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」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
)。如要進一步縮減程式碼,請嘗試位於相同位置的 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。
- 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
- 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 { ... } ...
- 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'] } } ... } ...
- 按一下通知列中的「Sync Now」。
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 (例如為 FileProvider
宣告授權時)。與其更新多個位置中的相同屬性來反映某項變更,您可以在模組的 build.gradle
檔案中定義單一屬性,讓資訊清單和程式碼同時提供該屬性,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);