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這篇文章運用簡單易懂的例子給大家介紹鴻蒙自定義組件之鴻蒙畫板的概述,內容非常詳細,感興趣的小伙伴們可以參考借鑒,希望對大家能有所幫助。
初識鴻蒙OS 2.0
華為的鴻蒙OS 2.0是目前唯一個有希望和安卓、IOS對抗的全新生態系統。9月10日,在東莞正式發布。華為喊出了“HarmonyOS 2.0 連接無限可能”的口號,將是未來十年很有競爭力的優秀操作系統。
自定義Component
這里我編寫一個簡易的畫板。
1.新建一個類DrawComponment 繼承自Componment;
2.實現Component.TouchEventListener,用于對touch事件生成相應的path;
3.實現Component.DrawTask,用于把path畫到屏幕上;
代碼
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); //添加繪制任務 addDrawTask(this::onDraw); //設置TouchEvent監聽 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: { //鴻蒙Log工具 HiLog.debug(new HiLogLabel(0, 0, TAG), "TouchEvent.PRIMARY_POINT_DOWN"); //獲取點信息 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); //繪制三階貝塞爾曲線 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(); //更新顯示 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); } }
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