一，依赖冲突
All com.android.support libraries must use the exact same version specification (mixing versions can lead to runtime crashes). Found versions 28.0.0, 27.1.1. Examples include com.android.support:animated-vector-drawable:28.0.0 and com.android.support:recyclerview-v7:27.1.1 less... (Ctrl+F1)
There are some combinations of libraries, or tools and libraries, that are incompatible, or can lead to bugs. One such incompatibility is compiling with a version of the Android support libraries that is not the latest version (or in particular, a version lower than your targetSdkVersion).
当我们使用android studio添加一些第三方的依赖库时，很可能会提示上面这个错误。
大致意思就是com.android.support的包版本号要保持一致，但是可能我们自己新建的项目的com.android.support包版本号要高一些，一些第三方的库的com.android.support可能没有及时更新support库，就会出现这个错误。
解决方法（同样的适用于其他的依赖冲突。）
解决方法：
在其存在冲突的module中的build.gradle文件中加入下面代码，原理就是通过遍历所有依赖，并修改指定库的版本号
其中
requested.group == ‘com.android.support‘ com.android.support表示要修改的依赖库
details.useVersion ‘28.0.0‘ 28.0.0表示要修改的版本号
android {
compileSdkVersion 28
defaultConfig {
applicationId "cn.ktc.tvmeeting"
minSdkVersion 21
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile(‘proguard-android-optimize.txt‘), ‘proguard-rules.pro‘
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
configurations.all {
resolutionStrategy.eachDependency { DependencyResolveDetails details ->
def requested = details.requested
if (requested.group == ‘com.android.support‘) {
if (!requested.name.startsWith("multidex")) {
details.useVersion ‘28.0.0‘
}
}
}
}
}