java.lang.IollegalArgumentException:在空Android上找不到存储设备

Question

我在内存访问方面遇到问题。最奇怪的是，这个错误甚至在互联网上都找不到。这个错误发生在安卓11的设备上。

与问题相关的方法：

void  initSaveDataFolder(){
if(SecurityPreferences.getAutoChosseFolder())
for (File file : App.get().getExternalCacheDirs()) {
try {
if (Environment.isExternalStorageRemovable(file)) {
//System.out.println("getExternalCacheDirs is "+new Gson().toJson(file));
StatFs stat = new StatFs(file.getAbsolutePath());
long bytesAvailableInSdCard = (long)stat.getBlockSize() *(long)stat.getAvailableBlocks();
StatFs stat2 = new StatFs( App.get().getExternalCacheDir().getAbsolutePath());
long bytesAvailableInInternalMemory = (long)stat2.getBlockSize() *(long)stat2.getAvailableBlocks();
if(bytesAvailableInSdCard>bytesAvailableInInternalMemory)   SecurityPreferences.setIsSaveDataOnUsb(true);
else  SecurityPreferences.setIsSaveDataOnUsb(false);
System.out.println("memoryes is "+ bytesAvailableInSdCard+" "+bytesAvailableInInternalMemory);
SecurityPreferences.saveAutoChosseFolder(true);
break;
}
}catch (NullPointerException e){
SecurityPreferences.setIsSaveDataOnUsb(false); break;
}
}
}

与存储访问相关的权限：

<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE"
tools:ignore="ScopedStorage" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_INTERNAL_STORAGE" />

错误堆栈跟踪：

Fatal Exception: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.estvisx.ma/com.estvisx.ma.ui.splash.SplashActivity}: java.lang.IllegalArgumentException: Failed to find storage device at null
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3431)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3595)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7664)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Caused by java.lang.IllegalArgumentException: Failed to find storage device at null
at android.os.Environment.isExternalStorageRemovable(Environment.java:1202)
at com.estvisx.ma.ui.splash.SplashActivity.initSaveDataFolder(SplashActivity.java:297)
at com.estvisx.ma.ui.splash.SplashActivity.onCreate(SplashActivity.java:83)
at android.app.Activity.performCreate(Activity.java:7994)
at android.app.Activity.performCreate(Activity.java:7978)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1534)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3404)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3595)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7664)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

我试着找了一整天这个问题，但什么也没找到。我只是不知道。

Answer 1

getExternalCacheDirs()的文档明确指出，它返回一个包含以下内容的File数组：

File[]-应用程序特定目录的绝对路径。一些如果共享存储当前不存在，则单个路径可能为空可获得的返回的第一个路径与getExternalCacheDir((。

因此，您需要检查返回数组中的每个条目是否存在null。在您的情况下，您在数组中得到一个null条目，该条目导致了此异常。