《HarmonyOS实战 — 事件》

【本文正在参与“有奖征文 | HarmonyOS征文大赛”活动】

一：事件的四种写法

<?xml version="1.0" encoding="utf-8"?><DirectionalLayout    xmlns:ohos="http://schemas.huawei.com/res/ohos"    ohos:height="match_parent"    ohos:width="match_parent"    ohos:alignment="center"    ohos:orientation="vertical">   <Text      ohos:id="$+id:text1"ohos:height="match_content"ohos:width="match_content"      ohos:text="text"      ohos:text_size="100"/>   <Buttonohos:id="$+id:but1"ohos:height="match_content"ohos:width="match_content"ohos:text="鐐规垜"ohos:text_size="50"ohos:background_element="red"/></DirectionalLayout>

package com.example.listenerapplication.slice;import com.example.listenerapplication.ResourceTable;import ohos.aafwk.ability.AbilitySlice;import ohos.aafwk.content.Intent;import ohos.agp.components.Button;import ohos.agp.components.Component;import ohos.agp.components.Text;public class MainAbilitySlice extends AbilitySlice  {    Text text1 = null;    @Override    public void onStart(Intent intent) { super.onStart(intent); super.setUIContent(ResourceTable.Layout_ability_main);  Button but1 = (Button) findComponentById(ResourceTable.Id_but1); text1 =  (Text) findComponentById(ResourceTable.Id_text1); //第一种 but1.setClickedListener(new MyListener()); //第二种 but1.setClickedListener(this);//第三种but1.setClickedListener(new Component.ClickedListener() {     @Override     public void onClick(Component component) {  Button btu = (Button) component;  btu.setText("被点了-单击事件的第三种写法");  text1.setText("被点击了");     } });//第四种 but1.setClickedListener(this::onClick);    }    @Override    public void onActive() { super.onActive();    }    @Override    public void onForeground(Intent intent) { super.onForeground(intent);    }    public void onClick(Component component) { Button btu = (Button) component; btu.setText("被点了-单击事件的第二种写法"); text1.setText("被点击了");    }}class MyListener implements Component.ClickedListener{    @Override    public void onClick(Component component) { //component：所有组件的父类 //参数：被点击的组件对象 //component.setText(); Button btu = (Button) component; btu.setText("被点了");    }}

二：其他事件

• 双击事件：DoubleClickedListener
• 长按事件：LongClickedListener
• 滑动事件：setTouchEventListener

//记录按下时手指的位置float startX = 0;float startY = 0;@Overridepublic boolean onTouchEvent(Component component, TouchEvent touchEvent) {count++;//参数一：component表示滑动的那个组件。（布局也是一种组件）//实际上此时代表的就是那个DirectionalLayout这个布局对象。//参数二：touchEvent 动作对象（按下，滑动，抬起）//获取当前手指对屏幕进行的操作（按下，滑动，抬起）int action = touchEvent.getAction();//1 表示按下操作//2 表示松开操作//3 表示滑动/移动操作if(action == TouchEvent.PRIMARY_POINT_DOWN){//只要写按下时需要运行的代码即可//text1.setText("按下" + count);//获取按下时手指的位置（坐标）/* MmiPoint point = touchEvent.getPointerPosition(0);startX = point.getX();startY = point.getY();*///text1.setText(x + "---" + y);text1.setText("按下");}else if(action == TouchEvent.POINT_MOVE){//移动/滑动//text1.setText("移动"+ count);/* MmiPoint point = touchEvent.getPointerPosition(0);float x = point.getX();float y = point.getY();text1.setText(x + "---" + y);*/text1.setText("移动");}else if(action == TouchEvent.PRIMARY_POINT_UP){text1.setText("松开");//松开手指//text1.setText("松开"+ count);/* MmiPoint point = touchEvent.getPointerPosition(0);float endX = point.getX();float endY = point.getY();//text1.setText(x + "---" + y);//拿着按下时手指的位置跟松开时手指的位置进行比较就可以if(endX > startX && Math.abs(endY - startY) < 100 ){text1.setText("右滑");}else if(endX < startX && Math.abs(endY - startY)  startY && Math.abs(endX - startX) < 100){text1.setText("下滑");}else if(endY < startY && Math.abs(endX - startX) < 100){text1.setText("上滑");}*/}//如果为true，表示所有的动作都会触发当前方法并执行对应代码。//如果为false，表示只有第一个动作会触发当前方法并执行对应代码。//后续的动作就不会触发当前方法了。//按下 --- 移动 --- 松开return true;}