在 File() 上獲取目錄 android studio kotlin 的問題

Question

我無法獲取目錄，我使用的IDE是使用Kotlin語言的Android Studio，我輸入了圖像目錄的確切路徑“D:\\Fyp\\app\\src\\main\\res\\drawable\\picture.jpg” ，我已經嘗試過使用相同代碼的 IntelliJ 並且它也能工作，但是對於 android studio，它沒有工作......下面是代碼......

private fun encoder(): String {
    val bytes = File("D:\\Fyp\\app\\src\\main\\res\\drawable\\picture.jpg").readBytes()
    val base64 = Base64.getEncoder().encodeToString(bytes)
    return base64
}

這些是錯誤日志...

2019-12-16 20:26:24.415 15322-15322/com.example.fyp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.fyp, PID: 15322
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fyp/com.example.fyp.MainActivity}: java.io.FileNotFoundException: D:\Fyp\app\src\main\res\drawable\image.jpg: open failed: ENOENT (No such file or directory)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
    at android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7356)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
 Caused by: java.io.FileNotFoundException: D:\Fyp\app\src\main\res\drawable\image.jpg: open failed: ENOENT (No such file or directory)
    at libcore.io.IoBridge.open(IoBridge.java:496)
    at java.io.FileInputStream.<init>(FileInputStream.java:159)
    at kotlin.io.FilesKt__FileReadWriteKt.readBytes(FileReadWrite.kt:63)
    at com.example.fyp.MainActivity.encoder(MainActivity.kt:62)
    at com.example.fyp.MainActivity.onCreate(MainActivity.kt:57)
    at android.app.Activity.performCreate(Activity.java:7802)
    at android.app.Activity.performCreate(Activity.java:7791)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
    at android.os.Handler.dispatchMessage(Handler.java:107) 
    at android.os.Looper.loop(Looper.java:214) 
    at android.app.ActivityThread.main(ActivityThread.java:7356) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
 Caused by: android.system.ErrnoException: open failed: ENOENT (No such file or directory)
    at libcore.io.Linux.open(Native Method)
    at libcore.io.ForwardingOs.open(ForwardingOs.java:167)
    at libcore.io.BlockGuardOs.open(BlockGuardOs.java:252)
    at libcore.io.ForwardingOs.open(ForwardingOs.java:167)
    at android.app.ActivityThread$AndroidOs.open(ActivityThread.java:7255)
    at libcore.io.IoBridge.open(IoBridge.java:482)
    at java.io.FileInputStream.<init>(FileInputStream.java:159) 
    at kotlin.io.FilesKt__FileReadWriteKt.readBytes(FileReadWrite.kt:63) 
    at com.example.fyp.MainActivity.encoder(MainActivity.kt:62) 
    at com.example.fyp.MainActivity.onCreate(MainActivity.kt:57) 
    at android.app.Activity.performCreate(Activity.java:7802) 
    at android.app.Activity.performCreate(Activity.java:7791) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
    at android.os.Handler.dispatchMessage(Handler.java:107) 
    at android.os.Looper.loop(Looper.java:214) 
    at android.app.ActivityThread.main(ActivityThread.java:7356) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 

Answer 1

從 Android 應用程序使用 PC 上的文件路徑是沒有意義的。

此外，資源（項目res目錄中的任何內容）都不是已編譯應用程序中的傳統文件。 您無法將它們作為文件訪問，並且在從商店安裝應用程序后，它們甚至可能不存在於應用程序中（如果它們根據設備特征被過濾掉）。

要在您的應用程序中包含可以在運行時加載的文件，您需要將它們放在assets目錄中，而不是放在res 。 如果您還沒有assets目錄，請在src/main創建一個。 然后把你的文件放進去。 你可以這樣讀：

val bytes = context.assets.open("picture.jpg").use { it.readBytes() }

請注意包裝readBytes()調用的 use 的use 。 這是在完成讀取后關閉輸入流。 否則，您會泄漏輸入流。