Android资源编译失败：属性缺少Android命名空间前缀

Question

我刚做了一个新项目。这是一个干净的项目，但是运行它时出现错误。我从我的 ic_launcher_background.xml 中收到了此错误，“ Android资源编译失败 C：\ Users \ Acer \ AndroidStudioProjects \ eStall \ app \ src \ main \ res \ drawable \ ic_launcher_background.xml：144：错误：格式不正确（无效的令牌）。“

当我查看ic_launcher_background.xml代码时，发现此错误， “属性缺少Android名称空间前缀” 。修复了在显示此Android资源编译失败错误之前，colors.xml中的错误。

是因为将3.3版（我认为）更新到3.4版吗？

ic_launcher_background.xml

    <?xml version="1.0" encoding="UTF-8"?>
<project version="4">
    <component name="AndroidLayouts">
        <shared>
            <config>
                <device id="pixel_xl" />
            </config>
        </shared>
    </component>
    <component name="AndroidLogFilters">
        <option
            name="TOOL_WINDOW_CONFIGURED_FILTER"
            value="Show only selected application" />
    </component>
    <component name="ChangeListManager">
        <list
            name="Default Changelist"
            comment=""
            default="true"
            id="a49e748a-44a5-45ea-b600-8c3086397541" />
        <option
            name="EXCLUDED_CONVERTED_TO_IGNORED"
            value="true" />
        <option
            name="SHOW_DIALOG"
            value="false" />
        <option
            name="HIGHLIGHT_CONFLICTS"
            value="true" />
        <option
            name="HIGHLIGHT_NON_ACTIVE_CHANGELIST"
            value="false" />
        <option
            name="LAST_RESOLUTION"
            value="IGNORE" />
    </component>
    <component name="ExternalProjectsManager">
        <system id="GRADLE">
            <state>
                <projects_view />
            </state>
        </system>
    </component>
    <component name="FUSProjectUsageTrigger">
        <session id="1505037262">
            <usages-collector id="statistics.lifecycle.project">
                <counts>
                    <entry
                        key="project.closed"
                        value="4" />
                    <entry
                        key="project.open.time.15"
                        value="1" />
                    <entry
                        key="project.open.time.18"
                        value="1" />
                    <entry
                        key="project.open.time.20"
                        value="1" />
                    <entry
                        key="project.open.time.25"
                        value="1" />
                    <entry
                        key="project.open.time.26"
                        value="1" />
                    <entry
                        key="project.open.time.6"
                        value="1" />
                    <entry
                        key="project.opened"
                        value="6" />
                </counts>
            </usages-collector>
            <usages-collector id="statistics.file.extensions.open">
                <counts>
                    <entry
                        key="gradle"
                        value="2" />
                    <entry
                        key="java"
                        value="1" />
                    <entry
                        key="xml"
                        value="3" />
                </counts>
            </usages-collector>
            <usages-collector id="statistics.file.types.open">
                <counts>
                    <entry
                        key="Groovy"
                        value="2" />
                    <entry
                        key="JAVA"
                        value="1" />
                    <entry
                        key="XML"
                        value="3" />
                </counts>
            </usages-collector>
            <usages-collector id="statistics.file.extensions.edit">
                <counts>
                    <entry
                        key="gradle"
                        value="1" />
                    <entry
                        key="txt"
                        value="19" />
                    <entry
                        key="xml"
                        value="295" />
                </counts>
            </usages-collector>
            <usages-collector id="statistics.file.types.edit">
                <counts>
                    <entry
                        key="Groovy"
                        value="1" />
                    <entry
                        key="PLAIN_TEXT"
                        value="19" />
                    <entry
                        key="XML"
                        value="295" />
                </counts>
            </usages-collector>
        </session>
    </component>
    <component name="FileEditorManager">
        <leaf SIDE_TABS_SIZE_LIMIT_KEY="300">
            <file
                current-in-tab="true"
                pinned="false">
                <entry file="file://$PROJECT_DIR$/app/src/main/res/layout/activity_main.xml">
                    <provider
                        editor-type-id="text-editor"
                        selected="true">
                        <state relative-caret-position="1020">
                            <caret
                                line="60"
                                selection-end-line="60"
                                selection-start-line="60" />
                        </state>
                    </provider>
                    <provider editor-type-id="android-designer2" />
                </entry>
            </file>
        </leaf>
    </component>
    <component name="IdeDocumentHistory">
        <option name="CHANGED_PATHS">
            <list>
                <option value="$PROJECT_DIR$/app/build.gradle" />
                <option value="$PROJECT_DIR$/app/src/main/res/layout/activity_main.xml" />
            </list>
        </option>
    </component>
    <component
        name="ProjectFrameBounds"
        extendedState="6">
        <option
            name="x"
            value="858" />
        <option
            name="y"
            value="-13" />
        <option
            name="width"
            value="980" />
        <option
            name="height"
            value="1040" />
    </component>
    <component name="ProjectView">
        <navigator
            proportions=""
            version="1">
            <foldersAlwaysOnTop value="true" />
        </navigator>
        <panes>
            <pane id="AndroidView">
                <subPane>
                    <expand>
                        <path>
                            <item
                                name="eStall"
                                type="1abcf292:AndroidViewProjectNode" />
                            <item
                                name="Gradle Scripts"
                                type="ae0cef3a:AndroidBuildScriptsGroupNode" />
                        </path>
                    </expand>
                    <select />
                </subPane>
            </pane>
            <pane id="ProjectPane" />
            <pane id="PackagesPane" />
            <pane id="Scope" />
        </panes>
    </component>
    <component name="PropertiesComponent">
        <property
            name="android.sdk.path"
            value="$USER_HOME$/AppData/Local/Android/Sdk" />
        <property
            name="device.picker.selection"
            value="Android_Accelerated_x86_Oreo" />
        <property
            name="settings.editor.selected.configurable"
            value="AndroidSdkUpdater" />
    </component>
    <component name="RecentsManager">
        <key name="android.template.packageName">
            <recent name="com.example.estall" />
        </key>
        <key name="android.template.parentActivityClass">
            <recent name="" />
        </key>
    </component>