Re: Qam Channels List By Zip Code
Sanora Ngueyn
Flutter's builtin platform-specific API support doesn't rely on code generation, but rather on a flexible message passing style. Alternatively, you can use the Pigeon package for sending structured typesafe messages with code generation:
This guide addresses using the platform channel mechanism if you need to use the platform's APIs in a non-Dart language. But you can also write platform-specific Dart code in your Flutter app by inspecting the defaultTargetPlatform property. Platform adaptations lists some platform-specific adaptations that Flutter automatically performs for you in the framework.
Even though Flutter sends messages to and from Dart asynchronously, whenever you invoke a channel method, you must invoke that method on the platform's main thread. See the section on threading for more information.
On the client side, MethodChannel enables sending messages that correspond to method calls. On the platform side, MethodChannel on Android (MethodChannelAndroid) and FlutterMethodChannel on iOS (MethodChanneliOS) enable receiving method calls and sending back a result. These classes allow you to develop a platform plugin with very little 'boilerplate' code.
The standard platform channels use a standard message codec that supports efficient binary serialization of simple JSON-like values, such as booleans, numbers, Strings, byte buffers, and Lists and Maps of these (see StandardMessageCodec for details). The serialization and deserialization of these values to and from messages happens automatically when you send and receive values.
The following code demonstrates how to call a platform-specific API to retrieve and display the current battery level. It uses the Android BatteryManager API, the iOS device.batteryLevel API, the Windows GetSystemPowerStatus API, and the Linux UPower API with a single platform message, getBatteryLevel().
The example adds the platform-specific code inside the main app itself. If you want to reuse the platform-specific code for multiple apps, the project creation step is slightly different (see developing packages), but the platform channel code is still written in the same way.
The client and host sides of a channel are connected through a channel name passed in the channel constructor. All channel names used in a single app must be unique; prefix the channel name with a unique 'domain prefix', for example: samples.flutter.dev/battery.
Finally, complete the setMethodCallHandler() method added earlier. You need to handle a single platform method, getBatteryLevel(), so test for that in the call argument. The implementation of this platform method calls the Android code written in the previous step, and returns a response for both the success and error cases using the result argument. If an unknown method is called, report that instead.
Finally, complete the setMethodCallHandler() method added earlier. You need to handle a single platform method, getBatteryLevel(), so test for that in the call argument. The implementation of this platform method calls the iOS code written in the previous step. If an unknown method is called, report that instead.
Finally, complete the setMethodCallHandler() method added earlier. You need to handle a single platform method, getBatteryLevel(), so test for that in the call argument. The implementation of this platform method calls the iOS code written in the previous step, and returns a response for both the success and error cases using the result argument. If an unknown method is called, report that instead.
Finally, complete the setMethodCallHandler() method added earlier. You need to handle a single platform method, getBatteryLevel(), so test for that in the call argument. The implementation of this platform method calls the Windows code written in the previous step. If an unknown method is called, report that instead.
Finally, complete the setMethodCallHandler method added earlier. You need to handle a single platform method, getBatteryLevel(), so test for that in the call argument. The implementation of this platform method calls the macOS code written in the previous step. If an unknown method is called, report that instead.
Start by opening the Linux host portion of your Flutter app in the editor of your choice. The instructions below are for Visual Studio Code with the "C/C++" and "CMake" extensions installed, but can be adjusted for other IDEs.
Finally, add the battery_method_call_handler function referenced in the earlier call to fl_method_channel_set_method_call_handler. You need to handle a single platform method, getBatteryLevel, so test for that in the method_call argument. The implementation of this function calls the Linux code written in the previous step. If an unknown method is called, report that instead.
The previous example uses MethodChannel to communicate between the host and client, which isn't typesafe. Calling and receiving messages depends on the host and client declaring the same arguments and datatypes in order for messages to work. You can use the Pigeon package as an alternative to MethodChannel to generate code that sends messages in a structured, typesafe manner.
With Pigeon, the messaging protocol is defined in a subset of Dart that then generates messaging code for Android, iOS, macOS, or Windows. You can find a more complete example and more information on the pigeon page on pub.dev.
Using Pigeon eliminates the need to match strings between host and client for the names and datatypes of messages. It supports: nested classes, grouping messages into APIs, generation of asynchronous wrapper code and sending messages in either direction. The generated code is readable and guarantees there are no conflicts between multiple clients of different versions. Supported languages are Objective-C, Java, Kotlin, C++, and Swift (with Objective-C interop).
If you expect to use your platform-specific code in multiple Flutter apps, you might consider separating the code into a platform plugin located in a directory outside your main application. See developing packages for details.
Besides the above mentioned MethodChannel, you can also use the more basic BasicMessageChannel, which supports basic, asynchronous message passing using a custom message codec. You can also use the specialized BinaryCodec, StringCodec, and JSONMessageCodec classes, or create your own codec.
When invoking channels on the platform side destined for Flutter, invoke them on the platform's main thread. When invoking channels in Flutter destined for the platform side, either invoke them from any Isolate that is the root Isolate, or that is registered as a background Isolate. The handlers for the platform side can execute on the platform's main thread or they can execute on a background thread if using a Task Queue. You can invoke the platform side handlers asynchronously and on any thread.
On Android, the platform's main thread is sometimes called the "main thread", but it is technically defined as the UI thread. Annotate methods that need to be run on the UI thread with @UiThread. On iOS, this thread is officially referred to as the main thread.
To comply with channels' UI thread requirement, you might need to jump from a background thread to Android's UI thread to execute a channel method. In Android, you can accomplish this by post()ing a Runnable to Android's UI thread Looper, which causes the Runnable to execute on the main thread at the next opportunity.
To comply with channel's main thread requirement, you might need to jump from a background thread to iOS's main thread to execute a channel method. You can accomplish this in iOS by executing a block on the main dispatch queue:
I have called and talked to a technician. He was unable to explain to me why I was receiving a code 771 for some channels and not other channels. The station I wanted had the code 771. I checked and there were stations I was receiving and other stations that I was not. I do not understand why I could get some channels and could not get others. To me it should be an all or nothing situation. Which if this were the case I would not be writing. Since I could get some and not others I want to know why. If I get a signal from the one and only that I receive from satellite, then I should have all channels. The technician DID NOT get the job done.
Different channels come from different transponders and different satellites (standard definition programming vs high definition programming) 32 transponders on each satellite even and odd, so it's very possible to lose signal on some channels but not all, the channels that lost signal are either from an even transponder or an odd transponder. Signal loss from an even transponder usually indicates a cabling issue signal loss from an odd transponder indicates an lnb problem. Did you do a signal test at all?
When the weather moved out I again received a signal. I believe to follow your instructions would not answer my question now. I am not understanding why this did not effect all channels at the time it occurred. I was receiving some channels. My past experience was that all channels would be lost, not a few or some. Because of the necessity of getting the satellite dish pointed in an exact direction I am assuming the signal came from a single satellite. If I am receiving signals from different satellites then I might understand the 771 code. Because of the distances involved I believe the space between the signals at rain storm level still could not be far enough apart to both not be affected.
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