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it is better to specify these now. They cannot be changed once the app |
is released. Your organization name should be unique.<topic_end> |
<topic_start> |
Opening a project from existing source code |
To open an existing Flutter project:Click Open.error Important |
Do not use the New > Project from existing sources |
option for Flutter projects.<topic_end> |
<topic_start> |
Editing code and viewing issues |
The Flutter plugin performs code analysis that enables the following:<topic_end> |
<topic_start> |
Running and debugging |
info Note |
You can debug your app in a few ways.The instructions below describe features available in Android |
Studio and IntelliJ. For information on launching DevTools, |
see Running DevTools from Android Studio in the |
DevTools docs.Running and debugging are controlled from the main toolbar:<topic_end> |
<topic_start> |
Selecting a target |
When a Flutter project is open in the IDE, you should see a set of |
Flutter-specific buttons on the right-hand side of the toolbar.info Note |
If the Run and Debug buttons are disabled, and no targets are listed, |
Flutter has not been able to discover any connected iOS or |
Android devices or simulators. |
You need to connect a device, or start a simulator, to proceed.<topic_end> |
<topic_start> |
Run app without breakpoints |
<topic_end> |
<topic_start> |
Run app with breakpoints |
<topic_end> |
<topic_start> |
Fast edit and refresh development cycle |
Flutter offers a best-in-class developer cycle enabling you to see the effect |
of your changes almost instantly with the Stateful Hot Reload feature. |
To learn more, check out Hot reload.<topic_end> |
<topic_start> |
Show performance data |
info Note |
To examine performance issues in Flutter, see the |
Timeline view.To view the performance data, including the widget rebuild |
information, start the app in Debug mode, and then open |
the Performance tool window using |
View > Tool Windows > Flutter Performance.To see the stats about which widgets are being rebuilt, and how often, |
click Show widget rebuild information in the Performance pane. |
The exact count of the rebuilds for this frame displays in the second |
column from the right. For a high number of rebuilds, a yellow spinning |
circle displays. The column to the far right shows how many times a |
widget was rebuilt since entering the current screen. |
For widgets that aren’t rebuilt, a solid grey circle displays. |
Otherwise, a grey spinning circle displays.The app shown in this screenshot has been designed to deliver |
poor performance, and the rebuild profiler gives you a clue |
about what is happening in the frame that might cause poor |
performance. The widget rebuild profiler is not a diagnostic |
tool, by itself, about poor performance.The purpose of this feature is to make you aware when widgets are |
rebuilding—you might not realize that this is happening when just |
looking at the code. If widgets are rebuilding that you didn’t expect, |
it’s probably a sign that you should refactor your code by splitting |
up large build methods into multiple widgets.This tool can help you debug at least four common performance issues:The whole screen (or large pieces of it) are built by a single |
StatefulWidget, causing unnecessary UI building. Split up the |
UI into smaller widgets with smaller build() functions.Offscreen widgets are being rebuilt. This can happen, for example, |
when a ListView is nested in a tall Column that extends offscreen. |
Or when the RepaintBoundary is not set for a list that extends |
offscreen, causing the whole list to be redrawn.The build() function for an AnimatedBuilder draws a subtree that |
does not need to be animated, causing unnecessary rebuilds of static |
objects.An Opacity widget is placed unnecessarily high in the widget tree. |
Or, an Opacity animation is created by directly manipulating the |
opacity property of the Opacity widget, causing the widget itself |
and its subtree to rebuild.You can click on a line in the table to navigate to the line |
in the source where the widget is created. As the code runs, |
the spinning icons also display in the code pane to help you |
visualize which rebuilds are happening.Note that numerous rebuilds doesn’t necessarily indicate a problem. |
Typically you should only worry about excessive rebuilds if you have |
already run the app in profile mode and verified that the performance |
is not what you want.And remember, the widget rebuild information is only available in |
a debug build. Test the app’s performance on a real device in a profile |
build, but debug performance issues in a debug build.<topic_end> |
<topic_start> |
Editing tips for Flutter code |
If you have additional tips we should share, let us know!<topic_end> |
<topic_start> |
Assists & quick fixes |
Assists are code changes related to a certain code identifier. |
A number of these are available when the cursor is placed on a |
Flutter widget identifier, as indicated by the yellow lightbulb icon. |
The assist can be invoked by clicking the lightbulb, or by using the |
keyboard shortcut (Alt+Enter on Linux and Windows, |
Option+Return on macOS), as illustrated here:Quick Fixes are similar, only they are shown with a piece of code has an error |
and they can assist in correcting it. They are indicated with a red lightbulb.<topic_end> |
<topic_start>Wrap with new widget assist |
This can be used when you have a widget that you want to wrap in a surrounding |
widget, for example if you want to wrap a widget in a Row or Column.<topic_end> |
<topic_start>Wrap widget list with new widget assist |
Similar to the assist above, but for wrapping an existing list of |
widgets rather than an individual widget.<topic_end> |
<topic_start>Convert child to children assist |
Changes a child argument to a children argument, |
and wraps the argument value in a list.<topic_end> |
<topic_start> |
Live templates |
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