Android警报对话框不显示EDITTEXT值

Question

我在代码的一部分中被击中，其中显示了一个警报框，要求用户输入数据集的名称。同名文件将在内部存储中创建。警报对话框正常工作，但是SD卡中创建的文件始终为" null.txt"。经过数小时的搜索，我尝试了所有解决方案，例如为警报框创建自定义布局，将TextWatcher添加到edittext等，但没有帮助。当我将数据集的名称分配给变量" SET"时，该文件将成功创建。因此，alertdialog存在问题。我正在使用Android Studio 2.3.1。请帮助。

我也在发布代码。

else if (map2.contains("1") || map2.contains("4")) {
    final EditText edittext = new EditText(Scan.this);
    AlertDialog.Builder alert1 = new AlertDialog.Builder(Scan.this);
    alert1.setMessage("Name of the dataset");
    alert1.setTitle("Enter Your Title");
    alert1.setView(edittext);
    alert1.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            String set = edittext.getText().toString();
            Set = set;
        }
    });
    alert1.setNegativeButton("Cancel", new DialogInterface.OnClickListener(){
        public void onClick(DialogInterface dialog, int whichButton) {
        }
    });
    alert1.show();
}
myFile = new File(Environment.getExternalStorageDirectory(),Set+".txt");
if (!myFile.exists()) {
    try {
        myFile.createNewFile();
        FileOutputStream fOut = new FileOutputStream(myFile);
        OutputStreamWriter osw = new OutputStreamWriter(fOut);
        osw.write(message1);
        osw.flush();
        osw.close();
        fOut.close();
    }
    catch (Exception e) {
        e.printStackTrace();
    }
   finally {
   }
}

Answer 1

您在对话框中设置标题之前创建文件。尝试以下操作：

else if (map2.contains("1") || map2.contains("4")) {
    final EditText edittext = new EditText(Scan.this);
    AlertDialog.Builder alert1 = new AlertDialog.Builder(Scan.this);
    alert1.setMessage("Name of the dataset");
    alert1.setTitle("Enter Your Title");
    alert1.setView(edittext);
    alert1.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            String set = edittext.getText().toString();
            createFile(set);
        }
    });
    alert1.setNegativeButton("Cancel", new DialogInterface.OnClickListener(){
        public void onClick(DialogInterface dialog, int whichButton) {
        }
    });
    alert1.show();
}
}
private void createFile(String set){
   myFile = new 
 File(Environment.getExternalStorageDirectory(),set+".txt");
   if (!myFile.exists()) {
       try {
           myFile.createNewFile();
           FileOutputStream fOut = new FileOutputStream(myFile);
           OutputStreamWriter osw = new OutputStreamWriter(fOut);
           osw.write(message1);
           osw.flush();
           osw.close();
           fOut.close();
       }
       catch (Exception e) {
           e.printStackTrace();
       }
       finally {
       }
   }

}

Answer 2

您是否在清单中给出了权限：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

请检查以创建.txt文件。

   String editString = mEditText.getText().toString();
   filename = fileName_mEditText.getText().toString();
   if (filename.trim().equalsIgnoreCase("")) {
       fileName_mEditText.setError("Enter File Name!");
   }else if (editString.trim().equalsIgnoreCase("")) {
       mEditText.setError("Enter Text!");
   } else {
       try {
            FileOperations fop = new FileOperations();
            fop.write(filename, editString);
            if (fop.write(filename, editString)) {
                 Toast.makeText(getApplicationContext(), filename + ".txt created", Toast.LENGTH_SHORT).show();
            } else {
                 Toast.makeText(getApplicationContext(), "I/O error", Toast.LENGTH_SHORT).show();
            }
            } catch (Exception e) {
                    e.printStackTrace();
            }
       }
  }

Answer 3

尝试以下代码：

将包含Edittext的自定义布局夸大，然后使用它：

 LayoutInflater inflater = LayoutInflater.from(Scan.this);            
final View view = inflater.inflate(R.layout.custom_layout, null);
AlertDialog.Builder alert = new AlertDialog.Builder(Scan.this); 
alert.setTitle("Tilte"); 
alert.setMessage("Name of the dataset"); 
alert.setView(view); 
final EditText et1 = (EditText) view.findViewById(R.id.editText1);
alert.setPositiveButton("ok", new DialogInterface.OnClickListener() { 
   public void onClick(DialogInterface dialog, int whichButton) 
   { 
          String s1=et1.getText().toString();
          //do operations using s1...
          myFile = new File(Environment.getExternalStorageDirectory(),s1+".txt");
            if (!myFile.exists()) {
                try {
                    myFile.createNewFile();
                    FileOutputStream fOut = new FileOutputStream(myFile);
                    OutputStreamWriter osw = new OutputStreamWriter(fOut);
                    osw.write(message1);
                    osw.flush();
                    osw.close();
                    fOut.close();
                }
                catch (Exception e) {
                    e.printStackTrace();
                }
               finally {
               }
        } 
}); 
alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
   public void onClick(DialogInterface dialog, int whichButton) { 
            dialog.cancel(); 
   } 
}); 
alert.show(); 

来自@deepti maduskar

最后，我可以解决这个问题。问题在于全局有效集的定义。我只需要声明它而不是将其定义为final。