1# Keyboard and Mouse Event 2 3 4Keyboard and mouse events refer to the input events of the peripheral keyboard and mouse. 5 6 7## Mouse Event 8 9The supported mouse events include the events triggered by the peripheral mouse and touchpad. 10 11Mouse events can trigger the following callbacks. 12 13| Name | Description | 14| ---------------------------------------- | ---------------------------------------- | 15| onHover(event: (isHover: boolean) => void) | Triggered when the mouse pointer enters or leaves the component.<br>**isHover**: whether the mouse pointer hovers over the component. The value **true** means that the mouse pointer enters the component, and the value **false** means that the mouse pointer leaves the component.| 16| onMouse(event: (event?: MouseEvent) => void) | Triggered when the component is clicked by a mouse button or the mouse pointer moves on the component. The **event** parameter indicates the timestamp, mouse button, action, coordinates of the clicked point on the entire screen, and coordinates of the clicked point relative to the component when the event is triggered.| 17 18When the component is bound to the **onHover** callback, you can use the [hoverEffect](../reference/apis-arkui/arkui-ts/ts-universal-attributes-hover-effect.md) attribute to set the hover effect of the component in hover state. 19 20 21 **Figure 1** Mouse event data flow 22 23 24 25 26 27When ArkUI receives the mouse event, it checks whether the mouse event concerns pressing, lifting, or moving of the left mouse button, and then responds accordingly. 28 29 30- Yes: The mouse event is first converted into a touch event in the same position, and a collision test, gesture judgment, and callback response of the touch event are performed. The collision test and callback response of the mouse event are then performed. 31 32- No: Only the collision test and callback response of the mouse event are performed. 33 34 35>**NOTE** 36> 37>All touch events and gesture events that can be responded to by a single finger may be triggered and responded to by using the left mouse button. For example, to implement page redirection invoked by clicking a button with support for finger touches and left-clicks, you just need to bind one click event (**onClick**). If you want to implement different effects for the finger touch and the left-click, you can use the **source** parameter in the **onClick** callback to determine whether the current event is triggered by a finger or a mouse. 38 39 40### onHover 41 42 43```ts 44onHover(event: (isHover?: boolean) => void) 45``` 46 47 48Triggered when the mouse pointer enters or leaves the component. The **isHover** parameter indicates whether the mouse pointer hovers over the component. This event does not support custom bubbling settings. By default, event bubbling occurs between parent and child components. 49 50 51If this API is bound to a component, it is triggered when the mouse pointer enters the component from outside and the value of **isHover** is **true**, or when the mouse pointer leaves the component and the value of **isHover** is **false**. 52 53 54>**NOTE** 55> 56>Event bubbling is an event propagation in the document object model (DOM) when an event is first handled by an element and then bubbles up to its parent element. 57 58 59 60 61```ts 62// xxx.ets 63@Entry 64@Component 65struct MouseExample { 66 @State hoverText: string = 'Not Hover'; 67 @State Color: Color = Color.Gray; 68 69 build() { 70 Column() { 71 Button(this.hoverText) 72 .width(200).height(100) 73 .backgroundColor(this.Color) 74 .onHover((isHover?: boolean) => { // Use the onHover API to listen for whether the mouse pointer is hovered over the button. 75 if (isHover) { 76 this.hoverText = 'Hovered!'; 77 this.Color = Color.Green; 78 } 79 else { 80 this.hoverText = 'Not Hover'; 81 this.Color = Color.Gray; 82 } 83 }) 84 }.width('100%').height('100%').justifyContent(FlexAlign.Center) 85 } 86} 87``` 88 89 90In this example, a **\<Button component>** is created, with the initial background color of gray and the content of **Not Hover**. The component is bound to the **onHover** callback. In the callback, **this.isHovered** is set to the callback parameter **isHover**. 91 92 93When the mouse pointer moves from outside the button to inside the button, the callback is invoked, the value of **isHover** changes to **true**, the value of **isHovered** changes to **true**, the background color of the component changes to **Color.Green**, and the content changes to **Hovered!**. 94 95 96When the mouse pointer moves from inside the button to outside the button, the callback is invoked, the value of **isHover** changes to **false**, and the component restores to its initial style. 97 98 99 100 101 102### onMouse 103 104 105```ts 106onMouse(event: (event?: MouseEvent) => void) 107``` 108 109 110Triggered when a mouse event occurs. It is triggered each time a mouse pointer action (**MouseAction**) is detected in the component. The parameter is a [MouseEvent](../reference/apis-arkui/arkui-ts/ts-universal-mouse-key.md#mouseevent) object, which indicates the mouse event that triggers the callback. This event supports custom bubbling settings. By default, event bubbling occurs between parent and child components. It is commonly used for customized mouse behavior logic processing. 111 112 113You can use the **MouseEvent** object in the callback to obtain information about the triggered event, including the coordinates (**displayX**, **displayY**, **windowX**, **windowY**, **x**, and **y**), button ([MouseButton](../reference/apis-arkui/arkui-ts/ts-appendix-enums.md#mousebutton)), action ([MouseAction](../reference/apis-arkui/arkui-ts/ts-appendix-enums.md#mouseaction)), timestamp (**timestamp**), display area of the object that triggers the event ([EventTarget](../reference/apis-arkui/arkui-ts/ts-universal-events-click.md#eventtarget8)), and event source ([SourceType](../reference/apis-arkui/arkui-ts/ts-gesture-settings.md#sourcetype)). The **stopPropagation** callback of **MouseEvent** is used to set whether the current event blocks bubbling. 114 115 116>**NOTE** 117> 118>**MouseButton** indicates the physical mouse button being pressed or released that triggers the mouse event. The values are **Left**, **Right**, **Middle**, **Back**, **Forward**, and **None**. **None** indicates that no button is pressed or released, which means that the event is triggered by the mouse pointer moving on the component. 119 120 121 122```ts 123// xxx.ets 124@Entry 125@Component 126struct MouseExample { 127 @State buttonText: string = ''; 128 @State columnText: string = ''; 129 @State hoverText: string = 'Not Hover'; 130 @State Color: Color = Color.Gray; 131 132 build() { 133 Column() { 134 Button(this.hoverText) 135 .width(200) 136 .height(100) 137 .backgroundColor(this.Color) 138 .onHover((isHover?: boolean) => { 139 if (isHover) { 140 this.hoverText = 'Hovered!'; 141 this.Color = Color.Green; 142 } 143 else { 144 this.hoverText = 'Not Hover'; 145 this.Color = Color.Gray; 146 } 147 }) 148 .onMouse((event?: MouseEvent) => { // Set the onMouse callback for the button. 149 if (event) { 150 this.buttonText = 'Button onMouse:\n' + '' + 151 'button = ' + event.button + '\n' + 152 'action = ' + event.action + '\n' + 153 'x,y = (' + event.x + ',' + event.y + ')' + '\n' + 154 'windowXY=(' + event.windowX + ',' + event.windowY + ')'; 155 } 156 }) 157 Divider() 158 Text(this.buttonText).fontColor(Color.Green) 159 Divider() 160 Text(this.columnText).fontColor(Color.Red) 161 } 162 .width('100%') 163 .height('100%') 164 .justifyContent(FlexAlign.Center) 165 .borderWidth(2) 166 .borderColor(Color.Red) 167 .onMouse((event?: MouseEvent) => { // Set the onMouse callback for the column. 168 if (event) { 169 this.columnText = 'Column onMouse:\n' + '' + 170 'button = ' + event.button + '\n' + 171 'action = ' + event.action + '\n' + 172 'x,y = (' + event.x + ',' + event.y + ')' + '\n' + 173 'windowXY=(' + event.windowX + ',' + event.windowY + ')'; 174 } 175 }) 176 } 177} 178``` 179 180 181Bind the **onMouse** API to the button based on the **onHover** example. In the callback, the values of the callback parameters, such as **button** and **action**, are displayed. The same settings are performed on the outer **\<Column>** container. The entire process can be divided into the following two actions: 182 183 1841. Moving the mouse pointer: When the mouse pointer is moved from outside the button to inside the button, only the **onMouse** callback of the **\<Column>** is triggered. When the mouse pointer is moved to the button, as the **onMouse** event bubbles up by default, both the **onMouse** callbacks of the **\<Column>** and **\<Button>** components are invoked. In this process, the mouse pointer moves, but no mouse button is clicked. Therefore, in the displayed information, the value of **button** is 0 (enumerated value of **MouseButton.None**) and the value of **action** is **3** (enumerated value of **MouseAction.Move**). 185 1862. Clicking the mouse button: After the mouse pointer enters the **\<Button>** component, the **\<Button>** component is clicked twice, namely, left-click and right-click. 187 Left-clicked: button = 1 (enumerated value of **MouseButton.Left**); action = 1 (enumerated value of **MouseAction.Press**); action = 2 (enumerated value of **MouseAction.Release**). 188 189 Right-click: button = 2 (enumerated value of **MouseButton.Right**); action = 1 (enumerated value of **MouseAction.Press**); action = 2 (enumerated value of **MouseAction.Release**) 190 191 192 193 194 195To prevent the mouse event from bubbling, call the **stopPropagation()** API. 196 197 198 199```ts 200class ish{ 201 isHovered:boolean = false 202 set(val:boolean){ 203 this.isHovered = val; 204 } 205} 206class butf{ 207 buttonText:string = '' 208 set(val:string){ 209 this.buttonText = val 210 } 211} 212@Entry 213@Component 214struct MouseExample { 215 @State isHovered:ish = new ish() 216 build(){ 217 Column(){ 218 Button(this.isHovered ? 'Hovered!' : 'Not Hover') 219 .width(200) 220 .height(100) 221 .backgroundColor(this.isHovered ? Color.Green : Color.Gray) 222 .onHover((isHover?: boolean) => { 223 if(isHover) { 224 let ishset = new ish() 225 ishset.set(isHover) 226 } 227 }) 228 .onMouse((event?: MouseEvent) => { 229 if (event) { 230 if (event.stopPropagation) { 231 event.stopPropagation(); // Prevent the onMouse event from bubbling. 232 } 233 let butset = new butf() 234 butset.set('Button onMouse:\n' + '' + 235 'button = ' + event.button + '\n' + 236 'action = ' + event.action + '\n' + 237 'x,y = (' + event.x + ',' + event.y + ')' + '\n' + 238 'windowXY=(' + event.windowX + ',' + event.windowY + ')'); 239 } 240 }) 241 } 242 } 243} 244``` 245 246 247To prevent the mouse event of the child component (**\<Button>**) from bubbling up to its parent component (**\<Column>**), use the **event** parameter in the **onMouse** callback of **\<Button>** to call the **stopPropagation** API. 248 249 250 251```ts 252event.stopPropagation() 253``` 254 255 256With bubbling prevented, the mouse event on the **\<Button>** component will trigger the **onMouse** callback of the **\<Button>** component, but not the **onMouse** callback of the **\<Column>** component. 257 258 259### hoverEffect 260 261 262```ts 263hoverEffect(value: HoverEffect) 264``` 265 266 267Sets the hover effect of the component in hover state. The parameter value type is **HoverEffect**. The **Auto**, **Scale**, and **Highlight** effects are preset and do not support customization. 268 269 270 **Table 1** HoverEffect 271 272| Enum| Description | 273| -------------- | ---------------------------------------- | 274| Auto | Default hover effect, which varies by component. | 275| Scale | Scale effect. When the mouse pointer is placed over the component, the component is scaled up from 100% to 105%. When the mouse pointer is moved away, the component is scaled down from 105% to 100%.| 276| Highlight | Background fade-in and fade-out effect. When the mouse pointer is placed over the component, a white layer with 5% opacity is applied to the background color of the component, resulting in a dimmed background. When the mouse pointer is moved away, the background color of the component is restored to the original style.| 277| None | No effect. | 278 279 280 281```ts 282// xxx.ets 283@Entry 284@Component 285struct HoverExample { 286 build() { 287 Column({ space: 10 }) { 288 Button('Auto') 289 .width(170).height(70) 290 Button('Scale') 291 .width(170).height(70) 292 .hoverEffect(HoverEffect.Scale) 293 Button('Highlight') 294 .width(170).height(70) 295 .hoverEffect(HoverEffect.Highlight) 296 Button('None') 297 .width(170).height(70) 298 .hoverEffect(HoverEffect.None) 299 }.width('100%').height('100%').justifyContent(FlexAlign.Center) 300 } 301} 302``` 303 304 305 306 307 308For the **\<Button>** component, **Auto** creates the same effect as **Scale**. 309 310 311## Key Event 312 313 **Figure 2** Key event data flow 314 315 316 317 318The key event is triggered by a device such as a peripheral keyboard, and is sent to the currently focused window after being converted by the driver and multi-mode processing. After obtaining the event, the window distributes the event to the input method (which consumes the key as the input). If the input method does not consume the key event, the window sends the event to the ArkUI framework. Therefore, when an input box component has focus and an input method is enabled, most key events are consumed by the input method. For example, a letter key is used by the input method to enter a letter in the input box, and an arrow key is used by the input method to switch to the desired candidate word. 319 320 321After the key event is sent to the ArkUI framework, it first identifies the complete focus chain, and then sends the key event one by one from the leaf node to the root node. 322 323 324### onKeyEvent 325 326 327```ts 328onKeyEvent(event: (event?: KeyEvent) => void) 329``` 330 331 332Triggered when the bound component has [focus](arkts-common-events-focus-event.md) and a key event occurs on the component. The callback parameter [KeyEvent](../reference/apis-arkui/arkui-ts/ts-universal-events-key.md#keyevent) can be used to obtain the information about the key event, including [KeyType](../reference/apis-arkui/arkui-ts/ts-appendix-enums.md#keytype), [keyCode](../reference/apis-input-kit/js-apis-keycode.md), **keyText**, [KeySource](../reference/apis-arkui/arkui-ts/ts-appendix-enums.md#keysource), **deviceId**, **metaKey**, **timestamp**, and **stopPropagation**. 333 334 335 336```ts 337// xxx.ets 338@Entry 339@Component 340struct KeyEventExample { 341 @State buttonText: string = ''; 342 @State buttonType: string = ''; 343 @State columnText: string = ''; 344 @State columnType: string = ''; 345 346 build() { 347 Column() { 348 Button('onKeyEvent') 349 .defaultFocus(true) 350 .width(140).height(70) 351 .onKeyEvent((event?: KeyEvent) => { // Set the onKeyEvent event for the button. 352 if(event){ 353 if (event.type === KeyType.Down) { 354 this.buttonType = 'Down'; 355 } 356 if (event.type === KeyType.Up) { 357 this.buttonType = 'Up'; 358 } 359 this.buttonText = 'Button: \n' + 360 'KeyType:' + this.buttonType + '\n' + 361 'KeyCode:' + event.keyCode + '\n' + 362 'KeyText:' + event.keyText; 363 } 364 }) 365 366 Divider() 367 Text(this.buttonText).fontColor(Color.Green) 368 369 Divider() 370 Text(this.columnText).fontColor(Color.Red) 371 }.width('100%').height('100%').justifyContent(FlexAlign.Center) 372 .onKeyEvent((event?: KeyEvent) => { // Set the onKeyEvent event for the parent container <Column>. 373 if(event){ 374 if (event.type === KeyType.Down) { 375 this.columnType = 'Down'; 376 } 377 if (event.type === KeyType.Up) { 378 this.columnType = 'Up'; 379 } 380 this.columnText = 'Column: \n' + 381 'KeyType:' + this.buttonType + '\n' + 382 'KeyCode:' + event.keyCode + '\n' + 383 'KeyText:' + event.keyText; 384 } 385 }) 386 } 387} 388``` 389 390 391In the preceding example, **onKeyEvent** is bound to the **\<Button>** component and its parent container **\<Column>**. After the application opens and loads a page, the first focusable non-container component in the component tree automatically obtains focus. Set the **\<Button>** component as the default focus of the current page. Because the **\<Button>** component is a child node of the **\<Column>** component, the **\<Column>** component also obtains focus. For details about the focus obtaining mechanism, see [Focus Event](arkts-common-events-focus-event.md). 392 393 394 395 396 397After the application is opened, press the following keys in sequence: Space, Enter, Left Ctrl, Left Shift, Letter A, and Letter Z. 398 399 4001. Because the **onKeyEvent** event bubbles by default, the **onKeyEvent** callbacks of both **\<Button>** and **\<Column>** are invoked. 401 4022. Each key has two callbacks, which correspond to **KeyType.Down** and **KeyType.Up** respectively, indicating that the key is pressed and then lifted. 403 404 405To prevent the key event of the **\<Button>** component from bubbling up to its parent container **\<Column>**, add the **event.stopPropagation()** API to the **onKeyEvent** callback of **\<Button>**. 406 407 408 409```ts 410// xxx.ets 411@Entry 412@Component 413struct KeyEventExample { 414 @State buttonText: string = ''; 415 @State buttonType: string = ''; 416 @State columnText: string = ''; 417 @State columnType: string = ''; 418 419 build() { 420 Column() { 421 Button('onKeyEvent') 422 .defaultFocus(true) 423 .width(140).height(70) 424 .onKeyEvent((event?: KeyEvent) => { 425 // Use stopPropagation to prevent the key event from bubbling up. 426 if(event){ 427 if(event.stopPropagation){ 428 event.stopPropagation(); 429 } 430 if (event.type === KeyType.Down) { 431 this.buttonType = 'Down'; 432 } 433 if (event.type === KeyType.Up) { 434 this.buttonType = 'Up'; 435 } 436 this.buttonText = 'Button: \n' + 437 'KeyType:' + this.buttonType + '\n' + 438 'KeyCode:' + event.keyCode + '\n' + 439 'KeyText:' + event.keyText; 440 } 441 }) 442 443 Divider() 444 Text(this.buttonText).fontColor(Color.Green) 445 446 Divider() 447 Text(this.columnText).fontColor(Color.Red) 448 }.width('100%').height('100%').justifyContent(FlexAlign.Center) 449 .onKeyEvent((event?: KeyEvent) => { // Set the onKeyEvent event for the parent container <Column>. 450 if(event){ 451 if (event.type === KeyType.Down) { 452 this.columnType = 'Down'; 453 } 454 if (event.type === KeyType.Up) { 455 this.columnType = 'Up'; 456 } 457 this.columnText = 'Column: \n' + 458 'KeyType:' + this.buttonType + '\n' + 459 'KeyCode:' + event.keyCode + '\n' + 460 'KeyText:' + event.keyText; 461 } 462 }) 463 } 464} 465``` 466 467 468 469