Gradle 秘訣與方法

Gradle 和 Gradle 的 Android 外掛程式提供靈活功能，可用來編譯、建構及封裝 Android 應用程式或程式庫。本頁提供了一些實用提示和設定，協助您充分運用每次建構作業。如要瞭解加快建構速度的方法，請參閱「將建構速度最佳化」。

如果您是第一次使用 Gradle，請參閱「設定建構」瞭解基本方法。您也可以查看 Android 外掛程式的 DSL 參考說明文件，進一步瞭解本頁中使用的屬性。

管理專案和來源

以下設定可管理專案的模組與來源。如要進一步瞭解如何建立及管理專案和模組，請參閱「專案總覽」。

變更預設來源設定

您可以透過 sourceSets在模組層級封鎖build.gradle變更 Gradle 用來收集來源集。

Groovy

android {
  ...
  sourceSets {
    // Encapsulates configurations for the main source set.
    main {
      // Changes the directory for Java sources. The default directory is
      // 'src/main/java'.
      java.srcDirs = ['other/java']

      // When you list multiple directories, Gradle uses all of them to collect
      // sources. You should avoid specifying a directory which is a parent to one
      // or more other directories you specify.
      res.srcDirs = ['other/res1', 'other/res2']

      // For each source set, you can specify only one Android manifest.
      // The following points Gradle to a different manifest for this source set.
      manifest.srcFile 'other/AndroidManifest.xml'
      ...
    }

    // Create additional blocks to configure other source sets.
    androidTest {

      // If all the files for a source set are located under a single root
      // directory, you can specify that directory using the setRoot property.
      // When gathering sources for the source set, Gradle looks only in locations
      // relative to the root directory you specify. For example, after applying
      // the configuration below for the androidTest source set, Gradle looks for
      // Java sources only in the src/tests/java/ directory.
      setRoot 'src/tests'
      ...
    }
  }
}
...

Kotlin

android {
  ...
  sourceSets {
    // Encapsulates configurations for the main source set.
    getByName("main") {
      // Changes the directory for Java sources. The default directory is
      // 'src/main/java'.
      java.setSrcDirs("other/java")

      // When you list multiple directories, Gradle uses all of them to collect
      // sources. You should avoid specifying a directory which is a parent to one
      // or more other directories you specify.
      res.setSrcDirs("other/res1", "other/res2")

      // For each source set, you can specify only one Android manifest.
      // The following points Gradle to a different manifest for this source set.
      manifest.srcFile("other/AndroidManifest.xml")
      ...
    }

    // Create additional blocks to configure other source sets.
    androidTest {

      // If all the files for a source set are located under a single root
      // directory, you can specify that directory using the setRoot property.
      // When gathering sources for the source set, Gradle looks only in locations
      // relative to the root directory you specify. For example, after applying
      // the configuration below for the androidTest source set, Gradle looks for
      // Java sources only in the src/tests/java/ directory.
      setRoot("src/tests")
      ...
    }
  }
}
...

管理程式庫和依附元件

Gradle 提供了一個可管理依附元件的可靠機制，無論所需對像是遠端程式庫或本機程式庫模組。

使用依附元件設定來指定特定建構作業

如果只想為特定的建構變化版本來源集或測試來源集設定依附元件，請將依附元件設定的名稱改為大寫，並加上建構變化版本或測試來源集的名稱做為其前置字串。

Groovy

android {...}

// Creates Gradle dependency configurations to use in the dependencies block.
configurations {
  // For variants that combine a product flavor and build type, you need to
  // intitialize a placeholder for its dependency configuration.
  freeDebugRuntimeOnly{}
  ...
}

dependencies {
    // Adds an implementation dependency only to the "free" product flavor.
    freeImplementation 'com.google.firebase:firebase-ads:21.5.1'
    // Adds a runtimeOnly dependency only to the "freeDebug" build variant.
    freeDebugRuntimeOnly fileTree(dir: 'libs', include: ['*.jar'])
    // Adds a remote binary dependency only for local tests.
    testImplementation 'junit:junit:4.12'
    // Adds a remote binary dependency only for the instrumented test APK.
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.6.1'
}

Kotlin

android {...}

dependencies {
    // Use ""() notation for custom flavors and build types
    // Adds an implementation dependency only to the "free" product flavor.
    "freeImplementation"("com.google.firebase:firebase-ads:21.5.1")
    // Adds a runtimeOnly dependency only to the "freeDebug" build variant.
    "freeDebugRuntimeOnly"(fileTree("dir" to "libs", "include" to "*.jar"))
    // Adds a remote binary dependency only for local tests.
    testImplementation("junit:junit:4.12")
    // Adds a remote binary dependency only for the instrumented test APK.
    androidTestImplementation("com.android.support.test.espresso:espresso-core:3.6.1")
}

建立不同版本的應用程式

Gradle 和 Android 外掛程式可讓您設定建構版本，透過單一模組建立不同版本的應用程式。

設定動態版本代碼

根據預設，Gradle 為專案產生 APK 時，每個 APK 都會有相同的版本資訊，如同模組層級 build.gradle 檔案所指定。由於 Google Play 商店不允許同一個應用程式使用多個全都具有相同版本資訊的 APK，因此您必須確保每個 APK 都有各自專屬的 versionCode，然後再上傳至 Play 商店。

方法是在建構期間透過自訂建構邏輯為每個 APK 指派不同的版本代碼。舉例來說，為各個 ABI 建立個別 APK 時，自動的 APK 版本看起來會像這樣：

Groovy

android {
  ...
  defaultConfig {
    ...
    versionCode 4
  }
  splits {
    ...
  }
}

// Map for the version code that gives each ABI a value.
ext.abiCodes = ['armeabi-v7a':1, mips:2, x86:3]

// For per-density APKs, create a similar map like this:
// ext.densityCodes = ['hdpi': 1, 'xhdpi': 2, 'xxhdpi': 3, 'xxxhdpi': 4]

import com.android.build.OutputFile

// For each APK output variant, override versionCode with a combination of
// ext.abiCodes * 1000 + variant.versionCode. In this example, variant.versionCode
// is equal to defaultConfig.versionCode. If you configure product flavors that
// define their own versionCode, variant.versionCode uses that value instead.
android.applicationVariants.all { variant ->

  // Assigns a different version code for each output APK
  // other than the universal APK.
  variant.outputs.each { output ->

    // Stores the value of ext.abiCodes that is associated with the ABI for this variant.
    def baseAbiVersionCode =
            // Determines the ABI for this variant and returns the mapped value.
            project.ext.abiCodes.get(output.getFilter(OutputFile.ABI))

    // Because abiCodes.get() returns null for ABIs that are not mapped by ext.abiCodes,
    // the following code does not override the version code for universal APKs.
    // However, because we want universal APKs to have the lowest version code,
    // this outcome is desirable.
    if (baseAbiVersionCode != null) {

      // Assigns the new version code to versionCodeOverride, which changes the version code
      // for only the output APK, not for the variant itself. Skipping this step simply
      // causes Gradle to use the value of variant.versionCode for the APK.
      output.versionCodeOverride =
              baseAbiVersionCode * 1000 + variant.versionCode
    }
  }
}

Kotlin

android {
  ...
  defaultConfig {
    ...
    versionCode = 4
  }
  splits {
    ...
  }
}

// Map for the version code that gives each ABI a value.
val abiCodes = mapOf("armeabi-v7a" to 1, "mips" to 2, "x86" to 3)

// For per-density APKs, create a similar map like this:
// val densityCodes = mapOf("hdpi" to 1, "xhdpi" to 2, "xxhdpi" to 3, "xxxhdpi" to 4)

import com.android.build.api.variant.FilterConfiguration.FilterType.*

// For each APK output variant, override versionCode with a combination of
// abiCodes * 1000 + variant.versionCode. In this example, variant.versionCode
// is equal to defaultConfig.versionCode. If you configure product flavors that
// define their own versionCode, variant.versionCode uses that value instead.
androidComponents {
    onVariants { variant ->

        // Assigns a different version code for each output APK
        // other than the universal APK.
        variant.outputs.forEach { output ->
            val name = output.filters.find { it.filterType == ABI }?.identifier

            // Stores the value of abiCodes that is associated with the ABI for this variant.
            val baseAbiCode = abiCodes[name]
            // Because abiCodes.get() returns null for ABIs that are not mapped by ext.abiCodes,
            // the following code does not override the version code for universal APKs.
            // However, because we want universal APKs to have the lowest version code,
            // this outcome is desirable.
            if (baseAbiCode != null) {
                // Assigns the new version code to output.versionCode, which changes the version code
                // for only the output APK, not for the variant itself.
                output.versionCode.set(baseAbiCode * 1000 + (output.versionCode.get() ?: 0))
            }
        }
    }
}

結合多種變種版本

在某些情況下，您可能會想結合多種變種版本的設定。如要這麼做，您可以使用 Gradle 適用的 Android 外掛程式建立多組變種版本 (稱為「版本維度」)。

以下程式碼範例使用 flavorDimensions 屬性建立「mode」版本維度，將「完整版」和「試用版」變種版本分組，以及一個「api」版本維度，依照 API 層級將變種版本設定分組。Gradle 隨後會將「mode」維度的變種版本與「api」維度的組合搭配使用。

Groovy

android {
  ...
  buildTypes {
    debug {...}
    release {...}
  }

  // Specifies the flavor dimensions you want to use. The order in which you
  // list each dimension determines its priority, from highest to lowest,
  // when Gradle merges variant sources and configurations. You must assign
  // each product flavor you configure to one of the flavor dimensions.
  flavorDimensions "api", "mode"

  productFlavors {
    demo {
      // Assigns this product flavor to the "mode" flavor dimension.
      dimension "mode"
      ...
    }

    full {
      dimension "mode"
      ...
    }

    // Configurations in the "api" product flavors override those in "mode"
    // flavors and the defaultConfig block. Gradle determines the priority
    // between flavor dimensions based on the order in which they appear next
    // to the flavorDimensions property above--the first dimension has a higher
    // priority than the second, and so on.
    minApi24 {
      dimension "api"
      minSdkVersion '24'
      // To ensure the target device receives the version of the app with
      // the highest compatible API level, assign version codes in increasing
      // value with API level. To learn more about assigning version codes to
      // support app updates and uploading to Google Play, read Multiple APK Support
      versionCode 30000 + android.defaultConfig.versionCode
      versionNameSuffix "-minApi24"
      ...
    }

    minApi23 {
      dimension "api"
      minSdkVersion '23'
      versionCode 20000  + android.defaultConfig.versionCode
      versionNameSuffix "-minApi23"
      ...
    }

    minApi21 {
      dimension "api"
      minSdkVersion '21'
      versionCode 10000  + android.defaultConfig.versionCode
      versionNameSuffix "-minApi21"
      ...
    }
  }
}
...

Kotlin

android {
  ...
  buildTypes {
    getByName("debug") {...}
    getByName("release") {...}
  }

  // Specifies the flavor dimensions you want to use. The order in which you
  // list each dimension determines its priority, from highest to lowest,
  // when Gradle merges variant sources and configurations. You must assign
  // each product flavor you configure to one of the flavor dimensions.
  flavorDimensions += listOf("api", "mode")

  productFlavors {
    create("demo") {
      // Assigns this product flavor to the "mode" flavor dimension.
      dimension = "mode"
      ...
    }

    create("full") {
      dimension = "mode"
      ...
    }

    // Configurations in the "api" product flavors override those in "mode"
    // flavors and the defaultConfig block. Gradle determines the priority
    // between flavor dimensions based on the order in which they appear next
    // to the flavorDimensions property above--the first dimension has a higher
    // priority than the second, and so on.
    create("minApi24") {
      dimension = "api"
      minSdkVersion(24)
      // To ensure the target device receives the version of the app with
      // the highest compatible API level, assign version codes in increasing
      // value with API level. To learn more about assigning version codes to
      // support app updates and uploading to Google Play, read Multiple APK Support
      versionCode = 30000 + android.defaultConfig.versionCode
      versionNameSuffix = "-minApi24"
      ...
    }

    create("minApi23") {
      dimension = "api"
      minSdkVersion(23)
      versionCode = 20000  + android.defaultConfig.versionCode
      versionNameSuffix = "-minApi23"
      ...
    }

    create("minApi21") {
      dimension = "api"
      minSdkVersion(21)
      versionCode = 10000  + android.defaultConfig.versionCode
      versionNameSuffix = "-minApi21"
      ...
    }
  }
}
...

篩選變化版本

您可以在模組的 build.gradle 檔案中使用 variantFilter 區塊篩選不想要的建構變數。下列程式碼範例會指示 Gradle 不要建構具有「minApi21」和「demo」兩者變種版本的變化版本：

Groovy

android {
  ...
  buildTypes {...}

  flavorDimensions "api", "mode"
  productFlavors {
    demo {...}
    full {...}
    minApi24 {...}
    minApi23 {...}
    minApi21 {...}
  }

  variantFilter { variant ->
      def names = variant.flavors*.name
      // To check for a certain build type, use variant.buildType.name == "<buildType>"
      if (names.contains("minApi21") && names.contains("demo")) {
          // Gradle ignores any variants that satisfy the conditions above.
          setIgnore(true)
      }
  }
}
...

Kotlin

android {
  ...
  buildTypes {...}

  flavorDimensions "api", "mode"
  productFlavors {
    create("demo") {...}
    create("full") {...}
    create("minApi24") {...}
    create("minApi23") {...}
    create("minApi21") {...}
  }
}

androidComponents {
    beforeVariants { variantBuilder ->
        // To check for a certain build type, use variantBuilder.buildType == "<buildType>"
        if (variantBuilder.productFlavors.containsAll(listOf("api" to "minApi21", "mode" to "demo"))) {
            // Gradle ignores any variants that satisfy the conditions above.
            variantBuilder.enabled = false
        }
    }
}
...

測試應用程式

如要進一步瞭解如何執行本機和整合式單元測試，請參閱「測試應用程式」。

設定 Lint 選項

您可以在模組層級 build.gradle 檔案中使用 lintOptions 區塊來設定特定的 Lint 選項。如要進一步瞭解如何為您的 Android 專案執行 Lint，請參閱「使用 Lint 改善程式碼」。

Groovy

android {
    ...
    lintOptions {
        // Turns off checks for the issue IDs you specify.
        disable 'TypographyFractions','TypographyQuotes'
        // Turns on checks for the issue IDs you specify. These checks are in
        // addition to the default lint checks.
        enable 'RtlHardcoded','RtlCompat', 'RtlEnabled'
        // To enable checks for only a subset of issue IDs and ignore all others,
        // list the issue IDs with the 'check' property instead. This property overrides
        // any issue IDs you enable or disable using the properties above.
        checkOnly 'NewApi', 'InlinedApi'
        // If set to true, turns off analysis progress reporting by lint.
        quiet true
        // if set to true (default), stops the build if errors are found.
        abortOnError false
        // if true, only report errors.
        ignoreWarnings true
    }
}
...

Kotlin

android {
    ...
    lintOptions {
        // Turns off checks for the issue IDs you specify.
        disable("TypographyFractions")
        disable("TypographyQuotes")
        // Turns on checks for the issue IDs you specify. These checks are in
        // addition to the default lint checks.
        enable("RtlHardcoded")
        enable("RtlCompat")
        enable("RtlEnabled")
        // To enable checks for only a subset of issue IDs and ignore all others,
        // list the issue IDs with the 'check' property instead. This property overrides
        // any issue IDs you enable or disable using the properties above.
        checkOnly("NewApi", "InlinedApi")
        // If set to true, turns off analysis progress reporting by lint.
        quiet = true
        // if set to true (default), stops the build if errors are found.
        abortOnError = false
        // if true, only report errors.
        ignoreWarnings = true
    }
}
...

設定檢測資訊清單設定

Gradle 建構測試 APK 時，會自動產生 AndroidManifest.xml 檔案，並使用 <instrumentation> 節點進行設定。如要變更這個節點的部分設定，可以在測試來源集中建立另一個資訊清單檔案，或是設定模組層級的 build.gradle 檔案，如以下程式碼範例。

Groovy

android {
  ...
  // Each product flavor you configure can override properties in the
  // defaultConfig block. To learn more, go to Configure Product Flavors.
  defaultConfig {
    ...
    // Specifies the application ID for the test APK.
    testApplicationId "com.test.foo"
    // Specifies the fully-qualified class name of the test instrumentation runner.
    testInstrumentationRunner "android.test.InstrumentationTestRunner"
    // If set to 'true', enables the instrumentation class to start and stop profiling.
    // If set to false (default), profiling occurs the entire time the instrumentation
    // class is running.
    testHandleProfiling true
    // If set to 'true', indicates that the Android system should run the instrumentation
    // class as a functional test. The default value is 'false'
    testFunctionalTest true
  }
}
...

Kotlin

android {
  ...
  // Each product flavor you configure can override properties in the
  // defaultConfig block. To learn more, go to Configure Product Flavors.
  defaultConfig {
    ...
    // Specifies the application ID for the test APK.
    testApplicationId = "com.test.foo"
    // Specifies the fully-qualified class name of the test instrumentation runner.
    testInstrumentationRunner = "android.test.InstrumentationTestRunner"
    // If set to 'true', enables the instrumentation class to start and stop profiling.
    // If set to false (default), profiling occurs the entire time the instrumentation
    // class is running.
    testHandleProfiling = true
    // If set to 'true', indicates that the Android system should run the instrumentation
    // class as a functional test. The default value is 'false'
    testFunctionalTest = true
  }
}
...

變更測試版本類型

根據預設，所有測試都會以偵錯建構類型執行。您可以在模組層級 build.gradle 檔案中使用 testBuildType 屬性，將此類型變更為其他建構類型。 舉例來說，如果您想對「測試」版本類型執行測試，請編輯以下程式碼片段所示的檔案。

Groovy

android {
    ...
    testBuildType "staging"
}

Kotlin

android {
    ...
    testBuildType "staging"
}

設定 Gradle 測試選項

如要指定變更 Gradle 執行所有測試的方式，請在模組層級 build.gradle 中設定 testOptions 區塊。

Groovy

android {
  ...
  // Encapsulates options for running tests.
  testOptions {
    // Changes the directory where Gradle saves test reports. By default, Gradle saves test reports
    // in the path_to_your_project/module_name/build/outputs/reports/ directory.
    // '$rootDir' sets the path relative to the root directory of the current project.
    reportDir "$rootDir/test-reports"
    // Changes the directory where Gradle saves test results. By default, Gradle saves test results
    // in the path_to_your_project/module_name/build/outputs/test-results/ directory.
    // '$rootDir' sets the path relative to the root directory of the current project.
    resultsDir "$rootDir/test-results"
  }
}

Kotlin

android {
  ...
  // Encapsulates options for running tests.
  testOptions {
    // Changes the directory where Gradle saves test reports. By default, Gradle saves test reports
    // in the path_to_your_project/module_name/build/outputs/reports/ directory.
    // '$rootDir' sets the path relative to the root directory of the current project.
    reportDir "$rootDir/test-reports"
    // Changes the directory where Gradle saves test results. By default, Gradle saves test results
    // in the path_to_your_project/module_name/build/outputs/test-results/ directory.
    // '$rootDir' sets the path relative to the root directory of the current project.
    resultsDir "$rootDir/test-results"
  }
}

如果只要指定本機單元測試的選項，請設定 testOptions.unitTests 區塊。

Groovy

android {
  ...
  testOptions {
    ...
    // Encapsulates options for local unit tests.
    unitTests {
      // By default, local unit tests throw an exception any time the code you are testing tries to access
      // Android platform APIs (unless you mock Android dependencies yourself or with a testing
      // framework like Mockito). However, you can enable the following property so that the test
      // returns either null or zero when accessing platform APIs, rather than throwing an exception.
      returnDefaultValues true

      // Encapsulates options for controlling how Gradle executes local unit tests. For a list
      // of all the options you can specify, read Gradle's reference documentation.
      all {
        // Sets JVM argument(s) for the test JVM(s).
        jvmArgs '-XX:MaxPermSize=256m'

        // You can also check the task name to apply options to only the tests you specify.
        if (it.name == 'testDebugUnitTest') {
          systemProperty 'debug', 'true'
        }
      }
    }
  }
}

Kotlin

android {
  ...
  testOptions {
    ...
    // Encapsulates options for local unit tests.
    unitTests {
      // By default, local unit tests throw an exception any time the code you are testing tries to access
      // Android platform APIs (unless you mock Android dependencies yourself or with a testing
      // framework like Mockito). However, you can enable the following property so that the test
      // returns either null or zero when accessing platform APIs, rather than throwing an exception.
      returnDefaultValues true

      // Encapsulates options for controlling how Gradle executes local unit tests. For a list
      // of all the options you can specify, read Gradle's reference documentation.
      all {
        // Sets JVM argument(s) for the test JVM(s).
        jvmArgs '-XX:MaxPermSize=256m'

        // You can also check the task name to apply options to only the tests you specify.
        if (it.name == 'testDebugUnitTest') {
          systemProperty 'debug', 'true'
        }
      }
    }
  }
}

最佳化您的建構作業

本節提供一些設定，協助您更快完成完整版與累加版本。詳情請參閱「最佳化建構速度」。

縮減程式碼

Android Studio 會使用 R8 來存取 ProGuard 規則檔案，進而縮減程式碼。如果是新專案，Android Studio 會使用 Android SDK 的 tools/proguard/folder 的預設設定檔 (proguard-android.txt)。如要進一步縮小程式碼範圍，請試試位於相同位置的 proguard-android-optimize.txt 檔案。

Groovy

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

Kotlin

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

如要新增各建構變化版本專屬的規則，請為每個樣式設定額外的 proguardFiles 屬性。例如，以下範例會將 flavor2-rules.pro 新增至「flavor2」。現在，「flavor2」的發布版本會使用全部三個規則檔案，因為系統也套用了發布區塊中的檔案。

Groovy

android {
  ...
  buildTypes {
    release {
      minifyEnabled true
      proguardFiles getDefaultProguardFile('proguard-android.txt'),
             'proguard-rules.pro'
    }
  }
  productFlavors {
    flavor1 {
      ...
    }
    flavor2 {
      proguardFile 'flavor2-rules.pro'
    }
  }
}
...

Kotlin

android {
  ...
  buildTypes {
    release {
      minifyEnabled true
      proguardFiles getDefaultProguardFile('proguard-android.txt'),
             'proguard-rules.pro'
    }
  }
  productFlavors {
    flavor1 {
      ...
    }
    flavor2 {
      proguardFile 'flavor2-rules.pro'
    }
  }
}
...

發布應用程式

如要進一步瞭解如何將應用程式發布到 Google Play，請參閱「發布應用程式」。

簽署應用程式

雖然 Android Studio 提供簡單的方法，讓您透過 UI 為發布子版本設定簽署，不過您仍可以手動設定模組 build.gradle 檔案中的 signingConfigs 區塊：

Groovy

android {
  ...
  defaultConfig { ... }

  // Encapsulates signing configurations.
  signingConfigs {
    // Creates a signing configuration called "release".
    release {
      // Specifies the path to your keystore file.
      storeFile file("my-release-key.jks")
      // Specifies the password for your keystore.
      storePassword "password"
      // Specifies the identifying name for your key.
      keyAlias "my-alias"
      // Specifies the password for your key.
      keyPassword "password"
    }
  }
  buildTypes {
    release {
      // Adds the "release" signing configuration to the release build type.
      signingConfig signingConfigs.release
      ...
    }
  }
}
...

Kotlin

android {
  ...
  defaultConfig { ... }

  // Encapsulates signing configurations.
  signingConfigs {
    // Creates a signing configuration called "release".
    release {
      // Specifies the path to your keystore file.
      storeFile file("my-release-key.jks")
      // Specifies the password for your keystore.
      storePassword "password"
      // Specifies the identifying name for your key.
      keyAlias "my-alias"
      // Specifies the password for your key.
      keyPassword "password"
    }
  }
  buildTypes {
    release {
      // Adds the "release" signing configuration to the release build type.
      signingConfig signingConfigs.release
      ...
    }
  }
}
...

從專案中移除私人簽署資訊

在預設的情況下，簽署設定會以純文字記錄到模組的 build.gradle 檔案中。如果您與團隊或開放原始碼專案合作，可以按照下列步驟將這項機密資訊移出建構檔案。

1. 在專案的根目錄中建立名為 keystore.properties 的檔案，並提供下列資訊：

   storePassword=myStorePassword
   keyPassword=myKeyPassword
   keyAlias=myKeyAlias
   storeFile=myStoreFileLocation
   

2. 在 build.gradle 檔案中，按照下方步驟載入 keystore.properties 檔案 (必須位於 Android 區塊之前)：

   Groovy

   // Creates a variable called keystorePropertiesFile, and initializes it to the
   // keystore.properties file.
   def keystorePropertiesFile = rootProject.file("keystore.properties")
   
   // Initializes a new Properties() object called keystoreProperties.
   def keystoreProperties = new Properties()
   
   // Loads the keystore.properties file into the keystoreProperties object.
   keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
   
   android {
     ...
   }
   ...
   

   Kotlin

   // Creates a variable called keystorePropertiesFile, and initializes it to the
   // keystore.properties file.
   def keystorePropertiesFile = rootProject.file("keystore.properties")
   
   // Initializes a new Properties() object called keystoreProperties.
   def keystoreProperties = new Properties()
   
   // Loads the keystore.properties file into the keystoreProperties object.
   keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
   
   android {
     ...
   }
   ...
   

3. 輸入 keystoreProperties 物件中儲存的簽署資訊：

   Groovy

   android {
     signingConfigs {
       config {
         keyAlias keystoreProperties['keyAlias']
         keyPassword keystoreProperties['keyPassword']
         storeFile file(keystoreProperties['storeFile'])
         storePassword keystoreProperties['storePassword']
       }
     }
     ...
   }
   ...
   

   Kotlin

   android {
     signingConfigs {
       config {
         keyAlias keystoreProperties['keyAlias']
         keyPassword keystoreProperties['keyPassword']
         storeFile file(keystoreProperties['storeFile'])
         storePassword keystoreProperties['storePassword']
       }
     }
     ...
   }
   ...
   

4. 按一下通知列中的「立即同步」。

如要進一步瞭解應用程式簽署，請參閱「簽署應用程式」。

簡化應用程式開發作業

下列提示可協助您輕鬆開發 Android 應用程式。

與您的應用程式程式碼共用自訂欄位和資源值

在建構時間，Gradle 會產生 BuildConfig 類別，因此應用程式程式碼可以檢查目前建構的相關資訊。您也可以使用 buildConfigField() 方法，從 Gradle 建構設定檔的 BuildConfig 類別新增自訂欄位，並在應用程式的執行階段程式碼中存取這些值。同樣地，您可以使用 resValue() 新增應用程式資源值。

Groovy

android {
  ...
  buildTypes {
    release {
      // These values are defined only for the release build, which
      // is typically used for full builds and continuous builds.
      buildConfigField("String", "BUILD_TIME", "\"${minutesSinceEpoch}\"")
      resValue("string", "build_time", "${minutesSinceEpoch}")
      ...
    }
    debug {
      // Use static values for incremental builds to ensure that
      // resource files and BuildConfig aren't rebuilt with each run.
      // If these rebuild dynamically, they can interfere with
      // Apply Changes as well as Gradle UP-TO-DATE checks.
      buildConfigField("String", "BUILD_TIME", "\"0\"")
      resValue("string", "build_time", "0")
    }
  }
}
...

Kotlin

android {
  ...
  buildTypes {
    release {
      // These values are defined only for the release build, which
      // is typically used for full builds and continuous builds.
      buildConfigField("String", "BUILD_TIME", "\"${minutesSinceEpoch}\"")
      resValue("string", "build_time", "${minutesSinceEpoch}")
      ...
    }
    debug {
      // Use static values for incremental builds to ensure that
      // resource files and BuildConfig aren't rebuilt with each run.
      // If these rebuild dynamically, they can interfere with
      // Apply Changes as well as Gradle UP-TO-DATE checks.
      buildConfigField("String", "BUILD_TIME", "\"0\"")
      resValue("string", "build_time", "0")
    }
  }
}
...

在應用程式程式碼中，您可以透過下列方式存取屬性：

Kotlin

...
Log.i(TAG, BuildConfig.BUILD_TIME)
Log.i(TAG, getString(R.string.build_time))

Java

...
Log.i(TAG, BuildConfig.BUILD_TIME);
Log.i(TAG, getString(R.string.build_time));

與資訊清單共用資源

在某些情況下，您可能需要在資訊清單和程式碼中宣告相同的屬性 (例如宣告 FileProvider 的授權單位)。與其在多個位置更新相同的屬性以反映變更，不如在模組的 build.gradle 檔案中定義單一屬性，讓資訊清單和程式碼都能使用這項屬性，如以下範例所示。詳情請參閱「將建構變數插入資訊清單」。

Groovy

android {
  // For settings specific to a product flavor, configure these properties
  // for each flavor in the productFlavors block.
  defaultConfig {
    // Creates a property for the FileProvider authority.
    def filesAuthorityValue = applicationId + ".files"
    // Creates a placeholder property to use in the manifest.
    manifestPlaceholders =
      [filesAuthority: filesAuthorityValue]
      // Adds a new field for the authority to the BuildConfig class.
      buildConfigField("String",
                       "FILES_AUTHORITY",
                       "\"${filesAuthorityValue}\"")
  }
  ...
}
...

Kotlin

android {
  // For settings specific to a product flavor, configure these properties
  // for each flavor in the productFlavors block.
  defaultConfig {
    // Creates a property for the FileProvider authority.
    val filesAuthorityValue = applicationId + ".files"
    // Creates a placeholder property to use in the manifest.
    manifestPlaceholders["filesAuthority"] = filesAuthorityValue
      // Adds a new field for the authority to the BuildConfig class.
      buildConfigField("String",
                       "FILES_AUTHORITY",
                       "\"${filesAuthorityValue}\"")
  }
  ...
}
...

在資訊清單中按照下列說明存取預留位置：

<manifest>
  ...
  <application>
    ...
    <provider
      android:name="android.support.v4.content.FileProvider"
      android:authorities="${filesAuthority}"
      android:exported="false"
      android:grantUriPermissions="true">
      ...
    </provider>
  </application>
</manifest>

存取應用程式程式碼中的 FILES_AUTHORITY 欄位看起來會像這樣：

Kotlin

...
val contentUri: Uri = FileProvider.getUriForFile(context, BuildConfig.FILES_AUTHORITY, myFile)

Java

...
Uri contentUri = FileProvider.getUriForFile(getContext(),
  BuildConfig.FILES_AUTHORITY,
  myFile);