text stringlengths 1 474 |
|---|
use dart:developer Timeline utilities.Wrap the code you want to measure in Timeline methods. |
<code_start>import 'dart:developer'; |
void main() { |
Timeline.startSync('interesting function'); |
// iWonderHowLongThisTakes(); |
Timeline.finishSync(); |
}<code_end> |
To ensure that the runtime performance characteristics closely match that |
of your final product, run your app in profile mode.<topic_end> |
<topic_start> |
Add performance overlay |
info Note |
You can toggle display of the performance overlay on |
your app using the Performance Overlay button in the |
Flutter inspector. If you prefer to do it in code, |
use the following instructions.To enable the PerformanceOverlay widget in your code, |
set the showPerformanceOverlay property to true on the |
MaterialApp, CupertinoApp, or WidgetsApp |
constructor:<topic_end> |
<topic_start>Example 10 |
<code_start>import 'package:flutter/material.dart'; |
class MyApp extends StatelessWidget { |
const MyApp({super.key}); |
@override |
Widget build(BuildContext context) { |
return MaterialApp( |
showPerformanceOverlay: true, |
title: 'My Awesome App', |
theme: ThemeData( |
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple), |
), |
home: const MyHomePage(title: 'My Awesome App'), |
); |
} |
}<code_end> |
(If you’re not using MaterialApp, CupertinoApp, |
or WidgetsApp, you can get the same effect by wrapping your |
application in a stack and putting a widget on your stack that was |
created by calling PerformanceOverlay.allEnabled().)To learn how to interpret the graphs in the overlay, |
check out The performance overlay in |
Profiling Flutter performance.<topic_end> |
<topic_start> |
Add widget alignment grid |
To add an overlay to a Material Design baseline grid on your app to |
help verify alignments, add the debugShowMaterialGrid argument in the |
MaterialApp constructor.To add an overlay to non-Material applications, add a GridPaper widget. |
<topic_end> |
<topic_start>Use a native language debugger |
info Note |
This guide presumes you understand general debugging, |
have installed Flutter and git, and have familiarity |
with the Dart language as well as one of the following |
languages: Java, Kotlin, Swift, or Objective-C.If you write Flutter apps only with Dart code, |
you can debug your code using your IDE’s debugger. |
The Flutter team recommends VS Code.If you write a platform-specific plugin or |
use platform-specific libraries, you can debug |
that portion of your code with a native debugger.This guide shows you how you can connect two |
debuggers to your Dart app, one for Dart, and one for the native code.<topic_end> |
<topic_start> |
Debug Dart code |
This guide describes how to use VS Code to debug your Flutter app. |
You can also use your preferred IDE with the |
Flutter and Dart plugins installed and configured.<topic_end> |
<topic_start> |
Debug Dart code using VS Code |
The following procedure explains how to use the Dart debugger |
with the default sample Flutter app. |
The featured components in VS Code work and appear when |
debugging your own Flutter project as well.Create a basic Flutter app.Open the lib\main.dart file in the Flutter app using |
VS Code.Click the bug icon |
(). |
This opens the following panes in VS Code:The first time you run the debugger takes the longest.Test the debugger.a. In main.dart, click on this line:b. Press Shift + F9. |
This adds a breakpoint where the |
_counter variable increments.c. In the app, click the + button |
to increment the counter. The app pauses.d. At this point, VS Code displays:<topic_end> |
<topic_start> |
VS Code Flutter debugger |
The Flutter plugin for VS Code adds a number of components |
to the VS Code user interface.<topic_end> |
<topic_start>Changes to VS Code interface |
When launched, the Flutter debugger adds debugging tools to the |
VS Code interface.The following screenshot and table explain the purpose of each tool.To change where the panel (in orange) appears in VS Code, |
go to View > Appearance > Panel Position.<topic_end> |
<topic_start>VS Code Flutter debugging toolbar |
The toolbar allows you to debug using any debugger. |
You can step in, out, and over Dart statements, hot reload, or resume the app.<topic_end> |
<topic_start> |
Update test Flutter app |
For the remainder of this guide, you need to update the |
test Flutter app. This update adds native code to debug.Open the lib/main.dart file using your preferred IDE.Replace the contents of main.dart with the following code. |
<code_start>// Copyright 2023 The Flutter Authors. All rights reserved. |
// Use of this source code is governed by a BSD-style license that can be |
// found in the LICENSE file. |
import 'package:flutter/material.dart'; |
import 'package:url_launcher/url_launcher.dart'; |
void main() { |
runApp(const MyApp()); |
} |
class MyApp extends StatelessWidget { |
const MyApp({super.key}); |
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