我正在尝试从我之前写过的设备中读取数据。但是当我尝试读取它时，我收到了IllegalArgumentException。实际上我试图写入外部SD卡但它已存储在设备存储中。我努力但无法找到将数据写入外部SD卡的解决方案。但真正的问题是我无法从文件中读取。虽然我已经在stackoverflow帖子中看到了很多这样的代码，但是之前将openFileInput分配给FileInputStream给了我一个NullPointerException。下面是代码。请帮我在代码中找到错误。
代码：
public String getExternalSdCardPath()
{
String path=null;
File sdcardfile=null;
List<String> sdpossiblepath= Arrays.asList("external_sd","ext_sd","external","extSdCard","sdcard2");
for (String sdpath:sdpossiblepath)
{
File file=new File("mnt/",sdpath);
if (file.isDirectory()&&file.canWrite())
{
path=file.getAbsolutePath();
String timestamp=new SimpleDateFormat("ddMMyyyy_HHmmss").format(new Date());
File testWritable=new File(path,"test_"+timestamp);
if (testWritable.mkdirs())
{
testWritable.delete();
}
else {
path=null;
}
}
}
if (path!=null)
{
sdcardfile=new File(path);
}
else {
sdcardfile=new File(Environment.getExternalStorageDirectory().getAbsolutePath());
}
return sdcardfile.getAbsolutePath();
}
public String readFromStorage1()
{
File dir=new File(getExternalSdCardPath()+"/tut");
if (dir.exists()){
File file=new File(getExternalSdCardPath()+"/tut" + "/savedfile.txt");
if (file.exists())
{
try {
fileInputStream=getApplicationContext().openFileInput(getExternalSdCardPath()+"/tut/"+"savedfile.txt");
isr=new InputStreamReader(fileInputStream);
bufferedReader=new BufferedReader(isr);
stringBuilder=new StringBuilder();
while (bufferedReader.readLine()!=null)
{
stringBuilder.append(bufferedReader.readLine());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally {
try {
if (fileInputStream!=null) {
fileInputStream.close();
}
if (isr!=null) {
isr.close();
}
if (bufferedReader!=null)
{bufferedReader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
else {
return "Null";
}}else {
return "Null";
}
if (stringBuilder!=null&&stringBuilder.length()>0)
{
return stringBuilder.toString();
}
else {
return "Null";
}
}
例外：
java.lang.IllegalArgumentException: File /storage/emulated/0/tut/savedfile.txt contains a path separator
at android.app.ContextImpl.makeFilename(ContextImpl.java:2663)
at android.app.ContextImpl.openFileInput(ContextImpl.java:1144)
at android.content.ContextWrapper.openFileInput(ContextWrapper.java:183)
at com.globemaster.internalstorage.MainActivity.readFromStorage1(MainActivity.java:190)
at com.globemaster.internalstorage.MainActivity$2.onClick(MainActivity.java:54)
at android.view.View.performClick(View.java:5076)
at android.view.View$PerformClick.run(View.java:20279)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5930)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)