ohos:orientation=“vertical”>
<com.example.drawing.DrawingView
ohos:id="$+id:drawing_view"
ohos:width="match_parent"
ohos:height="0vp"
ohos:weight="1"
ohos:background_element="#FFFFFFFF"/>
<DirectionalLayout
ohos:width="match_parent"
ohos:height="wrap_content"
ohos:orientation="horizontal"
ohos:padding="8vp"
ohos:margin_top="8vp">
<Button
ohos:id="$+id:color_red"
ohos:width="40vp"
ohos:height="40vp"
ohos:background_element="#FFFF0000"
ohos:margin_right="8vp"/>
<Button
ohos:id="$+id:color_green"
ohos:width="40vp"
ohos:height="40vp"
ohos:background_element="#FF00FF00"
ohos:margin_right="8vp"/>
<Button
ohos:id="$+id:color_blue"
ohos:width="40vp"
ohos:height="40vp"
ohos:background_element="#FF0000FF"
ohos:margin_right="16vp"/>
<Slider
ohos:id="$+id:stroke_slider"
ohos:width="200vp"
ohos:height="wrap_content"
ohos:min_value="1"
ohos:max_value="20"
ohos:progress_value="5"/>
<Button
ohos:id="$+id:clear_btn"
ohos:width="80vp"
ohos:height="40vp"
ohos:text="清除"
ohos:margin_left="16vp"/>
</DirectionalLayout>
</DirectionalLayout>
四、与游戏同步技术的结合点
实时动作同步：类似游戏中玩家操作的实时同步，实现绘制动作的即时传输
数据压缩优化：借鉴游戏网络优化技术，减少绘制数据传输量
冲突解决机制：采用时间戳解决多设备同时绘制时的冲突
状态一致性：确保所有设备的画布状态最终一致
设备管理：利用HarmonyOS分布式能力实现设备自动发现和连接
五、项目扩展方向
更多绘制工具：添加矩形、圆形等形状绘制工具
图层管理：支持多层绘制和图层控制
历史记录：实现撤销/重做功能
图片导入：支持导入背景图片进行绘制
协作管理：创建和管理协作会话
六、总结
本协同绘画板应用实现了以下功能：
基于Canvas的流畅绘制体验
多设备间实时同步绘制内容
可自定义的画笔颜色和粗细
简洁直观的用户界面
高效的分布式数据传输
通过借鉴游戏中的同步技术，我们构建了一个高性能的跨设备协同绘画系统。该系统不仅适用于创意协作场景，也为开发者展示了如何利用HarmonyOS分布式能力构建复杂的实时协同应用。
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