Android 开机自启动

首先实现开机自启动：

第一步创建一个广播接收者，如MyBootBroadcastReceiver.java

package com.example;

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

public class MyBootBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Intent startServiceIntent = new Intent(context, MyService.class);
        context.startService(startServiceIntent);
	//启动应用
	//Intent intent = getPackageManager().getLaunchIntentForPackage(packageName);
	//context.startActivity(intent);
    }
}

第二步给receiver配置对应intent-filter

<receiver android:name="MyBootBroadcastReceiver">  
    <intent-filter>  
        <action android:name="android.intent.action.BOOT_COMPLETED" />  
    </intent-filter>  
</receiver>

第三步添加权限，缺少这步则无法在Android 3.0及其之前版本上自启动

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

上面的实现有以下【限制】：

1.由于Android系统在外置SD卡加载前广播ACTION_BOOT_COMPLETED，于是如果应用安装在外置SD卡上，它无法接收到此广播，原文见Broadcast Receivers listening for "boot completed"。

2.从Android 3.1（API level和对应NDK版本）开始，系统的包管理器保持跟踪处于停止状态(stopped state)的应用程序，提供了一种控制其从后台进程和其它应用程序启动的方式。这种停止状态的应用程序指那些安装了但从未启动过的apk，或被用户在程序管理中force stop的apk。Android系统为防止广播无意或不必要开启停止状态的组件，它给所有广播intent添加了FL​​AG_EXCLUDE_STOPPED_PACKAGES标志（不设置和同FLAG_INCLUDE_STOPPED_PACKAGES一起设置结果都是此标志），

Intent.java

public boolean isExcludingStopped() {
        return (mFlags&(FLAG_EXCLUDE_STOPPED_PACKAGES|FLAG_INCLUDE_STOPPED_PACKAGES))
                == FLAG_EXCLUDE_STOPPED_PACKAGES;
    }

IntentResolver.java

/**
     * Returns whether the object associated with the given filter is
     * "stopped," that is whether it should not be included in the result
     * if the intent requests to excluded stopped objects.
     */
    protected boolean isFilterStopped(F filter, int userId) {
        return false;
    }

private void buildResolveList(Intent intent, FastImmutableArraySet<String> categories,
            boolean debug, boolean defaultOnly,
            String resolvedType, String scheme, F[] src, List<R> dest, int userId) {
        ...

        final boolean excludingStopped = intent.isExcludingStopped();

        final int N = src != null ? src.length : 0;
        boolean hasNonDefaults = false;
        int i;
        F filter;
        for (i=0; i<N && (filter=src[i]) != null; i++) {
            int match;
            if (debug) Slog.v(TAG, "Matching against filter " + filter);

            if (excludingStopped && isFilterStopped(filter, userId)) {
                if (debug) {
                    Slog.v(TAG, "  Filter's target is stopped; skipping");
                }
                continue;
            }
	...

此标志指广播intent排除停止状态的应用，原文见Launch controls on stopped applications。用户可以给自己的应用或者后台服务添加FLAG_INCLUDE_STOPPED_PACKAGES标志以唤醒停止状态的应用，但系统自带的广播intent，用户无法修改，只能接受；注意系统级应用都不是停止状态。

PackageManagerService.java中重写IntentResolver

final class ActivityIntentResolver
            extends IntentResolver<PackageParser.ActivityIntentInfo, ResolveInfo> {
	...
@Override
        protected boolean isFilterStopped(PackageParser.ActivityIntentInfo filter, int userId) {
            if (!sUserManager.exists(userId)) return true;
            PackageParser.Package p = filter.activity.owner;
            if (p != null) {
                PackageSetting ps = (PackageSetting)p.mExtras;
                if (ps != null) {
                    // System apps are never considered stopped for purposes of
                    // filtering, because there may be no way for the user to
                    // actually re-launch them.
                    return (ps.pkgFlags&ApplicationInfo.FLAG_SYSTEM) == 0
                            && ps.getStopped(userId);
                }
            }
            return false;
        }

private final class ServiceIntentResolver
            extends IntentResolver<PackageParser.ServiceIntentInfo, ResolveInfo> {
	...
@Override
        protected boolean isFilterStopped(PackageParser.ServiceIntentInfo filter, int userId) {
            if (!sUserManager.exists(userId)) return true;
            PackageParser.Package p = filter.service.owner;
            if (p != null) {
                PackageSetting ps = (PackageSetting)p.mExtras;
                if (ps != null) {
                    // System apps are never considered stopped for purposes of
                    // filtering, because there may be no way for the user to
                    // actually re-launch them.
                    return (ps.pkgFlags & ApplicationInfo.FLAG_SYSTEM) == 0
                            && ps.getStopped(userId);
                }
            }
            return false;
        }

于是把apk安装在root过的手机中的/system/app下面就能实现apk开机自启动。

最后禁止开机自启动，参考文章android手机root后的安全问题 （四）。