鸿蒙应用开发学习2——事件学习

MainAbilitySlice 继承了父类AbilitySlice ，该类是一个界面的类，
findComponentById是找到按钮的对象并返回。通过ID进行查找。其中Id_but1的类型是Id,名字是but1。findComponentById返回的是一个父类对象，需要向下转型。
ResourceTable是一个鸿蒙中界面的资源列表。如下图所示，每一个资源都有一个固定的ID。
后面的值是在内存中的地址值。通过ID可以找到按钮。

给按钮设置单击事件：setClickedListener。参数是单击按钮后要执行的操作。具体操作需要继承一个父类，重写onClick方法。

public class MainAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        // 1.找到按钮
        Button but1 = (Button) findComponentById(ResourceTable.Id_but1);

        // 2.给按钮绑定一个单击事件   setClickedListener需要传入一个接口实现类作为参数
        but1.setClickedListener(new MyListener());
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}

class MyListener implements ClickedListener{
    boolean flag = false;
    @Override
    public void onClick(ohos.agp.components.Component component) {
        if (!flag) {
            Button btu = (Button) component;
            btu.setText("被点击");
            flag = true;
        }
        else {
            Button btu = (Button) component;
            btu.setText("点我");
            flag = false;
        }

    }
}

public class MainAbilitySlice extends AbilitySlice implements ClickedListener {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        // 1.找到按钮
        Button but1 = (Button) findComponentById(ResourceTable.Id_but1);

        // 2.给按钮绑定一个单击事件   setClickedListener需要传入一个接口实现类作为参数
        but1.setClickedListener(this);
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
    boolean flag = false;
    @Override
    public void onClick(Component component) {
        if (!flag) {
            Button btu = (Button) component;
            btu.setText("被点击");
            flag = true;
        }
        else {
            Button btu = (Button) component;
            btu.setText("点我");
            flag = false;
        }
    }
}

public class MainAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        // 1.找到按钮
        Button but1 = (Button) findComponentById(ResourceTable.Id_but1);

        // 2.给but1绑定的单击事件
        but1.setClickedListener(new ClickedListener() {
            @Override
            public void onClick(Component component) {
                if (!flag) {
                    Button btu = (Button) component;
                    btu.setText("被点击");
                    flag = true;
                }
                else {
                    Button btu = (Button) component;
                    btu.setText("点我");
                    flag = false;
                }
            }
        });
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
    boolean flag = false;
}

public class MainAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        // 1.找到按钮
        Button but1 = (Button) findComponentById(ResourceTable.Id_but1);

        // 2.给but1绑定的单击事件
        but1.setClickedListener(this::onClick);
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
    boolean flag = false;
    public void onClick(Component component) {
        if (!flag) {
            Button btu = (Button) component;
            btu.setText("被点击");
            flag = true;
        }
        else {
            Button btu = (Button) component;
            btu.setText("点我");
            flag = false;
        }
    }
}

import ohos.agp.components.Component.ClickedListener;
import ohos.agp.components.Component.DoubleClickedListener;
import ohos.agp.components.Component.LongClickedListener;

public class MainAbilitySlice extends AbilitySlice implements DoubleClickedListener, LongClickedListener{
    boolean flag = false;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        // 1.找到按钮
        Button but1 = (Button) findComponentById(ResourceTable.Id_but1);
        Button but2 = (Button) findComponentById(ResourceTable.Id_but2);
        Button but3 = (Button) findComponentById(ResourceTable.Id_but3);

        // 2.给but1绑定的单击事件
        but1.setClickedListener(this::onClick);
        but2.setDoubleClickedListener(this);
        but3.setLongClickedListener(this);
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }

    public void onClick(Component component) {
        if (!flag) {
            Button btu = (Button) component;
            btu.setText("被点击");
            flag = true;
        }
        else {
            Button btu = (Button) component;
            btu.setText("点我");
            flag = false;
        }
    }

    @Override
    public void onDoubleClick(Component component) {
        if (!flag) {
            Button btu = (Button) component;
            btu.setText("被点击");
            flag = true;
        }
        else {
            Button btu = (Button) component;
            btu.setText("点我");
            flag = false;
        }
    }

    @Override
    public void onLongClicked(Component component) {
        if (!flag) {
            Button btu = (Button) component;
            btu.setText("被长按");
            flag = true;
        }
        else {
            Button btu = (Button) component;
            btu.setText("长按我");
            flag = false;
        }
    }

主要有2点：判断按下的起点和终点位置，检测按键按下滑动松开动作

    // 参数1：component表示滑动的那个组件（布局也是一种组件）
    // 参数2：touchEvent动作对象（按下，滑动，抬起）
    @Override
    public boolean onTouchEvent(Component component, TouchEvent touchEvent) {
        int action = touchEvent.getAction(); // 获取当前手指对屏幕进行的操作（按下，滑动，抬起）
        // 1 表示按下
        // 2 表示松开
        // 3 表示滑动/移动操作
        if (action == TouchEvent.PRIMARY_POINT_DOWN) {
            text1.setText("按下");
        } else if (action == TouchEvent.POINT_MOVE) {
            text1.setText("移动");
        } else if (action == TouchEvent.PRIMARY_POINT_UP) {
            text1.setText("松开");
        }

        return true;
    }