title: enable button from another activity
body: <p>I want to enable my btn_test which i set in false. here is my code in mainactivity.java</p>
  
  <pre><code>  btn_test= (Button) findViewById(R.id.btn_test);
       btn_test.setEnabled(false);
  </code></pre>
  
  <p>then in another class, Changactivity.java
  i need to set a pattern first</p>
  
  <pre><code>if(password.equals(PATTERN_KEY)){
                  Toast.makeText(getApplicationContext(), "Pattern created successfully!", Toast.LENGTH_SHORT).show();
                  Intent intent = new Intent(ChangeActivity.this, MainActivity.class);
  
  
                  editor.putString("Pattern", password);
                  editor.commit();
  
                  startActivity(intent);
                  finish();
  </code></pre>
  
  <p>how I can go back to Mainactivity.java and set the btn_test into true??</p>