通过鸿蒙自定义属性，来创造一个可以为所欲为的自定义标题组件

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鸿蒙开发者社区官方账号 2021-03-04 18:24:54

文章标签 鸿蒙自定义控件自定义属性 文章分类 HarmonyOS 后端开发

之前已经写过一个在HarmonyOS中的自定义组件的案例，里面主要讲解了DrawTask这个接口的使用，从而让我们可以调用Canvas进行绘制。

在之前的案例帖子中，有人回复问我如何实现自定义属性，现在这篇专门针对自定义属性写一篇帖子，同时通过自定义属性自己封装了一个非常实用的标题栏TitleBar

不多说，首先上效果图

通过鸿蒙自定义属性，来创造一个可以为所欲为的自定义标题组件_自定义属性

这里主要真多标题栏的背景，标题文字、大小、颜色，左右两侧按钮是图标显示还是文字显示、是否显示分别进行了定制，后期用户使用只需要通过几个简单自定义属性的配置即可组合实现自己想要的效果。

具体实现思路如下，首先创建一个HarmonyOS Library模块mycustomtitlebar，在里面添加一个布局layout_titlebar.xml，代码如下

<?xml version="1.0" encoding="utf-8"?>
<DependentLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_content"
    ohos:width="match_parent">

    <Button
        ohos:id="$+id:title_bar_left"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:align_parent_start="true"
        ohos:left_padding="5vp"
        ohos:min_height="45vp"
        ohos:min_width="45vp"
        ohos:text_size="14fp"
        ohos:vertical_center="true"/>

    <Text
        ohos:id="$+id:titleText"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:center_in_parent="true"
        ohos:multiple_lines="false"
        ohos:text_size="17fp"/>

    <Button
        ohos:id="$+id:title_bar_right"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:align_parent_end="true"
        ohos:left_padding="5vp"
        ohos:min_height="45vp"
        ohos:min_width="45vp"
        ohos:right_margin="5vp"
        ohos:text_size="14fp"
        ohos:vertical_center="true"/>
</DependentLayout>

然后创建一个自定义组件对应的类CustomTitleBar，代码如下：

package com.xdw.mycustomtitlebar;

import ohos.agp.components.*;
import ohos.agp.utils.Color;
import ohos.app.Context;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;

/**
 * Created by 夏德旺 on 2021/3/4 10:01
 */
public class CustomTitleBar extends ComponentContainer {
    private static final String TAG = "CustomTitleBar";
    private static final HiLogLabel LABEL = new HiLogLabel(HiLog.DEBUG, 0, "TAG");
    public CustomTitleBar(Context context) {
        super(context);
    }

    public CustomTitleBar(Context context, AttrSet attrSet) {
        super(context, attrSet);
        //动态加载layout
        Component component = LayoutScatter.getInstance(context).parse(ResourceTable.Layout_layout_titlebar, null, false);
        Button leftBtn = (Button) component.findComponentById(ResourceTable.Id_title_bar_left);
        Text titleText = (Text) component.findComponentById(ResourceTable.Id_titleText);
        Button rightBtn = (Button) component.findComponentById(ResourceTable.Id_title_bar_right);
        //添加layout到父组件
        addComponent(component);
        //处理TitleBar背景色
        if(attrSet.getAttr("bg_color").isPresent()){
            component.setBackground(attrSet.getAttr("bg_color").get().getElement());
        }else{
            HiLog.error(LABEL,"attr bg_color is not present");
            component.setBackground(getBackgroundElement());
        }

        //处理标题文字
        if(attrSet.getAttr("title_text").isPresent()){
            titleText.setText(attrSet.getAttr("title_text").get().getStringValue());
        }else {
            HiLog.error(LABEL,"attr title_text is not present");
            titleText.setText("");
        }

        //处理标题大小
        if(attrSet.getAttr("title_size").isPresent()){
            titleText.setTextSize(attrSet.getAttr("title_size").get().getIntegerValue(), Text.TextSizeType.FP);
        }else {
            HiLog.error(LABEL,"attr title_size is not present");
        }
        //处理标题颜色
        if(attrSet.getAttr("title_color").isPresent()){
            titleText.setTextColor(attrSet.getAttr("title_color").get().getColorValue());
        }else{
            HiLog.error(LABEL,"attr title_color is not exist");
            titleText.setTextColor(Color.BLACK);
        }

        //处理左边按钮
        //获取是否要显示左边按钮
        if(attrSet.getAttr("left_button_visible").isPresent()){
            if(attrSet.getAttr("left_button_visible").get().getBoolValue()){
                leftBtn.setVisibility(VISIBLE);
            }else{
                leftBtn.setVisibility(INVISIBLE);
            }
        }else{
            //默认情况显示
            HiLog.error(LABEL,"attr right_button_visible is not exist");
            leftBtn.setVisibility(VISIBLE);
        }
        //处理左侧按钮的图标
        if(attrSet.getAttr("left_button_icon").isPresent()){
            leftBtn.setAroundElements(attrSet.getAttr("left_button_icon").get().getElement(),null,null,null);
        }else{
            HiLog.error(LABEL,"attr left_button_icon is not exist");
        }
        //处理左侧按钮的文本
        if(attrSet.getAttr("left_button_text").isPresent()){
            leftBtn.setText(attrSet.getAttr("left_button_text").get().getStringValue());
        }else{
            HiLog.error(LABEL,"attr left_button_text is not exist");
        }
        //处理左侧按钮的文本颜色
        if(attrSet.getAttr("left_button_text_color").isPresent()){
            leftBtn.setTextColor(attrSet.getAttr("left_button_text_color").get().getColorValue());
        }else{
            HiLog.error(LABEL,"attr left_button_text_color is not exist");
        }
        //处理左侧按钮的文本大小
        if(attrSet.getAttr("left_button_text_size").isPresent()){
            leftBtn.setTextSize(attrSet.getAttr("left_button_text_size").get().getIntegerValue(),Text.TextSizeType.FP);
        }else{
            HiLog.error(LABEL,"attr left_button_text_size is not exist");
        }

        //处理右边按钮
        //获取是否要显示右边按钮
        if(attrSet.getAttr("right_button_visible").isPresent()){
            if(attrSet.getAttr("right_button_visible").get().getBoolValue()){
                rightBtn.setVisibility(VISIBLE);
            }else{
                rightBtn.setVisibility(INVISIBLE);
            }
        }else{
            //默认情况显示
            HiLog.error(LABEL,"attr right_button_visible is not exist");
            rightBtn.setVisibility(VISIBLE);
        }

        //处理右侧按钮的图标
        if(attrSet.getAttr("right_button_icon").isPresent()){
            rightBtn.setAroundElements(attrSet.getAttr("right_button_icon").get().getElement(),null,null,null);
        }else{
            HiLog.error(LABEL,"attr right_button_icon is not exist");
        }
        //处理右侧按钮的文本
        if(attrSet.getAttr("right_button_text").isPresent()){
            rightBtn.setText(attrSet.getAttr("right_button_text").get().getStringValue());
        }else{
            HiLog.error(LABEL,"attr right_button_text is not exist");
        }
        //处理右侧按钮的文本颜色
        if(attrSet.getAttr("right_button_text_color").isPresent()){
            rightBtn.setTextColor(attrSet.getAttr("right_button_text_color").get().getColorValue());
        }else{
            HiLog.error(LABEL,"attr right_button_text_color is not exist");
        }
        //处理右侧按钮的文本大小
        if(attrSet.getAttr("right_button_text_size").isPresent()){
            rightBtn.setTextSize(attrSet.getAttr("right_button_text_size").get().getIntegerValue(),Text.TextSizeType.FP);
        }else{
            HiLog.error(LABEL,"attr right_button_text_size is not exist");
        }
    }

    public CustomTitleBar(Context context, AttrSet attrSet, String styleName) {
        super(context, attrSet, styleName);
    }
}