Flutter FAQ

# macOS 安装 imagemagick
brew install imagemagick --with-librsvg

# 使用指定的图像和目录
# 默认会使用 logo.svg 并输出到当前目录
mkdir out
./gen.sh logo.png out

#!/bin/sh

SIZES=${SIZES:-"20x1 20x2 20x3 29x1 29x2 29x3 40x1 40x2 40x3 60x2 60x3 76x1 76x2 83.5x2 1024x1"}
PREFIX=${PREFIX:-"Icon-App"}
source=${1:-logo.svg}
dst=${2:-.}
for s in $SIZES;do
  size=${s%x*}
  scale=${s##*x}
  resize=$(bc <<< ${size}*${scale} )
  out=$dst/"$PREFIX-${size}x${size}@${scale}x.png"
  echo Generate $out
  convert $CONVERT_EXTRA "$source" -resize ${resize}x${resize}     -unsharp 1x4 $out
done

# 通过 logo 生成闪屏资源
# -background none 暴露 svg 的透明
CONVERT_EXTRA="-background none" PREFIX=LaunchImage SIZES="120x1 120x2 120x3" ./gen.sh logo2.svg out/
# 拷贝生成的 LaunchImage*.png 到 ios/Runner/Assets.xcassets/LaunchImage.imageset
# 并修改 Contents.json 指向正确的文件

var localImageConfiguration = createLocalImageConfiguration(context);
new AssetImage('assets/slides/2.png').resolve(localImageConfiguration);
new AssetImage('assets/slides/3.png').resolve(localImageConfiguration);

// unfocus
// https://github.com/flutter/flutter/issues/7247
FocusScope.of(context).requestFocus(new FocusNode());

// 不滚动
ListView(
  physics: const NeverScrollableScrollPhysics()
)

Listener(
    onPointerUp: (e) {
        print("onPointerUp");
    },
    child: GestureDetector(
        onTap: _onTap,
        onLongPress: _onLongPress,
        child: CircleAvatar(
            radius: 30.0,
            backgroundColor: Colors.white,
        ),
    ),
);

Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/copy.py", line 52, in <module>
    import weakref
  File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/weakref.py", line 14, in <module>
    from _weakref import (
ImportError: cannot import name _remove_dead_weakref

brew uninstall --ignore-dependencies python@2

/usr/bin/xcrun simctl list --json devices | grep state