Pythonでjsonファイルを読み書き

qt_fontdialog_json.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# -*- mode: python;Encoding: utf8n -*-

"""
PyQt + FontDialog + json のテスト

ラベルのフォントを、
フォント選択ダイアログで選択したフォントに変更して、
フォント種類をjsonファイルに記録する。

英数字のフォント名も、日本語フォント名も、jsonファイルに記録できる。
"""

import os
import sys
from PyQt4 import QtGui
import codecs
import json

JSON_FILE = "settings_font.json"

DEF_STR = "The quick brown fox jumps over a lazy dog.\n" \
          u"いろはにほへと　ちりぬるを"


class Example(QtGui.QWidget):

    def __init__(self):
        super(Example, self).__init__()
        self.initUI()

    def initUI(self):
        """UIの初期化"""
        vbox = QtGui.QVBoxLayout()
        btn = QtGui.QPushButton('Dialog', self)
        btn.setSizePolicy(QtGui.QSizePolicy.Fixed, QtGui.QSizePolicy.Fixed)
        btn.move(20, 20)
        vbox.addWidget(btn)
        btn.clicked.connect(self.showDialog)

        self.lbl = QtGui.QLabel(DEF_STR, self)
        self.lbl.move(130, 20)
        vbox.addWidget(self.lbl)

        self.lbl2 = QtGui.QLabel("", self)
        self.lbl2.move(130, 60)
        vbox.addWidget(self.lbl2)

        self.setLayout(vbox)
        self.setGeometry(300, 300, 250, 180)
        self.setWindowTitle('Font dialog')
        self.show()

        # open json file
        self.json_path = os.path.join(os.path.dirname(__file__), JSON_FILE)
        self.json_dic = self.read_json(self.json_path)

        # 前回終了時のフォント種類が記録されていたら再現する
        font = self.get_font_from_json(self.json_dic)
        if font is None:
            print "font is None"
        else:
            self.lbl.setFont(font)

    def showDialog(self):
        """フォント選択ダイアログの表示"""
        font, ok = QtGui.QFontDialog.getFont(self.lbl.font())
        if ok:
            self.lbl.setFont(font)      # Widgetのフォントを変更
            font_name = unicode(font.toString())
            self.lbl2.setText(font_name)

            # JSON用辞書に記録
            self.set_font_to_json(font)
            self.write_json(self.json_path, self.json_dic)

    def set_font_to_json(self, font):
        """json用辞書にフォント種類を記録"""
        self.json_dic['fontrawname'] = unicode(font.rawName())
        self.json_dic['fontpointsize'] = font.pointSize()
        self.json_dic['fontweight'] = font.weight()
        self.json_dic['fontitalic'] = 1 if font.italic() else 0
        self.json_dic['fontfixed'] = 1 if font.fixedPitch() else 0
        self.json_dic['fontpointsizef'] = font.pointSizeF()

    def get_font_from_json(self, json_dic):
        """json用辞書を元にフォント種類を取得"""
        if 'fontrawname' in json_dic:
            rawname = json_dic['fontrawname']
            if rawname == "":
                return None
            else:
                font = QtGui.QFont(rawname)
                if 'fontweight' in json_dic:
                    font.setWeight(json_dic['fontweight'])
                if 'fontpointsize' in json_dic:
                    font.setPointSize(json_dic['fontpointsize'])
                if 'fontitalic' in json_dic:
                    fg = True if json_dic['fontitalic'] == 1 else False
                    font.setItalic(fg)
                if 'fontfixed' in json_dic:
                    fg = True if json_dic['fontfixed'] == 1 else False
                    font.setFixedPitch(fg)
                return font
        else:
            return None

    def read_json(self, json_path):
        """jsonの読み込み"""
        json_dic = {}
        fg = False
        if os.path.exists(json_path):
            with codecs.open(json_path, 'r', 'utf8') as f:
                try:
                    json_dic = json.load(f)
                    fg = True
                except IOError, inst:
                    sys.stderr.write(str(inst) + "\n")
        if fg:
            return json_dic

        # jsonが読み込めないので初期化と保存をする
        json_dic = {'fontrawname': ''}
        self.write_json(json_path, json_dic)
        return json_dic

    def write_json(self, json_path, json_dic):
        """jsonの保存"""
        fg = False
        with codecs.open(json_path, 'w', 'utf8') as f:
            try:
                json.dump(json_dic, f, ensure_ascii=False,
                          sort_keys=True, indent=4)
                fg = True
            except IOError, inst:
                sys.stderr.write(str(inst) + "\n")

        self.dump_json_file(json_path)
        return fg

    def dump_json_file(self, json_path):
        """jsonファイルの内容をダンプ"""
        with codecs.open(json_path, 'r', 'utf8') as f:
            try:
                print f.read()
            except IOError, inst:
                sys.stderr.write(str(inst) + "\n")


def main():
    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()