要在Android上使用ACRA发送邮件报告，您需要执行以下步骤：

1. 首先，确保您已经在项目的build.gradle文件中添加了ACRA依赖项。在dependencies部分添加以下代码：

implementation 'ch.acra:acra:5.7.0'
implementation 'ch.acra:acra-mail:5.7.0'

2. 在您的Application类中初始化ACRA。在onCreate方法中添加以下代码：

import org.acra.ACRA;
import org.acra.config.ACRAConfiguration;
import org.acra.config.ConfigurationBuilder;
import org.acra.sender.EmailIntentSender;
import org.acra.sender.ReportSender;
import org.acra.sender.ReportSenderFactory;

public class MyApplication extends Application {

    @Override
    public void onCreate() {
        super.onCreate();

        // 配置ACRA
        ACRAConfiguration config = new ConfigurationBuilder(this)
                .setBuildConfigClass(BuildConfig.class)
                .setReportSenderFactoryClasses(MailSenderFactory.class)
                .build();

        // 初始化ACRA
        ACRA.init(this, config);
    }

    public static class MailSenderFactory implements ReportSenderFactory {

        @Override
        public ReportSender create(Context context, ACRAConfiguration config) {
            // 设置邮件发送配置
            EmailIntentSender emailSender = new EmailIntentSender(context, config);
            return new EmailReportSender(emailSender);
        }

        @Override
        public boolean enabled(ACRAConfiguration config) {
            return true;
        }
    }

    public static class EmailReportSender implements ReportSender {

        private final EmailIntentSender emailSender;

        public EmailReportSender(EmailIntentSender emailSender) {
            this.emailSender = emailSender;
        }

        @Override
        public void send(CrashReportData reportData) throws ReportSenderException {
            // 发送邮件
            emailSender.send(reportData);
        }
    }
}

3. 创建一个新的Java类，用于配置邮件发送参数。在项目中创建一个名为"acra"的包，并在该包下创建一个名为"MailConfig"的Java类。添加以下代码：

package acra;

import org.acra.config.ConfigUtils;
import org.acra.config.ConfigurationBuilder;

public class MailConfig extends ConfigurationBuilder {

    public MailConfig() {
        // 设置邮件发送参数
        setMailTo("your-email@example.com");
        setSubject("ACRA Crash Report");
        setBody("Hi,\n\nThis is an automated crash report from ACRA.\n\nPlease find the crash report details below:\n\n");
        setResSubject(R.string.crash_report_subject);
        setReportFileName(R.string.crash_report_file_name);
        setReportAsFile(true);
    }
}

4. 在您的AndroidManifest.xml文件中，将Application类设置为MyApplication。在标签中添加以下属性：