Android / Java / Appium - Swipe (Scroll) Down does not work [Mobile App]

Question

Hi community: I'm fighting with a mobile application in Android.

I try to do a swipe (scroll) down to the final of the app, but it's impossible. I have red a lot about similar situations in the forum, but nothing could help me.

This is my tech stack below.

Appium version: 1.17.1
Java: 1.8

This is my POM file.

    <properties>
        <java.version>1.8</java.version>
        <junit.version>4.12</junit.version>
        <cucumber.version>1.2.4</cucumber.version>
        <maven.compiler.version>3.3</maven.compiler.version>
    </properties>
<dependencies>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-server</artifactId>
            <version>2.53.0</version>
        </dependency>
        <dependency>
            <groupId>io.appium</groupId>
            <artifactId>java-client</artifactId>
            <version>4.0.0</version>
        </dependency>
        <dependency>
            <groupId>commons-validator</groupId>
            <artifactId>commons-validator</artifactId>
            <version>1.5.1</version>
        </dependency>
        <dependency>
            <groupId>info.cukes</groupId>
            <artifactId>cucumber-java</artifactId>
            <version>${cucumber.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>info.cukes</groupId>
            <artifactId>cucumber-junit</artifactId>
            <version>${cucumber.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.testng</groupId>
            <artifactId>testng</artifactId>
            <version>6.10</version>
        </dependency>
        <dependency>
            <groupId>info.cukes</groupId>
            <artifactId>cucumber-testng</artifactId>
            <version>1.2.0</version>
        </dependency>
        <dependency>
        <groupId>org.aeonbits.owner</groupId>
        <artifactId>owner-java8</artifactId>
        <version>1.0.6</version>
    </dependency>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-java</artifactId>
            <version>2.51.0</version>
        </dependency>
        <dependency>
            <groupId>info.cukes</groupId>
            <artifactId>cucumber-java8</artifactId>
            <version>1.2.4</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>info.cukes</groupId>
            <artifactId>cucumber-picocontainer</artifactId>
            <version>1.2.4</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.8</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.8</version>
        </dependency>
        <dependency>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>2.19.1</version>
            <type>maven-plugin</type>
        </dependency>
        <dependency>
            <groupId>org.seleniumhq.selenium</groupId>
            <artifactId>selenium-firefox-driver</artifactId>
            <version>2.51.0</version>
        </dependency>
        <dependency>
            <groupId>net.masterthought</groupId>
            <artifactId>cucumber-reporting</artifactId>
            <version>3.4.0</version>
        </dependency>
    </dependencies>

The methods that I'm trying to use for this:

public void scrollToBottom(){

        JavascriptExecutor js = (JavascriptExecutor) driver;
        HashMap<String, String> scrollObject = new HashMap<>();
        scrollObject.put("direction", "down");
        js.executeScript("mobile: scroll", scrollObject);
    }

    public void swipeVertical(AppiumDriver driver, double startPercentage, double finalPercentage, double anchorPercentage, int duration) throws Exception {
        Dimension size = driver.manage().window().getSize();
        int anchor = (int) (size.width * anchorPercentage);
        int startPoint = (int) (size.height * startPercentage);
        int endPoint = (int) (size.height * finalPercentage);
        new TouchAction(driver).press(anchor, startPoint).waitAction((3000)).moveTo(anchor, endPoint).release().perform();
    }

Time after time I receive the next error:

java.lang.NullPointerException

Can anybody help me?

Answer 1

You need to add the element as well in the hashmap to swipe the page up or down. Appium will hold that element and swipe up/down.
You can do it like:

 JavascriptExecutor js = (JavascriptExecutor) driver;
 HashMap<String, String> scrollObject = new HashMap<>();
 scrollObject.put("direction", "up");
 scrollObject.put("element", ((RemoteWebElement) driver.findElementByAccessibilityId("id")).getId());
 js.executeScript("mobile: swipe", scrollObject);

Answer 2

The only useful method for the dependencies above is the next:

TouchAction action = new TouchAction(driver());
        AndroidDriver<WebElement> driver = (AndroidDriver<WebElement>) driver();
        int x = driver.manage().window().getSize().getWidth()/2;
        int y = driver.manage().window().getSize().getHeight()/2;
        action.longPress(x, y).moveTo(x, y-(y)).release().perform();

The bad thing is the swipe is slow.