Question

我正在检查特定时间间隔内的更新。每当更新失败时，我都会显示一个带有错误通知的窗口。问题是每次创建一个新窗口。

我已经尝试过

let window = null;

if(window === null) {
    window = new BrowserWindow();
    window.loadURL('notification.html');
}

else {
    window.restore(); // But that is only for minimizing
    // WHAT DO I PUT HERE?
}

Answer 1

自Electron 5.0.x起，单实例API发生了更改。您可以通过这种方式使用它。

<?xml version="1.0" encoding="utf-8"?>
<!-- <?xml-stylesheet type="text/xsl" href="FieldBasedDisplay.xslt"?> -->
<!--Copyright 2016 Bluetooth SIG, Inc. All rights reserved.-->
<Characteristic xsi:noNamespaceSchemaLocation="http://schemas.bluetooth.org/Documents/characteristic.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Cycling Power Feature" type="org.bluetooth.characteristic.cycling_power_feature" uuid="2A65" last-modified="2016-05-03" approved="Yes">
  <InformativeText>
    <Summary>The CP Feature characteristic is used to report a list of features supported by the device.</Summary>
  </InformativeText>
  <Value>
    <Field name="Cycling Power Feature">
      <Requirement>Mandatory</Requirement>
      <Format>32bit</Format>
      <BitField>
        <Bit index="0" size="1" name="Pedal Power Balance Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="1" size="1" name="Accumulated Torque Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="2" size="1" name="Wheel Revolution Data Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="3" size="1" name="Crank Revolution Data Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="4" size="1" name="Extreme Magnitudes Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="5" size="1" name="Extreme Angles Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="6" size="1" name="Top and Bottom Dead Spot Angles Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="7" size="1" name="Accumulated Energy Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="8" size="1" name="Offset Compensation Indicator Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="9" size="1" name="Offset Compensation Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="10" size="1" name="Cycling Power Measurement Characteristic Content Masking Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="11" size="1" name="Multiple Sensor Locations Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="12" size="1" name="Crank Length Adjustment Supported ">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="13" size="1" name="Chain Length Adjustment Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="14" size="1" name="Chain Weight Adjustment Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="15" size="1" name="Span Length Adjustment Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="16" size="1" name="Sensor Measurement Context">
          <Enumerations>
            <Enumeration key="0" value="Force based" />
            <Enumeration key="1" value="Torque based" />
          </Enumerations>
        </Bit>
        <Bit index="17" size="1" name="Instantaneous Measurement Direction Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="18" size="1" name="Factory Calibration Date Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="19" size="1" name="Enhanced Offset Compensation Supported">
          <Enumerations>
            <Enumeration key="0" value="False" />
            <Enumeration key="1" value="True" />
          </Enumerations>
        </Bit>
        <Bit index="20" size="2" name="Distribute System Support">
          <Enumerations>
            <Enumeration key="0" value="Unspecified (legacy sensor)" />
            <Enumeration key="1" value="Not for use in a distributed system" />
            <Enumeration key="2" value="Can be used in a distributed system" />
            <Enumeration key="3" value="RFU" />
          </Enumerations>
        </Bit>
        <ReservedForFutureUse index="22" size="10" />
      </BitField>
    </Field>
  </Value>
  <Note>        
        The fields in the above table, reading from top to bottom, are shown in the order of LSO to MSO, where LSO = Least Significant Octet and MSO = Most Significant Octet. 
        The Least Significant Octet represents the eight bits numbered 0 to 7.
    </Note>
</Characteristic>

Answer 2

app.requestSingleInstanceLock()
app.on('second-instance', (event, argv, cwd) => {
  /* print some msg or sth */
})

引用https://electronjs.org/docs/api/app#event-second-instance

Answer 3

因此，我有另一个用于设置的窗口和一个从菜单中打开该窗口的按钮，因此，如果用户单击菜单中的该按钮，它将一次又一次地打开多个实例。

10单击= 10个实例设置窗口。

所以我确实遵循了其他解决方案。

不知道这是否是最好的方法，我也在学习。

let settingsWindow;

const createSettingsWindow = () => {

    if (!settingsWindow) {// If not already opened
              settingsWindow = new BrowserWindow({
                  width: 500,
                  height: 400,
              })
              settingsWindow.loadURL(url.format({
                  pathname: path.join(__dirname, "./src/setting.html"),
                  protocol: 'file',
                  slashes: true,
                  resizable: false,
              }))
              settingsWindow.on("closed", () => {
                settingsWindow = null;
              })
    } 
    else {
        //Handle Behaviour When Opening again from the menu.
        console.log("Dont Open another instance of about window.")
    }
}

现在，当用户单击菜单中的设置按钮时，它将在控制台中显示Dont Open another instance of about window。

如何在Electron中防止窗口的多个实例？

3 个答案: