鸿蒙组件使用教程,鸿蒙自定义组件之鸿蒙画板

初识鸿蒙OS 2.0

华为的鸿蒙OS 2.0是目前唯一个有希望和安卓、IOS对抗的全新生态系统。9月10日，在东莞正式发布。华为喊出了“HarmonyOS 2.0 连接无限可能”的口号，将是未来十年很有竞争力的优秀操作系统。

自定义Component

这里我编写一个简易的画板。

1.新建一个类DrawComponment 继承自Componment；

2.实现Component.TouchEventListener，用于对touch事件生成相应的path；

3.实现Component.DrawTask，用于把path画到屏幕上；

代码

DrawComponment

package com.quqx.draw;

import ohos.agp.components.Component;

import ohos.agp.render.Canvas;

import ohos.agp.render.Paint;

import ohos.agp.render.Path;

import ohos.agp.utils.Color;

import ohos.agp.utils.Point;

import ohos.app.Context;

import ohos.hiviewdfx.HiLog;

import ohos.hiviewdfx.HiLogLabel;

import ohos.media.image.PixelMap;

import ohos.multimodalinput.event.MmiPoint;

import ohos.multimodalinput.event.TouchEvent;

public class DrawComponment extends Component implements Component.DrawTask, Component.TouchEventListener {

private static final String TAG = "DrawComponment";

PixelMap mPixelMap;

Canvas mCanvas;

Path mPath = new Path();

Paint mPaint;

Point mPrePoint = new Point();

Point mPreCtrlPoint = new Point();

public DrawComponment(Context context) {

super(context);

//初始化paint

mPaint = new Paint();

mPaint.setColor(Color.WHITE);

mPaint.setStrokeWidth(5f);

mPaint.setStyle(Paint.Style.STROKE_STYLE);

//添加绘制任务

addDrawTask(this::onDraw);

//设置TouchEvent监听

setTouchEventListener(this::onTouchEvent);

}

@Override

public void onDraw(Component component, Canvas canvas) {

canvas.drawPath(mPath, mPaint);

}

@Override

public boolean onTouchEvent(Component component, TouchEvent touchEvent) {

switch (touchEvent.getAction()) {

case TouchEvent.PRIMARY_POINT_DOWN: {

//鸿蒙Log工具

HiLog.debug(new HiLogLabel(0, 0, TAG), "TouchEvent.PRIMARY_POINT_DOWN");

//获取点信息

MmiPoint point = touchEvent.getPointerPosition(touchEvent.getIndex());

mPath.reset();

mPath.moveTo(point.getX(), point.getY());

mPrePoint.position[0] = point.getX();

mPrePoint.position[1] = point.getY();

mPreCtrlPoint.position[0] = point.getX();

mPreCtrlPoint.position[1] = point.getY();

//PRIMARY_POINT_DOWN 一定要返回true

return true;

}

case TouchEvent.PRIMARY_POINT_UP:

break;

case TouchEvent.POINT_MOVE: {

HiLog.debug(new HiLogLabel(0, 0, TAG), "TouchEvent.POINT_MOVE");

MmiPoint point = touchEvent.getPointerPosition(touchEvent.getIndex());

Point currCtrlPoint = new Point((point.getX() + mPrePoint.position[0]) / 2,

(point.getY() + mPrePoint.position[1]) / 2);

//绘制三阶贝塞尔曲线

mPath.cubicTo(mPrePoint, mPreCtrlPoint, currCtrlPoint);

mPreCtrlPoint.position[0] = currCtrlPoint.position[0];

mPreCtrlPoint.position[1] = currCtrlPoint.position[1];

mPrePoint.position[0] = point.getX();

mPrePoint.position[1] = point.getY();

//更新显示

invalidate();

break;

}

}

return false;

}

}

MainAbilitySlice

package com.quqx.draw.slice;

import com.quqx.draw.DrawComponment;

import ohos.aafwk.ability.AbilitySlice;

import ohos.aafwk.content.Intent;

import ohos.agp.components.DirectionalLayout;

import ohos.agp.components.DirectionalLayout.LayoutConfig;

import ohos.agp.components.Text;

import ohos.agp.colors.RgbColor;

import ohos.agp.components.element.ShapeElement;

import ohos.agp.utils.Color;

import ohos.agp.utils.TextAlignment;

public class MainAbilitySlice extends AbilitySlice {

private DirectionalLayout myLayout = new DirectionalLayout(this);

@Override

public void onStart(Intent intent) {

super.onStart(intent);

LayoutConfig config = new LayoutConfig(LayoutConfig.MATCH_PARENT, LayoutConfig.MATCH_PARENT);

myLayout.setLayoutConfig(config);

DrawComponment drawComponment = new DrawComponment(this);

drawComponment.setLayoutConfig(config);

ShapeElement element = new ShapeElement();

element.setRgbColor(new RgbColor(0, 0, 0));

drawComponment.setBackground(element);

myLayout.addComponent(drawComponment);

super.setUIContent(myLayout);

}

@Override

public void onActive() {

super.onActive();

}

@Override

public void onForeground(Intent intent) {

super.onForeground(intent);

}

}

效果

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持云海天教程。

原文链接：https://blog.csdn.net/weixin_41820878/article/details/108691575