Flutter资源加载
- assets
- fonts
iconfont.ttf
- img
- 2.0x
- 3.0x
wechat.png
图片
所有图片按照倍率的不同，存放在不同的文件夹内，在 pubspec.yaml 中这样引用
flutter:
# To add assets to your application, add an assets section, like this:
assets:
- assets/img/
- assets/img/2.0x/
- assets/img/3.0x/
为了方便在代码中引用图片资源，我们生成一个 R.dart 资源文件
class R {
static final String assetsImgWechat = 'assets/img/wechat';
}
之后在代码里可以直接使用：
Image.asset(R.assetsImgWechat, width: 100.0)
图片处理脚本
// Copyright 2018 DebuggerX <dx8917312@gmail.com>. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:io';
var preview_server_port = 2227;
void main() async {
generatorByAssets();
}
void generatorByAssets() async {
var directory = new Directory("assets/img");
var newLines = <String>[];
var varNames = <String>[];
var resource = <String>[];
if (directory.existsSync()) {
var list = directory.listSync(recursive: false);
for (var file in list) {
if (new File(file.path).statSync().type == FileSystemEntityType.file &&
!file.path.contains('.DS_Store')) {
if (file.path.contains('@2x')) {
var newpath = file.path.replaceAll('assets/img', 'assets/img/2.0x');
newpath = newpath.replaceAll('@2x', '');
var f = File(file.path);
f.copySync(newpath);
file.delete();
continue;
}
if (file.path.contains('@3x')) {
var newpath = file.path.replaceAll('assets/img', 'assets/img/3.0x');
newpath = newpath.replaceAll('@3x', '');
var f = File(file.path);
f.copySync(newpath);
file.delete();
continue;
}
var path = file.path.replaceAll('\\', '/');
var varName = path
.replaceAll('-', '_')
.replaceAll('/', '_')
.replaceAll('.png', '')
.replaceAll('.jpg', '')
.replaceAll('.jpeg', '')
.toLowerCase();
var pos = 0;
String char;
while (true) {
pos = varName.indexOf('_', pos);
if (pos == -1) break;
char = varName.substring(pos + 1, pos + 2);
varName = varName.replaceFirst('_$char', '_${char.toUpperCase()}');
pos++;
}
varName = varName.replaceAll('_', '');
resource.add("static final String $varName = '$path';");
varNames.add(" $varName,");
newLines.add(' - $path');
}
}
} else {
throw new FileSystemException('Directory wrong');
}
var r = new File('lib/common/r.dart');
if (r.existsSync()) {
r.deleteSync();
}
r.createSync();
var content = 'class R {\n';
for (var line in resource) {
content = '$content $line\n';
}
content = '$content}';
// content = '$content\n static final values = [\n';
// for (var line in varNames) {
// content = '$content$line\n';
// }
// content = '$content ];\n}\n';
r.writeAsStringSync(content);
}
void generatorByPubspec() async {
bool working = false;
var pubSpec = new File('pubspec.yaml');
var pubLines = pubSpec.readAsLinesSync();
var newLines = <String>[];
var varNames = <String>[];
var resource = <String>[];
for (var line in pubLines) {
if (line.contains('begin') &&
line.contains('#') &&
line.contains('assets')) {
working = true;
newLines.add(line);
}
if (line.contains('end') && line.contains('#') && line.contains('assets'))
working = false;
if (working) {
if (line.trim().startsWith('#') && line.trim().endsWith('*')) {
newLines.add(line);
var directory =
new Directory(line.replaceAll('#', '').replaceAll('*', '').trim());
if (directory.existsSync()) {
var list = directory.listSync(recursive: true);
for (var file in list) {
if (new File(file.path).statSync().type ==
FileSystemEntityType.file) {
var path = file.path.replaceAll('\\', '/');
var varName =
path.replaceAll('/', '_').replaceAll('.', '_').toLowerCase();
var pos = 0;
String char;
while (true) {
pos = varName.indexOf('_', pos);
if (pos == -1) break;
char = varName.substring(pos + 1, pos + 2);
varName =
varName.replaceFirst('_$char', '_${char.toUpperCase()}');
pos++;
}
varName = varName.replaceAll('_', '');
resource
.add("/// ");
resource.add("static final String $varName = '$path';");
varNames.add(" $varName,");
newLines.add(' - $path');
}
}
} else {
throw new FileSystemException('Directory wrong');
}
}
} else {
newLines.add(line);
}
}
var r = new File('lib/r.dart');
if (r.existsSync()) {
r.deleteSync();
}
r.createSync();
var content = 'class R {\n';
for (var line in resource) {
content = '$content $line\n';
}
content = '$content\n static final values = [\n';
print(content);
for (var line in varNames) {
content = '$content $line\n';
}
content = '$content ];\n}\n';
r.writeAsStringSync(content);
var spec = '';
for (var line in newLines) {
spec = '$spec$line\n';
}
pubSpec.writeAsStringSync(spec);
var ser;
try {
ser = await HttpServer.bind('127.0.0.1', preview_server_port);
print('成功启动图片预览服务器于本机<$preview_server_port>端口');
ser.listen(
(req) {
var index = req.uri.path.lastIndexOf('.');
var subType = req.uri.path.substring(index + 1);
print(subType);
req.response
..headers.contentType = new ContentType('image', subType)
..add(new File('.${req.uri.path}').readAsBytesSync())
..close();
},
);
} catch (e) {
print('图片预览服务器已启动或端口被占用');
}
}
Font
-
导入字体图标文件；这一步和导入字体文件相同，假设我们的字体图标文件保存在项目根目录下，路径为"fonts/iconfont.ttf"：
fonts: - family: myIcon #指定一个字体名 fonts: - asset: fonts/iconfont.ttf -
为了使用方便，我们定义一个MyIcons类，功能和Icons类一样：将字体文件中的所有图标都定义成静态变量：
class MyIcons{ // book 图标 static const IconData book = const IconData( 0xe614, fontFamily: 'myIcon', matchTextDirection: true ); // 微信图标 static const IconData wechat = const IconData( 0xec7d, fontFamily: 'myIcon', matchTextDirection: true ); } -
使用
Row( mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ Icon(MyIcons.book,color: Colors.purple,), Icon(MyIcons.wechat,color: Colors.green,), ], )
