在platform --> android目录下找到build.gradle文件，打开并在def promptForReleaseKeyPassword() {...}函数前加入以下内容：
完整报错
BUILD FAILED Total time: 19.142 secs ERROR: In <declare-styleable> FontFamilyFont, unable to find attribute android:ttcIndex FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':processDebugResources'. > com.android.ide.common.process.ProcessException: Failed to execute aapt * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Error: cmd: Command failed with exit code 1 Error output: ERROR: In <declare-styleable> FontFamilyFont, unable to find attribute android:fontVariationSettings ERROR: In <declare-styleable> FontFamilyFont, unable to find attribute android:ttcIndex FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':processDebugResources'. > com.android.ide.common.process.ProcessException: Failed to execute aapt * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. [ERROR] An error occurred while running cordova build android (exit code 1).
解决办法：
执行命令ionic cordova platform add android
在platform --> android目录下找到build.gradle文件，打开并在def promptForReleaseKeyPassword() {...}前加入以下内容：
configurations.all {
resolutionStrategy {
force 'com.android.support:support-v4:27.1.0'
}
}
原因：
compile "com.android.support:support-v4:+" 带+号是指要用最新版本。
force 'com.android.support:support-v4:27.1.0' 添加force强制指定annotations