Android-閱讀類內部的build.gradle屬性

Question

我希望可以訪問build.gradle屬性，以便可以自動執行我的應用程序中的某些流程。

這是我目前的結構：

rootProject / build.gradle

buildscript {
    ext {
        buildTools = "25.0.2"
        minSdk = 16
        compileSdk = 23
        targetSdk = 23

        versions = [supportLib         : '25.0.0',
                    multidex           : '1.0.1',
                    playServices       : '10.0.1']
        libs = [appcompat            : "com.android.support:appcompat-v7:$versions.supportLib",
               design               : "com.android.support:design:$versions.supportLib"]

        .... Other libraries and setup....

    }
}

rootProject / app / build.gradle

...
dependencies {
    // Support libraries
    compile libs.appcompat
    compile libs.design
    .....
}

我想同時在Java和build.gradle上訪問屬性版本和libs變量。 我該如何實現？

Answer 1

使用gradle.properties文件僅在一個位置定義值，然后可以在gradle項目配置中使用此值。

然后，要能夠在Java android代碼中訪問這些值，請使用“ buildConfigField”定義。

gradle.properties

values=value1,value2

build.gradle

def String[] valuesArray = values.split(',')

android {
    defaultConfig {
        buildConfigField "String[]", "VALUES_ARRAY", "{" +
                "\"" + valuesArray[0] + "\"," +
                "\"" + valuesArray[1] + "\"" +
                "}"
    }
}

在java文件中

BuildConfig.VALUES_ARRAY

Answer 2

您可以執行類似操作，但是在buildscript塊之外

ext {
    // Version
    supportVersion = '26.0.0'

    // Support Libraries dependencies
    supportDependencies = [
            design:            "com.android.support:design:${supportVersion}",
            recyclerView:      "com.android.support:recyclerview-v7:${supportVersion}",
            cardView:          "com.android.support:cardview-v7:${supportVersion}",
            appCompat:         "com.android.support:appcompat-v7:${supportVersion}",
            supportAnnotation: "com.android.support:support-annotations:${supportVersion}",
    ]

    firebaseVersion = '11.0.2';

    firebaseDependencies = [
            core:         "com.google.firebase:firebase-core:${firebaseVersion}",
            database:     "com.google.firebase:firebase-database:${firebaseVersion}",
            storage:      "com.google.firebase:firebase-storage:${firebaseVersion}",
            crash:        "com.google.firebase:firebase-crash:${firebaseVersion}",
            auth:         "com.google.firebase:firebase-auth:${firebaseVersion}",
            messaging:    "com.google.firebase:firebase-messaging:${firebaseVersion}",
            remoteConfig: "com.google.firebase:firebase-config:${firebaseVersion}",
            invites:      "com.google.firebase:firebase-invites:${firebaseVersion}",
            adMod:        "com.google.firebase:firebase-ads:${firebaseVersion}",
            appIndexing:  "com.google.android.gms:play-services-appindexing:${firebaseVersion}",
    ];
}


// Module build file
dependencies {
    // ...
    compile supportDependencies.appCompat
    compile supportDependencies.design
    compile firebaseDependencies.crash
}

在Java中，您無法訪問build.gradle文件，因為它們僅在構建時使用。 但是，您可以將相同的值放在BuildConfig文件中。 在此文件中，有一些預先構建的值，例如BuildConfig.VERSION_NAME或者您可以使用一些自定義鍵，例如：

android {
    ...
    defaultConfig {
        ...
        // defining the build date
        buildConfigField "long", "BUILD_DATE", System.currentTimeMillis() + "L"
        // define whether this build is a production build
        buildConfigField "boolean", "IS_PRODUCTION", "false"
        // note that to define a string you need to escape it
        buildConfigField "String", "API_KEY", "\"my_api_key\""
    }
}

自動生成的<package_name>.BuildConfig.java將基於上述指令包含以下字段：

public class BuildConfig {
    // ... other generated fields ...
    public static final long BUILD_DATE = 1469504547000L;
    public static final boolean IS_PRODUCTION = false;
    public static final String API_KEY = "my_api_key";
}