想让一个apk开启自动运行，可以通过Android系统中的广播机制实现开机自启动。
广播（Broadcast）是Android系统的四大组件之一，通过该机制可以实现不同应用程序之间的通信。
实现Apk开启自启动，进行如下两步操作即可：

1、添加广播接收器文件： 

BroadcastReceiver.java

package com.face.detail;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;


public class BootCompleteReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving
        // an Intent broadcast.
        if(Intent.ACTION_BOOT_COMPLETED.equals(intent.getAction())){
            Intent thisIntent = new Intent(context, MainActivity.class);
            thisIntent.setAction("android.intent.action.MAIN");
            thisIntent.addCategory("android.intent.category.LAUNCHER");
            thisIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(thisIntent);
        }
    }
}

2、在AndroidManifest.xml文件中设置接收开机广播权限

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

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" /> 

   <!-- .接收启动完成的广播权限 -->
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:installLocation="internalOnly"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.Light.NoActionBar">
        <receiver
            android:name=".detail.BootCompleteReceiver"
            android:enabled="true"
            android:exported="true">

            <!--接收启动完成的广播-->
            <intent-filter android:priority="1000">
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>

        </receiver>

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".detail.Activity" />
        <activity android:name=".detail.AuthActivity" />

    </application>

</manifest>