Android 后台启动Activity适配

在Android 9及以下版本，后台启动Activity相对自由，但是如果在Activity上下文之外启动Activity会有限制。

Calling startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK flag

所以此时需要给intent添加flag：FLAG_ACTIVITY_NEW_TASK。

在Android版本10及以后版本， 引入了后台执行限制，限制了应用在后台执行操作的能力。非核心任务的后台启动 Activity 可能会受到限制。详情可参见官方文档：从后台启动 Activity 的限制。

根据文档可知，大致有两种方案可实现从后台启动Activity。

方案一：设置全屏Notification

设置Notification时通过setFullScreenIntent添加一个全屏Intent对象，可以在Android 10上从后台启动一个Activity界面，需要在Manifest.xml清单文件中加上：

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

示例代码如下：

private fun getChannelNotificationQ(context: Context, title: String?, content: String?): Notification {val fullScreenPendingIntent = PendingIntent.getActivity(context,0,DemoActivity.genIntent(context),PendingIntent.FLAG_UPDATE_CURRENT)val notificationBuilder = NotificationCompat.Builder(context, ID).setSmallIcon(R.drawable.ic_launcher_foreground).setContentTitle(title).setContentText(content).setPriority(NotificationCompat.PRIORITY_MAX).setCategory(Notification.CATEGORY_CALL).setOngoing(true).setFullScreenIntent(fullScreenPendingIntent, true)return notificationBuilder.build()}

方案二：获取SYSTEM_ALERT_WINDOW权限

如果用户已向应用授予SYSTEM_ALERT_WINDOW权限，则可以在后台启动Activity。在 Android 10 Go 版本中，应用已经无法直接获得SYSTEM_ALERT_WINDOW权限。不过Android引入了一种称为"Display over other apps"（在其他应用上层显示）的新权限体系。这种新的权限体系允许应用请求"TYPE_APPLICATION_OVERLAY"类型的窗口权限。申请步骤如下：

在Manifest.xml清单文件中加上：

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

代码中发起请求权限申请：

if (!Settings.canDrawOverlays(this)) {Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);intent.setData(Uri.parse("package:" + getPackageName()));startActivityForResult(intent, 0);
}

定制化ROM新权限

有些机型增加了一项权限——后台弹出界面，比如在华为、 小米等设备上便新增了这项权限，且默认是关闭的，除非加入了它们的白名单。而且如果权限是关闭的，那么前面所说的两种方案将无效。所以在这些机型上，必须获取后台弹出界面权限，才能够从后台启动Activity。

判断是否获取弹出界面权限：

object PopBackgroundPermissionUtil {private const val TAG = "PopPermissionUtil"private const val HW_OP_CODE_POPUP_BACKGROUND_WINDOW = 100000private const val XM_OP_CODE_POPUP_BACKGROUND_WINDOW = 10021/*** 是否有后台弹出页面权限*/fun hasPopupBackgroundPermission(): Boolean {if (isHuawei()) {return checkHwPermission()}if (isXiaoMi()) {return checkXmPermission()}if (isVivo()) {checkVivoPermission()}if (isOppo() && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {return Settings.canDrawOverlays(sContext)}return true}fun isHuawei(): Boolean {return checkManufacturer("huawei")}fun isXiaoMi(): Boolean {return checkManufacturer("xiaomi")}fun isOppo(): Boolean {return checkManufacturer("oppo")}fun isVivo(): Boolean {return checkManufacturer("vivo")}private fun checkManufacturer(manufacturer: String): Boolean {return manufacturer.equals(Build.MANUFACTURER, true)}private fun checkHwPermission(): Boolean {val context = sContexttry {val c = Class.forName("com.huawei.android.app.AppOpsManagerEx")val m = c.getDeclaredMethod("checkHwOpNoThrow",AppOpsManager::class.java,Int::class.javaPrimitiveType,Int::class.javaPrimitiveType,String::class.java)val result = m.invoke(c.newInstance(),*arrayOf(context.getSystemService(Context.APP_OPS_SERVICE) as AppOpsManager,HW_OP_CODE_POPUP_BACKGROUND_WINDOW,Binder.getCallingUid(),context.packageName)) as IntLog.d(TAG,"PopBackgroundPermissionUtil checkHwPermission result:" + (AppOpsManager.MODE_ALLOWED == result))return AppOpsManager.MODE_ALLOWED == result} catch (e: Exception) {//ignore}return false}private fun checkXmPermission(): Boolean {val context = sContextval ops = context.getSystemService(Context.APP_OPS_SERVICE) as AppOpsManagertry {val method = ops.javaClass.getMethod("checkOpNoThrow", *arrayOf<Class<*>?>(Int::class.javaPrimitiveType, Int::class.javaPrimitiveType, String::class.java))val result = method.invoke(ops,XM_OP_CODE_POPUP_BACKGROUND_WINDOW,Process.myUid(),context.packageName) as IntLog.d(TAG,"PopBackgroundPermissionUtil checkXmPermission result:" + (AppOpsManager.MODE_ALLOWED == result))return result == AppOpsManager.MODE_ALLOWED} catch (e: Exception) {//ignore}return false}private fun checkVivoPermission(): Boolean {val context = sContextval uri =Uri.parse("content://com.vivo.permissionmanager.provider.permission/start_bg_activity")val selection = "pkgname = ?"val selectionArgs = arrayOf(context.packageName)var result = 1val contentResolver = context.contentResolvertry {contentResolver.query(uri, null, selection, selectionArgs, null).use { cursor ->if (cursor!!.moveToFirst()) {result = cursor.getInt(cursor.getColumnIndex("currentstate"))}}} catch (exception: Exception) {//ignore}Log.d(TAG,"PopBackgroundPermissionUtil checkVivoPermission result:" + (AppOpsManager.MODE_ALLOWED == result))return result == AppOpsManager.MODE_ALLOWED}}

跳转弹出界面权限界面：

class SystemAlertWindow(private val mSource: Activity) {fun start(requestCode: Int) {var intent: Intent?intent = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (MARK.contains("meizu")) {meiZuApi(mSource)} else {MdefaultApi(mSource)}} else {if (MARK.contains("huawei")) {huaweiApi(mSource)} else if (MARK.contains("xiaomi")) {xiaomiApi(mSource)} else if (MARK.contains("oppo")) {oppoApi(mSource)} else if (MARK.contains("vivo")) {vivoApi(mSource)} else if (MARK.contains("meizu")) {meizuApi(mSource)} else {LdefaultApi(mSource)}}try {mSource.startActivityForResult(intent, requestCode)} catch (e: Exception) {intent = appDetailsApi(mSource)mSource.startActivityForResult(intent, requestCode)}}private fun huaweiApi(context: Context): Intent? {val intent = Intent()intent.setClassName("com.huawei.systemmanager","com.huawei.permissionmanager.ui.MainActivity")if (hasActivity(context, intent)) {return intent}intent.setClassName("com.huawei.systemmanager","com.huawei.systemmanager.addviewmonitor.AddViewMonitorActivity")if (hasActivity(context, intent)) {return intent}intent.setClassName("com.huawei.systemmanager","com.huawei.notificationmanager.ui.NotificationManagmentActivity")return if (hasActivity(context, intent)) {intent} else MdefaultApi(context)}private fun xiaomiApi(context: Context): Intent? {val intent = Intent("miui.intent.action.APP_PERM_EDITOR")intent.putExtra("extra_pkgname", context.packageName)if (hasActivity(context, intent)) {return intent}intent.setClassName("com.miui.securitycenter","com.miui.permcenter.permissions.AppPermissionsEditorActivity")return if (hasActivity(context, intent)) {intent} else MdefaultApi(context)}private fun oppoApi(context: Context): Intent? {val intent = Intent()intent.putExtra("packageName", context.packageName)intent.setClassName("com.color.safecenter","com.color.safecenter.permission.floatwindow.FloatWindowListActivity")if (hasActivity(context, intent)) {return intent}intent.setClassName("com.coloros.safecenter","com.coloros.safecenter.sysfloatwindow.FloatWindowListActivity")if (hasActivity(context, intent)) {return intent}intent.setClassName("com.oppo.safe", "com.oppo.safe.permission.PermissionAppListActivity")return if (hasActivity(context, intent)) {intent} else MdefaultApi(context)}private fun vivoApi(context: Context): Intent? {val intent = Intent()intent.setClassName("com.iqoo.secure","com.iqoo.secure.ui.phoneoptimize.FloatWindowManager")intent.putExtra("packagename", context.packageName)if (hasActivity(context, intent)) {return intent}intent.setClassName("com.iqoo.secure","com.iqoo.secure.safeguard.SoftPermissionDetailActivity")return if (hasActivity(context, intent)) {intent} else MdefaultApi(context)}private fun meizuApi(context: Context): Intent? {val intent = Intent("com.meizu.safe.security.SHOW_APPSEC")intent.putExtra("packageName", context.packageName)intent.component = ComponentName("com.meizu.safe", "com.meizu.safe.security.AppSecActivity")return if (hasActivity(context, intent)) {intent} else MdefaultApi(context)}companion object {private val MARK = Build.MANUFACTURER.lowercase(Locale.getDefault())const val REQUEST_OVERLY = 7562private fun LdefaultApi(context: Context): Intent {val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS)intent.data = Uri.fromParts("package", context.packageName, null)return intent}private fun appDetailsApi(context: Context): Intent {val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS)intent.data = Uri.fromParts("package", context.packageName, null)return intent}private fun MdefaultApi(context: Context): Intent? {var intent: Intent? = nullif (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {intent = Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION)}intent!!.data = Uri.fromParts("package", context.packageName, null)return if (hasActivity(context, intent)) {intent} else appDetailsApi(context)}private fun meiZuApi(context: Context): Intent? {val intent = Intent("com.meizu.safe.security.SHOW_APPSEC")intent.putExtra("packageName", context.packageName)intent.setClassName("com.meizu.safe", "com.meizu.safe.security.AppSecActivity")return if (hasActivity(context, intent)) {intent} else MdefaultApi(context)}private fun hasActivity(context: Context, intent: Intent?): Boolean {val packageManager = context.packageManagerreturn packageManager.queryIntentActivities(intent!!,PackageManager.MATCH_DEFAULT_ONLY).size > 0}}
}

权限说明

“Draw Over Other Apps”（在其他应用上层绘制）权限：

这个权限允许应用在其他应用的上层绘制悬浮窗口，例如悬浮通知、悬浮工具栏、聊天头像等。通过这个权限，应用可以在其他应用的界面上显示自己的内容，但是这些窗口通常会有一定的限制，不会覆盖系统级别的UI元素（如状态栏、导航栏等）。

“Background Pop-ups”（后台弹窗）权限：

这个权限控制应用在后台是否允许弹出窗口，即使应用处于后台运行状态。这意味着即使应用不在前台，它仍然可以显示一些弹窗、通知或者提醒。这可以让应用在后台运行时继续向用户展示重要的信息。

总结

• 先判断是否是特殊机型，如果是则需要申请后台弹出界面权限
• 如果不是特殊机型，则有两种方案，一是全屏通知，二是申请在其他应用上层绘制权限