我一直在开发一个非常基本的应用程序,用于发送通知。我收到此错误,我也不知道为什么。我看过每个关于堆栈溢出的类似问题,但没有任何效果。我已经重新安装并更新了.gradle文件,更改了依赖关系并切换了即时运行。
我正在尝试使用NotificationChannel,但找不到该库。
这是我的build.gradle(:app)
apply plugin: 'com.android.application'
android {
compileSdkVersion 29
buildToolsVersion "29.0.3"
defaultConfig {
applicationId "com.example.labdirectreplynotification"
minSdkVersion 16
targetSdkVersion 29
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test.ext:junit:1.1.1'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
}
以及发生错误的位置
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
nMgr = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
createNotificationChannel(chID, "My News", "Example Direct Reply Notification");
}
private void createNotificationChannel(String id, String name, String desc) {
NotificationChannel ch = new NotificationChannel(id, name, NotificationManager.IMPORTANCE_HIGH);
ch.setDescription(desc); ch.enableLights(true); ch.setLightColor(Color.RED);
ch.enableVibration(true);
ch.setVibrationPattern(new long[] {100,200,300,400,500,400,300,200,400});
nMgr.createNotificationChannel(ch);
processInlineReply();
}
和错误
java.lang.NoClassDefFoundError: Failed resolution of: Landroid/app/NotificationChannel;
at com.example.labdirectreplynotification.MainActivity.createNotificationChannel(MainActivity.java:40)
at com.example.labdirectreplynotification.MainActivity.onCreate(MainActivity.java:32)
at android.app.Activity.performCreate(Activity.java:6877)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3209)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3352)
at android.app.ActivityThread.access$1100(ActivityThread.java:223)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1797)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7231)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: java.lang.ClassNotFoundException: Didn't find class "android.app.NotificationChannel" on path: DexPathList[[zip file "/data/app/com.example.labdirectreplynotification-1/base.apk"],nativeLibraryDirectories=[/data/app/com.example.labdirectreplynotification-1/lib/arm64, /vendor/lib64, /system/lib64]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
at com.example.labdirectreplynotification.MainActivity.createNotificationChannel(MainActivity.java:40)
at com.example.labdirectreplynotification.MainActivity.onCreate(MainActivity.java:32)
at android.app.Activity.performCreate(Activity.java:6877)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1136)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3209)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3352)
at android.app.ActivityThread.access$1100(ActivityThread.java:223)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1797)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7231)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Suppressed: java.lang.ClassNotFoundException: android.app.NotificationChannel
at java.lang.Class.classForName(Native Method)
at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
... 15 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available