Test drive

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小牛编辑

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2023-12-01

This page describes how to create a new Flutter app from templates, run it, and experience “hot reload” after you make changes to the app.

Select your development tool of choice for writing, building, and running Flutter apps.

Create the app

Select File > New Flutter Project.
Select Flutter application as the project type, and press Next.
Make sure that the Flutter SDK Path text field specifies the location of the SDK. Install the SDK if you haven’t yet done so.
Enter a project name (for example, myapp), and press Next.
Click Finish.
Wait for Android Studio to install the SDK, and create the project.

The above commands create a Flutter project directory called myapp that contains a simple demo app that uses Material Components.

Run the app

Locate the main Android Studio toolbar:
In the target selector, select an Android device for running the app. If none are listed as available, select Tools> Android > AVD Manager and create one there. For details, see Managing AVDs.
Click the run icon in the toolbar, or invoke the menu item Run > Run.

After the app build completes, you’ll see the starter app on your device.

Try hot reload

Flutter offers a fast development cycle with hot reload, the ability to reload the code of a live running app without restarting or losing app state. Make a change to app source, tell your IDE or command-line tool that you want to hot reload, and see the change in your simulator, emulator, or device.

Open lib/main.dart.

Change the string

'You have pushed the button this many times'

'You have clicked the button this many times'

Save your changes: invoke Save All, or click Hot Reload .

You’ll see the updated string in the running app almost immediately.

Create the app

Invoke View > Command Palette.
Type “flutter”, and select the Flutter: New Project.
Enter a project name, such as myapp, and press Enter.
Create or select the parent directory for the new project folder.
Wait for project creation to complete and the main.dart file to appear.

The above commands create a Flutter project directory called myapp that contains a simple demo app that uses Material Components.

Run the app

Locate the VS Code status bar (the blue bar at the bottom of the window):
Select a device from the Device Selector area. For details, see Quickly switching between Flutter devices.
- If no device is available and you want to use a device simulator, click No Devices and launch a simulator.
- To setup a real device, follow the device-specific instructions on the Install page for your OS.
Invoke Debug > Start Debugging or press F5.
Wait for the app to launch — progress is printed in the Debug Console view.

After the app build completes, you’ll see the starter app on your device.

Try hot reload

Open lib/main.dart.

Change the string

'You have pushed the button this many times'

'You have clicked the button this many times'

Save your changes: invoke File > Save All, or click Hot Reload (the green circular arrow button).

You’ll see the updated string in the running app almost immediately.

Create the app

Use the flutter create command to create a new project:

$ flutter create myapp
$ cd myapp

The command creates a Flutter project directory called myapp that contains a simple demo app that uses Material Components.

Run the app

Check that an Android device is running. If none are shown, follow the device-specific instructions on the Install page for your OS.
```
$ flutter devices
```
Run the app with the following command:
```
$ flutter run
```

After the app build completes, you’ll see the starter app on your device.

Try hot reload

Open lib/main.dart.

Change the string

'You have pushed the button this many times'

'You have clicked the button this many times'

Save your changes.
Type r in the terminal window.

You’ll see the updated string in the running app almost immediately.

Next step

You’ll next learn some core Flutter concepts by creating a small app.