在Android 9及以下版别,后台发动Activity相对自在,可是假如在Activity上下文之外发动Activity会有约束。

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版别10及今后版别, 引入了后台履行约束,约束了使用在后台履行操作的才能。非中心使命的后台发动 Activity 可能会受到约束。详情可参见官方文档:从后台发动 Activity 的约束。

依据文档可知,大致有两种计划可实现从后台发动Activity。

计划一:设置全屏Notification

设置Notification时经过setFullScreenIntent添加一个全屏Intent目标,能够在Android 10上从后台发动一个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()
    }
计划二:获取SYSTEM_ALERT_WINDOW权限

假如用户已向使用授予SYSTEM_ALERT_WINDOW权限,则能够在后台发动Activity。在 Android 10 Go 版别中,使用现已无法直接获得SYSTEM_ALERT_WINDOW权限。不过Android引入了一种称为”Display over other apps”(在其他使用上层显现)的新权限系统。这种新的权限系统答应使用请求”TYPE_APPLICATION_OVERLAY”类型的窗口权限。请求过程如下:

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请求:

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,且默认是封闭的,除非加入了它们的白名单。而且假如权限是封闭的,那么前面所说的两种计划将无效。所以在这些机型上,有必要获取后台弹出界面权限,才能够从后台发动Activity。

判别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 = 100000
    private 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 = sContext
        try {
            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 Int
            Log.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 = sContext
        val ops = context.getSystemService(Context.APP_OPS_SERVICE) as AppOpsManager
        try {
            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 Int
            Log.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 = sContext
        val uri =
            Uri.parse("content://com.vivo.permissionmanager.provider.permission/start_bg_activity")
        val selection = "pkgname = ?"
        val selectionArgs = arrayOf(context.packageName)
        var result = 1
        val contentResolver = context.contentResolver
        try {
            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 = 7562
        private 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? = null
            if (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.packageManager
            return packageManager.queryIntentActivities(
                intent!!,
                PackageManager.MATCH_DEFAULT_ONLY
            ).size > 0
        }
    }
}
权限说明

“Draw Over Other Apps”(在其他使用上层制作)权限:

这个权限答应使用在其他使用的上层制作悬浮窗口,例如悬浮告诉、悬浮工具栏、聊天头像等。经过这个权限,使用能够在其他使用的界面上显现自己的内容,可是这些窗口通常会有必定的约束,不会掩盖系统等级的UI元素(如状态栏、导航栏等)。

“Background Pop-ups”(后台弹窗)权限:

这个权限控制使用在后台是否答应弹出窗口,即便使用处于后台运转状态。这意味着即便使用不在前台,它依然能够显现一些弹窗、告诉或许提示。这能够让使用在后台运转时持续向用户展现重要的信息。

总结
  • 先判别是否是特殊机型,假如是则需要请求后台弹出界面权限
  • 假如不是特殊机型,则有两种计划,一是全屏告诉,二是请求在其他使用上层制作权限