Question

我最近将Android Studio更新为2.3，并将gradle更新为2.3.0。自上次我的应用程序正常工作以来，我没有做任何其他更改，但现在每当执行这行代码时：

ViewDataBinding viewDataBinding = DataBindingUtil.setContentView(this,R.layout.main_activity);

我收到此错误：

java.lang.NoClassDefFoundError: android.databinding.DataBinderMapper
     at android.databinding.DataBindingUtil.<clinit>(DataBindingUtil.java:31)
     at com.app.MainActivity.onCreate(MainActivitiy.java:108)
     at android.app.Activity.performCreate(Activity.java:5426)
     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2269)
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
     at android.app.ActivityThread.access$900(ActivityThread.java:161)
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
     at android.os.Handler.dispatchMessage(Handler.java:102)
     at android.os.Looper.loop(Looper.java:157)
     at android.app.ActivityThread.main(ActivityThread.java:5356)
     at java.lang.reflect.Method.invokeNative(Native Method)
     at java.lang.reflect.Method.invoke(Method.java:515)
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
     at dalvik.system.NativeStart.main(Native Method)

根据this SO回答，包含support-v4 r21的gradle依赖项是个问题。事实证明，我的依赖包括那个，但不是因为我添加了依赖，而是因为我添加了：

dataBinding {
    enabled = true
}

因此，我发现这些依赖项已添加到我的项目中：

+--- com.android.databinding:library:1.3.1
|    +--- com.android.support:support-v4:21.0.3 -> 24.0.0 (*)
|    \--- com.android.databinding:baseLibrary:2.3.0-dev -> 2.3.0
+--- com.android.databinding:baseLibrary:2.3.0
\--- com.android.databinding:adapters:1.3.1
     +--- com.android.databinding:library:1.3 -> 1.3.1 (*)
     \--- com.android.databinding:baseLibrary:2.3.0-dev -> 2.3.0

正如您所见，com.android.databinding:library:1.3.1包含support-v4:21.0.3。

这是我的完整模块build.gradle文件：

apply plugin: 'com.android.application'
apply plugin: 'realm-android'

android {
    compileSdkVersion 23
    buildToolsVersion '25.0.0'
    defaultConfig {
        applicationId "com.app"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 12
        versionName "0.2.1"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
        debug {
            debuggable true
        }
    }
    dataBinding {
        enabled = true
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:23.2.1'
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:support-v4:23.2.1'
    compile 'com.android.support:recyclerview-v7:23.2.1'
    compile 'com.android.volley:volley:1.0.0'
    compile 'io.realm:android-adapters:1.3.0'
    compile 'joda-time:joda-time:2.9.4'
    compile 'com.android.volley:volley:1.0.0'
    compile 'com.google.code.gson:gson:2.6.2'
    compile 'com.google.android.gms:play-services-ads:9.8.0'
}

我知道如何解决这个问题吗？

java.lang.NoClassDefFoundError：android.databinding.DataBinderMapper

0 个答案: