Как сделать фото на методе DeviceAdminReceiver.onPasswordFailed?

Question

Я пытаюсь разработать приложение для Android, которое поможет определить, кто пытается получить доступ к моему мобильному телефону в случае неправильного шаблона / пин-кода. Я включил свое приложение в качестве администратора устройства и включил функцию электронной почты для запуска в случае неверного шаблона / пин-кода. Теперь я хочу сфотографироваться перед камерой и приложить к этому письму. Я попытался вызвать метод startActivity другого действия, которое поможет сделать снимок. но он не работает должным образом - он выдает следующее исключение:

Unable to start receiver com.example.lock.MyAdmin: 
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.intent.addCategory(java.lang.String)' on a null object reference

Я новичок в приложении для Android, поэтому, пожалуйста, помогите мне реализовать эту функцию.

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.lock">

    <uses-permission android:name="android.permission.INTERNET" />

    <uses-feature
        android:name="android.hardware.camera"
        android:required="true" />

    <uses-permission android:name="android.permission.CAMERA" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".CamActivity"
            android:label="@string/title_activity_cam"
            android:theme="@style/AppTheme.NoActionBar">

        </activity>
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver
            android:name=".MyAdmin"
            android:description="@string/sample_device_admin_description"
            android:label="@string/sample_device_admin"
            android:permission="android.permission.BIND_DEVICE_ADMIN">
            <meta-data
                android:name="android.app.device_admin"
                android:resource="@xml/policies" />

            <intent-filter>
                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
                <action android:name="android.app.action.ACTION_PASSWORD_FAILED" />
            </intent-filter>
        </receiver>
    </application>

</manifest>

MainActivity

public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
    private Button lock, disable, enable;
    public static final int RESULT_ENABLE = 11;
    private DevicePolicyManager devicePolicyManager;
    private ComponentName compName;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        devicePolicyManager = (DevicePolicyManager) getSystemService(DEVICE_POLICY_SERVICE);
        compName = new ComponentName(this, MyAdmin.class);

        lock = (Button) findViewById(R.id.Lock);
        enable = (Button) findViewById(R.id.enableBtn);
        disable = (Button) findViewById(R.id.disableBtn);
        lock.setOnClickListener(this);
        enable.setOnClickListener(this);
        disable.setOnClickListener(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        boolean isActive = devicePolicyManager.isAdminActive(compName);
        disable.setVisibility(isActive ? View.VISIBLE : View.GONE);
        enable.setVisibility(isActive ? View.GONE : View.VISIBLE);
    }

    @Override
    public void onClick(View view) {
        if (view == lock) {
            boolean active = devicePolicyManager.isAdminActive(compName);

            if (active) {
                devicePolicyManager.lockNow();
            } else {
                Toast.makeText(this, "You need to enable the Admin Device Features", Toast.LENGTH_SHORT).show();
            }

        } else if (view == enable) {
            Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
            intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, compName);
            intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "Additional text explaining why we need this permission");
            startActivityForResult(intent, RESULT_ENABLE);


        } else if (view == disable) {
            devicePolicyManager.removeActiveAdmin(compName);
            disable.setVisibility(View.GONE);
            enable.setVisibility(View.VISIBLE);
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch(requestCode) {
            case RESULT_ENABLE :
                if (resultCode == Activity.RESULT_OK) {
                    Toast.makeText(MainActivity.this, "You have enabled the Admin Device features", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(MainActivity.this, "Problem to enable the Admin Device features", Toast.LENGTH_SHORT).show();
                }
                break;
        }

        super.onActivityResult(requestCode, resultCode, data);
    }

}

MyAdmin

package com.example.lock;
import android.app.admin.DeviceAdminReceiver;
import android.app.admin.DevicePolicyManager;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;
import android.content.ComponentName;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import  android.provider.MediaStore;
import android.os.Environment;
import java.io.File;
import android.net.Uri;
import android.content.pm.PackageManager;

public class MyAdmin extends DeviceAdminReceiver {
    Context conn;
    public MyAdmin(Context con) {
        this.conn = con;
    }

    public MyAdmin() {
    }

    @Override
    public void onEnabled(Context context, Intent intent) {

        Toast.makeText(context, "Device Admin : enabled", Toast.LENGTH_SHORT).show();
        ComponentName cn =new ComponentName(context, MyAdmin.class);
        DevicePolicyManager mgr=
                (DevicePolicyManager)context.getSystemService(Context.DEVICE_POLICY_SERVICE);
        mgr.setPasswordQuality(cn,
                DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);
        onPasswordChanged(context, intent);

        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

        ComponentName receiver = new ComponentName(context, CamActivity.class);
        PackageManager pm = context.getPackageManager();
        Intent i = pm.getLaunchIntentForPackage("com.example.lock.CamActivity");
        i.addCategory(Intent.CATEGORY_LAUNCHER);
        context.startActivity(intent);

        //conn.startActivity(new Intent().setComponent(new ComponentName("com.example.lock", "com.example.lock.CamActivity")));
    }

    public void onPasswordChanged1(Context ctxt, Intent intent) {
        DevicePolicyManager mgr=
                (DevicePolicyManager)ctxt.getSystemService(Context.DEVICE_POLICY_SERVICE);
        int msgId;

        if (mgr.isActivePasswordSufficient()) {
            msgId=R.string.compliant;
        }
        else {
            msgId=R.string.not_compliant;
        }

        Toast.makeText(ctxt, msgId, Toast.LENGTH_LONG).show();
    }

    @Override
    public void onPasswordFailed(Context context, Intent intent) {
        int attempts =0;
        DevicePolicyManager DevicePolicyManager=
                (DevicePolicyManager)context.getSystemService(Context.DEVICE_POLICY_SERVICE);
        if(DevicePolicyManager != null)
            attempts = DevicePolicyManager.getCurrentFailedPasswordAttempts();

        AsyncCall EmailAsyncClient =new AsyncCall();
        EmailAsyncClient.execute("");

        Toast.makeText(context, R.string.password_failed, Toast.LENGTH_LONG)
                .show();
    }

    @Override
    public void onPasswordSucceeded(Context ctxt, Intent intent) {

        //MailService mailer = new MailService("From@gmail.com","To@gmail.com","Enable Attempt!","Please verify Your Phone!!!", "<b>HtmlBody</b>");
        Toast.makeText(ctxt, R.string.password_success, Toast.LENGTH_LONG)
                .show();
    }

    @Override
    public void onDisabled(Context context, Intent intent) {

        Toast.makeText(context, "Device Admin : disabled", Toast.LENGTH_SHORT).show();
    }

}

MailService

package com.example.lock;
import android.util.Log;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Properties;

import javax.activation.DataHandler;
import javax.mail.Authenticator;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMultipart;
import android.os.AsyncTask;

public class MailService {
    // public static final String MAIL_SERVER = "localhost";
    private String toList;
    private String ccList;
    private String bccList;
    private String subject;
    final private static String SMTP_SERVER = "smtp.gmail.com";
    private String from;
    private String txtBody;
    private String htmlBody;
    private String replyToList;
    //private ArrayList<Attachment> attachments;
    private boolean authenticationRequired = true;

    public MailService(String from, String toList, String subject, String txtBody, String htmlBody){
        //Attachment attachment) {
        this.txtBody = txtBody;
        this.htmlBody = htmlBody;
        this.subject = subject;
        this.from = from;
        this.toList = toList;
        this.ccList = null;
        this.bccList = null;
        this.replyToList = null;
        this.authenticationRequired = true;

        //this.attachments = new ArrayList<Attachment>();
        //if (attachment != null) {
        //    this.attachments.add(attachment);
        //}
    }


    public void sendAuthenticated() throws AddressException, MessagingException {
        authenticationRequired = true;
        send();
    }

    /**
     * Send an e-mail
     *
     * @throws MessagingException
     * @throws AddressException
     */
    public void send() throws AddressException, MessagingException {
        Properties props = new Properties();

        // set the host smtp address
        props.put("mail.smtp.host", SMTP_SERVER);
        props.put("mail.user", from);

        props.put("mail.smtp.starttls.enable", "true");  // needed for gmail
        props.put("mail.smtp.auth", "true"); // needed for gmail
        props.put("mail.smtp.port", "587");  // gmail smtp port

        Authenticator auth = new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("UserName", "Password");
            }
        };


        Session session;

        props.put("mail.smtp.auth", "true");
        session = Session.getDefaultInstance(props, auth);

        if (authenticationRequired) {
            //Authenticator auth = new SMTPAuthenticator();

        } else {
            session = Session.getDefaultInstance(props, null);
        }

        // get the default session
        //session.setDebug(true);

        // create message
        Message msg = new javax.mail.internet.MimeMessage(session);

        // set from and to address
        try {
            msg.setFrom(new InternetAddress(from, from));
            msg.setReplyTo(new InternetAddress[]{new InternetAddress(from,from)});
        } catch (Exception e) {
            new Throwable(e);
            msg.setFrom(new InternetAddress(from));
            msg.setReplyTo(new InternetAddress[]{new InternetAddress(from)});
        }

        // set send date
        msg.setSentDate(Calendar.getInstance().getTime());

        // parse the recipients TO address
        java.util.StringTokenizer st = new java.util.StringTokenizer(toList, ",");
        int numberOfRecipients = st.countTokens();

        javax.mail.internet.InternetAddress[] addressTo = new javax.mail.internet.InternetAddress[numberOfRecipients];

        int i = 0;
        while (st.hasMoreTokens()) {
            addressTo[i++] = new javax.mail.internet.InternetAddress(st
                    .nextToken());
        }
        msg.setRecipients(javax.mail.Message.RecipientType.TO, addressTo);

        // parse the replyTo addresses
        if (replyToList != null && !"".equals(replyToList)) {
            st = new java.util.StringTokenizer(replyToList, ",");
            int numberOfReplyTos = st.countTokens();
            javax.mail.internet.InternetAddress[] addressReplyTo = new javax.mail.internet.InternetAddress[numberOfReplyTos];
            i = 0;
            while (st.hasMoreTokens()) {
                addressReplyTo[i++] = new javax.mail.internet.InternetAddress(
                        st.nextToken());
            }
            msg.setReplyTo(addressReplyTo);
        }

        // parse the recipients CC address
        if (ccList != null && !"".equals(ccList)) {
            st = new java.util.StringTokenizer(ccList, ",");
            int numberOfCCRecipients = st.countTokens();

            javax.mail.internet.InternetAddress[] addressCC = new javax.mail.internet.InternetAddress[numberOfCCRecipients];

            i = 0;
            while (st.hasMoreTokens()) {
                addressCC[i++] = new javax.mail.internet.InternetAddress(st
                        .nextToken());
            }

            msg.setRecipients(javax.mail.Message.RecipientType.CC, addressCC);
        }

        // parse the recipients BCC address
        if (bccList != null && !"".equals(bccList)) {
            st = new java.util.StringTokenizer(bccList, ",");
            int numberOfBCCRecipients = st.countTokens();

            javax.mail.internet.InternetAddress[] addressBCC = new javax.mail.internet.InternetAddress[numberOfBCCRecipients];

            i = 0;
            while (st.hasMoreTokens()) {
                addressBCC[i++] = new javax.mail.internet.InternetAddress(st
                        .nextToken());
            }

            msg.setRecipients(javax.mail.Message.RecipientType.BCC, addressBCC);
        }

        // set header
        msg.addHeader("X-Mailer", "MyAppMailer");
        msg.addHeader("Precedence", "bulk");
        // setting the subject and content type
        msg.setSubject(subject);

        Multipart mp = new MimeMultipart("related");

        // set body message
        MimeBodyPart bodyMsg = new MimeBodyPart();
        bodyMsg.setText(txtBody, "iso-8859-1");
        //if (attachments.size()>0) htmlBody = htmlBody.replaceAll("#filename#",attachments.get(0).getFilename());
        //if (htmlBody.indexOf("#header#")>=0) htmlBody = htmlBody.replaceAll("#header#",attachments.get(1).getFilename());
        //if (htmlBody.indexOf("#footer#")>=0) htmlBody = htmlBody.replaceAll("#footer#",attachments.get(2).getFilename());

        bodyMsg.setContent(htmlBody, "text/html");
        mp.addBodyPart(bodyMsg);

        // set attachements if any
        //if (attachments != null && attachments.size() > 0) {
        //    for (i = 0; i < attachments.size(); i++) {
        //        Attachment a = attachments.get(i);
        //        BodyPart att = new MimeBodyPart();
        //        att.setDataHandler(new DataHandler(a.getDataSource()));
        //        att.setFileName( a.getFilename() );
        //        att.setHeader("Content-ID", "<" + a.getFilename() + ">");
        //        mp.addBodyPart(att);
        //    }
        // }
        msg.setContent(mp);

        // send it
        try {
            javax.mail.Transport.send(msg);
        } catch (Exception e) {
            new Throwable(e);
            e.printStackTrace();
        }

    }
    /**
     * SimpleAuthenticator is used to do simple authentication when the SMTP
     * server requires it.
     */
    private static class SMTPAuthenticator extends javax.mail.Authenticator {

        @Override
        protected PasswordAuthentication getPasswordAuthentication() {

            String username = "username";
            //DataService.getSetting(DataService.SETTING_SMTP_USER);
            String password = "password";
            //DataService.getSetting(DataService.SETTING_SMTP_PASSWORD);

            return new PasswordAuthentication(username, password);
        }
    }

    public String getToList() {
        return toList;
    }

    public void setToList(String toList) {
        this.toList = toList;
    }

    public String getCcList() {
        return ccList;
    }

    public void setCcList(String ccList) {
        this.ccList = ccList;
    }

    public String getBccList() {
        return bccList;
    }

    public void setBccList(String bccList) {
        this.bccList = bccList;
    }

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }

    public void setFrom(String from) {
        this.from = from;
    }

    public void setTxtBody(String body) {
        this.txtBody = body;
    }

    public void setHtmlBody(String body) {
        this.htmlBody = body;
    }

    public String getReplyToList() {
        return replyToList;
    }

    public void setReplyToList(String replyToList) {
        this.replyToList = replyToList;
    }

    public boolean isAuthenticationRequired() {
        return authenticationRequired;
    }

    public void setAuthenticationRequired(boolean authenticationRequired) {
        this.authenticationRequired = authenticationRequired;
    }

}