# Window Title Bar Customization Development (ArkTS)
## Overview
### Introduction
As a crucial element of the GUI, the window title bar is located at the top of a window. It is intended to help users identify the purpose or content of the window, complete with some handy control options. OpenHarmony provides a default window title bar. You can customize it to match your needs. This topic provides guidance on customizing your title bar in ArkTS.
### Constraints
The .js files that contain the custom title bar code must be placed in **foundation/arkui/ace_engine/frameworks/core/components_ng/pattern/container_modal/interfaces**.
The JS files must be built into ABC files with the **foundation/arkui/ace_engine/frameworks/core/components_ng/pattern/container_modal/interfaces/BUILD.gn** file.
The build configuration must be specified in **foundation/arkui/ace_engine/frameworks/core/components_ng/pattern/BUILD.gn**.
## How to Develop
In this example, a custom system title bar is developed.
1. Write the following code in an .ets file.
```ts
import image from '@ohos.multimedia.image';
const TITLE_ICON_SIZE: string = '20vp'
const TITLE_PADDING_START: string = '20vp'
const TITLE_ELEMENT_MARGIN_HORIZONTAL: string = '12vp'
const TITLE_TEXT_FONT_SIZE: string = '16fp'
const TITLE_TEXT_FONT_WEIGHT: string = '500px'
const TITLE_ROW_HEIGHT: string = '37vp'
@Entry
@Component
struct Index {
@State appLabel: string = '';
@State appLabelColor: Color = 0xff000000;
@State appIcon: PixelMap | undefined = undefined;
// 1. Override the following methods to change the font color when the window obtains or loses focus.
onWindowFocused() {
this.appLabelColor = 0xff000000;
}
onWindowUnfocused() {
this.appLabelColor = 0x66000000;
}
// 2. Override the following methods for setting the application icon and name on the title bar.
setAppTitle(content: string ) {
this.appLabel = content;
}
setAppIcon(pixelMap: image.PixelMap) {
this.appIcon = pixelMap;
}
build() {
Row() {
// 3. Create an <Image> component for showing the application icon.
Image(this.appIcon)
.id("enhanceAppIcon")
.height(TITLE_ICON_SIZE)
.width(TITLE_ICON_SIZE)
.interpolation(ImageInterpolation.Medium)
.focusable(false)
.margin({ left: TITLE_PADDING_START, right: TITLE_ELEMENT_MARGIN_HORIZONTAL })
// 4. Create a <Text> component for showing the application name.
Text(this.appLabel)
.id("enhanceAppLabel")
.fontSize(TITLE_TEXT_FONT_SIZE)
.fontColor(this.appLabelColor)
.fontWeight(TITLE_TEXT_FONT_WEIGHT)
.maxLines(1)
.textOverflow({ overflow: TextOverflow.Ellipsis })
.textAlign(TextAlign.Start)
.layoutWeight(1.0)
}
.width('100%')
.height(TITLE_ROW_HEIGHT)
.justifyContent(FlexAlign.Start)
.alignItems(VerticalAlign.Center)
.padding({ top: 6, bottom: 6 })
}
}
```
2. Compile the .ets file into a .js file.
```js
const TITLE_ICON_SIZE = '20vp';
const TITLE_PADDING_START = '20vp';
const TITLE_ELEMENT_MARGIN_HORIZONTAL = '12vp';
const TITLE_TEXT_FONT_SIZE = '16fp';
const TITLE_TEXT_FONT_WEIGHT = '500px';
const TITLE_ROW_HEIGHT = '37vp'
export class Index extends ViewPU {
constructor(parent, params, __localStorage, elmtId = -1) {
super(parent, __localStorage, elmtId);
this.__appLabel = new ObservedPropertySimplePU('', this, "appLabel");
this.__textColor = new ObservedPropertySimplePU(0xff000000, this, "textColor");
this.__pixelMap = new ObservedPropertyObjectPU(undefined, this, "appIcon");
this.setInitiallyProvidedValue(params);
}
setInitiallyProvidedValue(params) {
if (params.textColor !== undefined) {
this.textColor = params.textColor;
}
if (params.appLabel !== undefined) {
this.appLabel = params.appLabel;
}
if (params.appIcon !== undefined) {
this.appIcon = params.appIcon;
}
}
updateStateVars(params) {
}
purgeVariableDependenciesOnElmtId(rmElmtId) {
this.__textColor.purgeDependencyOnElmtId(rmElmtId);
this.__appLabel.purgeDependencyOnElmtId(rmElmtId);
this.__appIcon.purgeDependencyOnElmtId(rmElmtId);
}
aboutToBeDeleted() {
this.__textColor.aboutToBeDeleted();
this.__appLabel.aboutToBeDeleted();
this.__appIcon.aboutToBeDeleted();
SubscriberManager.Get().delete(this.id__());
this.aboutToBeDeletedInternal();
}
get textColor() {
return this.__textColor.get();
}
set textColor(newValue) {
this.__textColor.set(newValue);
}
get appLabel() {
return this.__appLabel.get();
}
set appLabel(newValue) {
this.__appLabel.set(newValue);
}
get appIcon() {
return this.__appIcon.get();
}
set appIcon(newValue) {
this.__appIcon.set(newValue);
}
onWindowFocused() {
this.textColor = 0xff000000;
}
onWindowUnfocused() {
this.textColor = 0x66000000;
}
setAppTitle(content) {
this.appLabel = content;
}
setAppIcon(pixelMap) {
this.appIcon = pixelMap;
}
initialRender() {
this.observeComponentCreation((elmtId, isInitialRender) => {
ViewStackProcessor.StartGetAccessRecordingFor(elmtId);
Row.create();
Row.width('100%');
Row.height(TITLE_ROW_HEIGHT);
Row.justifyContent(FlexAlign.Start);
Row.alignItems(VerticalAlign.Center);
Row.padding({ top: 6, bottom: 6 });
if (!isInitialRender) {
Row.pop();
}
ViewStackProcessor.StopGetAccessRecording();
});
this.observeComponentCreation((elmtId, isInitialRender) => {
ViewStackProcessor.StartGetAccessRecordingFor(elmtId);
Image.create(this.appIcon);
Image.id("enhanceAppIcon");
Image.height(TITLE_ICON_SIZE);
Image.width(TITLE_ICON_SIZE);
Image.interpolation(ImageInterpolation.Medium);
Image.focusable(false);
Image.margin({ left: TITLE_PADDING_START, right: TITLE_ELEMENT_MARGIN_HORIZONTAL });
if (!isInitialRender) {
Image.pop();
}
ViewStackProcessor.StopGetAccessRecording();
});
this.observeComponentCreation((elmtId, isInitialRender) => {
ViewStackProcessor.StartGetAccessRecordingFor(elmtId);
Text.create(this.appLabel);
Image.id("enhanceAppLabel");
Text.maxLines(1);
Text.fontSize(TITLE_TEXT_FONT_SIZE);
Text.fontColor(this.textColor);
Text.fontWeight(TITLE_TEXT_FONT_WEIGHT);
Text.textOverflow({ overflow: TextOverflow.Ellipsis });
Text.textAlign(TextAlign.Start);
Text.layoutWeight(1.0);
if (!isInitialRender) {
Text.pop();
}
ViewStackProcessor.StopGetAccessRecording();
});
Text.pop();
Row.pop();
}
rerender() {
this.updateDirtyElements();
}
}
ViewStackProcessor.StartGetAccessRecordingFor(ViewStackProcessor.AllocateNewElmetIdForNextComponent());
// The loadDocument method needs to be changed to loadCustomTitleBar.
loadCustomTitleBar(new Index(undefined, {}));
ViewStackProcessor.StopGetAccessRecording();
```
- In general cases, the .js or .ts (.ets) files generated in DevEco Studio are stored in the **build/default/cache/default/default@CompileArkTS/esmodule/debug/entry/src/main/ets/pages/** directory of the project.
- Process the .ets file so that it complies with the JS syntax specifications.
- The **loadDocument** or **registerNameRouter** method in the .js file must be be changed to **loadCustomTitleBar**.
```js
loadCustomTitleBar(new Index(undefined, {}));
```
3. Use the **BUILD.gn** file to add the .js file as a system build dependency to generate an .abc file.
```
import("//arkcompiler/ets_frontend/es2panda/es2abc_config.gni")
es2abc_gen_abc("gen_customtitle_abc") {
src_js = rebase_path("customtitle.js")
dst_file = rebase_path(target_out_dir + "/customtitle.abc")
in_puts = [ "customtitle.js" ]
out_puts = [ target_out_dir + "/customtitle.abc" ]
extra_args = [ "--module" ]
}
```
Add **gen_customtitle_abc** to the build dependencies in the **foundation/arkui/ace_engine/frameworks/core/components_ng/pattern/BUILD.gn** file. The .abc file generated after compilation is stored in the **obj/foundation/arkui/ace_engine/frameworks/core/components_ng/pattern/container_modal/interfaces** directory.
For details, see the implementation in [foundation/arkui/ace_engine/frameworks/core/components_ng/pattern/container_modal/interfaces](https://gitee.com/openharmony/arkui_ace_engine/tree/master/frameworks/core/components_ng/pattern/container_modal/interfaces).
4. Add the .abc file to a specific directory in the system, for example, **/system/lib64/**, and run the following command to set **persist.sys.arkui.customtitle** to the path of the .abc file so that the custom title bar can be read and displayed properly.
```
hdc shell param set persist.sys.arkui.customtitle /system/lib64/customtitle.abc
```