• This is the fourth day of my participation in the August More Text Challenge.

1. Three actions for sliding events

• The interface name:TouchEventListener
• The sliding event is divided into three actions: hold down, move and lift.

PRIMARY_POINT_DOWN: Press not loose. POINT_MOVE: move. PRIMARY_POINT_UP: lift.Copy the code

• Method return value:

trueContinue to perform the following operations.falseIndicates that subsequent operations will not continue.Copy the code

• Involves the following three actions, according to the user press position and the panasonic position, you can identify the user is up, down, left, or right slide.

• For example, you can tell if the user is swiping right.

• For example, you can tell if the user is sliding down.

2. Implementation case: Press, move or release to modify the content of the text

• Because you have to slide across the screen, give the outermost layoutDirectionalLayoutSet the slide event, add aid
• Press, move, or lift to modify the content of the text
• New project: ListenerApplication4
• Code implementation

ability_main

• Take the default generated Text Text content, based on thisDirectionalLayoutThe layout andTextComponents separately addid

      
<DirectionalLayout
    ohos:id="$+id:dl"
    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="$+id:text1"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:background_element="$graphic:background_ability_main"
        ohos:layout_alignment="horizontal_center"
        ohos:text="$string:mainability_HelloWorld"
        ohos:text_size="40vp"
        />

</DirectionalLayout>
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MainAbilitySlice

• It is written using the current class as the implementation of the class interface

package com.xdr630.listenerapplication.slice;

import com.xdr630.listenerapplication.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Component;
import ohos.agp.components.DirectionalLayout;
import ohos.agp.components.Text;
import ohos.multimodalinput.event.TouchEvent;

public class MainAbilitySlice extends AbilitySlice implements Component.TouchEventListener {

    Text text1 = null;

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

        //1. Find the entire layout object first
        DirectionalLayout dl = (DirectionalLayout) findComponentById(ResourceTable.Id_dl);
        text1 = (Text) findComponentById(ResourceTable.Id_text1);

        //2. Add a sliding event to the layout
        // The onTouchEvent method of this class is called as we slide through the layout
        // The onTouchEvent method in this class is constantly called by the code during the move/release process
        dl.setTouchEventListener(this);
    }

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

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

    @Override
    public boolean onTouchEvent(Component component, TouchEvent touchEvent) {
        // Parameter 1: Component represents a sliding component (layout is also a component, so you can also use component to represent layout objects)
        // This represents the DirectionalLayout layout object, which covers the entire screen
        // Parameter 2: touchEvent represents the action object (press, slide, lift)

        // Get the current finger to operate the screen (press, slide, lift)
        int action = touchEvent.getAction();
        // 1: press down
        // 2: release operation
        // 3. Indicates a slide/move operation

        if (action == TouchEvent.PRIMARY_POINT_DOWN){
            // Just write the code that needs to run when pressed
            text1.setText("Press");
        }else if (action == TouchEvent.POINT_MOVE){
            // Move or slide
            text1.setText("Mobile");
        }else if (action == TouchEvent.PRIMARY_POINT_UP){
            // Release or lift
            text1.setText("Let go");
        }
        return true; }}Copy the code

• Run:

• Press:

• Mobile:

• Loosen the:

3. Press, slide, or release

• You can seeOne, two, threeThe numbers represent separatelyPRIMARY_POINT_DOWN (press), PRIMARY_POINT_UP (release), POINT_MOVE (move).Therefore, the parameters of the above code can also be directly replaced by numbers, but for more intuitive expression, it is recommended to use parameters, at a glance.
• For example, use numbers

	if (action == 1) {// Just write the code that needs to run when pressed
	    text1.setText("Press");
	}else if (action == 3) {// Move or slide
	    text1.setText("Mobile");
	}else if (action == 2) {// Release or lift
	    text1.setText("Let go");
	}
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4. Verify the press, move, release process, and the code will repeatedly call the onTouchEvent method in this class

• Based on the above code, define a member variable counterint count = 0

• The onTouchEvent method is called once, so it’s added once

• thecountAfter each operation

• When pressed, that’s the first call,countShould be1

• When moving with the mouse constantly moving, it will constantly callonTouchEventMethod,countWill be increasing

• It’s also called once when it’s released,countAdd to the previous values1

• Therefore, after verification:

The onTouchEvent method in this class is repeatedly called by the code as it presses, moves, and releases.