I have tried everything I could find from StackOverflow to make this problem right but none of them succeeded.

The strange thing is : I can use lambda such as

 activity.runOnUiThread(() -> {
                    activity.startActivity(intent);
                });

and stream like this

activity.getPackageManager().getInstalledPackages(0).stream().collect(Collectors.toList())

but this will fail :

activity.getPackageManager()
.getInstalledPackages(0)
.stream()
.filter(e -> e.packageName.contains("com"))
.collect(Collectors.toList())

my build.gradle file:

plugins {
    id 'com.android.application'
}

android {
    compileSdk 31

    defaultConfig {
        applicationId "com.mylearn.simplesender"
        minSdk 25
        targetSdk 31
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

    buildFeatures {
        viewBinding true
    }


    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {
    implementation 'androidx.recyclerview:recyclerview:1.0.0'
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation group: 'com.squareup.okhttp3', name: 'okhttp', version: '4.9.2'
    implementation group: 'com.alibaba', name: 'fastjson', version: '1.2.78'
    implementation group: 'com.google.guava', name: 'guava', version: '31.0.1-android'
    implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.12.0'
    testImplementation 'junit:junit:4. '
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

and also, here is my Gradle setting in Android Studio

here is my compile setting in Android Studio

It shows an unreadable error, and when I debug this expression in the watcher shows :

Compilation failed:
-source 1.6 中不支持 lambda 表达式
  (请使用 -source 8 或更高版本以启用 lambda 表达式)

which means I'm using source version 1.6, and it does not support lambda expression and told me to use source 8 or higher to enable lambda expression.

But I'm already in java 11, how could this happen?

CodePudding user response：

go to App level build.gradle>

then put this code in android {} block

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

after this your code look like this

android {
compileSdkVersion 31
buildToolsVersion "30.0.2"

defaultConfig {
    applicationId "in.chikuai.example"
    minSdkVersion 19
    targetSdkVersion 31
    versionCode 1
    versionName "1.0"

    testInstrumentationRunner "androidx.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
}

}

CodePudding user response：

Recently, I have the problem solved by change my build.gradle file according to the