title: EditText value of custom AlertDialog to Textview
body: <p>I found some similar questions here, but all of their were either really confusing for such a newbie like me or didn't help to solve my problem:
  I have a TextView tv. By click on it I want to display a custom AlertDialog with EditText + Cancel- and Update-Buttons. By click on Update-Button of my Dialog I want to replace the text of the same TextView (tv) with the value of EditText from Dialog. Here is one of my attepmts:</p>
  
  <pre><code>...
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
      final TextView tv̶̶C̶̶l̶̶i̶̶c̶̶k̶̶e̶̶d̶ = (TextView) findViewById(R.id.tv_id);
      tv.setText("Initial value");
  
      tv.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              UpdateDialogFragment updDiag = new UpdateDialogFragment();
              updDiag.show(getFragmentManager(), "dialog");
              tv.setText(updDiag.value); // I try to get the value of EditText like this, but it doesn't work
          }
          });
  }
  
  public class UpdateDialogFragment extends DialogFragment {
      String value; // I try to get the value of EditText like this, but it doesn't work
      @Override
      public Dialog onCreateDialog(Bundle savedInstanceState) {
  
          AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
          LayoutInflater inflater = getActivity().getLayoutInflater();
  
          builder.setView(inflater.inflate(R.layout.edit_tv, null))
                  .setPositiveButton("Update", new DialogInterface.OnClickListener() {
                      @Override
                      public void onClick(DialogInterface dialog, int id) {
                          EditText et = (EditText) UpdateDialogFragment.this.getDialog().findViewById(R.id.et_tv);
                          value = et.getText().toString();  // I try to get the value of EditText like this, but it doesn't work
                      }
                  })
                  .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                      public void onClick(DialogInterface dialog, int id) {
                          UpdateDialogFragment.this.getDialog().cancel();
                      }
                  });
          return builder.create();
      }
  }
  </code></pre>
  
  <p>And my edit_tv.xml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical" android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;EditText
          android:id="@+id/et_tv"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:ems="10"
          android:layout_marginTop="40dp"
          android:hint="Enter text ..."
          android:layout_gravity="center_horizontal"&gt;
  
          &lt;requestFocus /&gt;
      &lt;/EditText&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>activity_main.xml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:paddingBottom="@dimen/activity_vertical_margin"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      tools:context="com.yev.tabletasting.MainActivity"&gt;
  
      &lt;TextView
          android:id="@+id/tv_id"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content" /&gt;    
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>In my case the Text of tv will be setted to "" (probably null) after click on "Update".
  I would be thankful for every advice, thanking you in anticipation!</p>