我想在模拟器的目录中保存/创建一个文件,但是我做不到,而且我不明白我的代码有什么问题。因此,每次我尝试运行代码时,都会说android无法在此类目录中创建文件。 有人可以向我解释我是如何做到的。这是我的应用程序的代码:
公共类MainActivity扩展了AppCompatActivity {
private int STORAGE_PERMISSION_CODE = 1;
private File csvFile;
SimpleDateFormat TIME;
private static final String CSV_DIRECTORY = "NameOfTheDirectory";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if((ContextCompat.checkSelfPermission(MainActivity.this,
Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED)){
Toast.makeText(MainActivity.this, "You have already granted this permission",
Toast.LENGTH_SHORT).show();
}else {
requestStoragePermission();
}
}
public void makeFile(View view) {
File csvDirectory = new File(
Environment.getExternalStorageDirectory().getAbsolutePath() +
File.separator + CSV_DIRECTORY);
if(!csvDirectory.exists()) {
try{
csvDirectory.mkdir();
Log.d("StateMakeFile","Directory created");
} catch(Exception e) {
e.printStackTrace();
Log.d("StateMakeFile","Directory not created");
}
}
File categoryDirectory = new File(
Environment.getExternalStorageDirectory().getAbsolutePath() +
File.separator + CSV_DIRECTORY + File.separator + "NameOfTheCategory");
if(!categoryDirectory.exists()){
try{
categoryDirectory.mkdir();
Log.d("StateMakeFile","CategoryDirectory created");
}catch (Exception e){
e.printStackTrace();
Log.d("StateMakeFile","CategoryDirectory not created");
}
}
TIME = new SimpleDateFormat("yyyyMMdd-hh:mm:ss:SSS", Locale.getDefault());
String uniqueFileName = TIME.format(new Date());
csvFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath() +
File.separator + CSV_DIRECTORY + File.separator + "NameOfTheCategory" +
File.separator + uniqueFileName + ".csv");
if(!csvFile.exists()){
try{
csvFile.createNewFile();
Log.d("StateMakeFile","File created");
}catch (IOException e){
e.printStackTrace();
Log.d("StateMakeFile","File not created");
}
if(csvFile.exists()) {
try{
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(csvFile, true)));
out.write("Something" + "\n");
out.flush();
out.close();
Log.d("StateMakeFile","File was writed with success");
}catch (IOException e){
e.printStackTrace();
Log.d("StateMakeFile","File wasnt writed with success");
}
}
}
}
private void requestStoragePermission() {
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.READ_EXTERNAL_STORAGE)) {
new AlertDialog.Builder(this)
.setTitle("Permission needed")
.setMessage("This permission is needed to save and load files into ssd")
.setPositiveButton("ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
ActivityCompat.requestPermissions(MainActivity.this,
new String[] {Manifest.permission.READ_EXTERNAL_STORAGE}, STORAGE_PERMISSION_CODE);
}
})
.setNegativeButton("cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
})
.create().show();
} else {
ActivityCompat.requestPermissions(this,
new String[] {Manifest.permission.READ_EXTERNAL_STORAGE}, STORAGE_PERMISSION_CODE);
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if (requestCode == STORAGE_PERMISSION_CODE) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "Permission GRANTED", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Permission DENIED", Toast.LENGTH_SHORT).show();
}
}
}
}
答案 0 :(得分:0)
我不知道它是否在您的清单中,但您正在与之合作
READ_EXTERNAL_STORAGE
在获得许可的情况下尝试
WRITE_EXTERNAL_STORAGE
希望这对您有帮助