title: cannot find symbol setError() in validation of username and password
body: <p>When i was trying to validate my username and password I am getting an error saying setError is not found can you please help me out in finding my mistake.I performed this in androidstudio1.2.2</p>
  <h1>login.java</h1>
  <pre><code>package com.example.poornima.bookmyticket;
  
  import com.example.poornima.bookmyticket.util.SystemUiHider;
  
  import android.annotation.TargetApi;
  import android.app.Activity;
  import android.content.Intent;
  import android.os.Build;
  import android.os.Bundle;
  import android.os.Handler;
  import android.view.MotionEvent;
  import android.view.View;
  import android.widget.Button;
  import android.widget.EditText;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import android.view.Menu;
  import android.widget.TextView;
  import android.widget.Toast;
  
  
  /**
   * An example full-screen activity that shows and hides the system UI (i.e.
   * status bar and navigation/system bar) with user interaction.
   *
   * @see SystemUiHider
   */
  public class login extends Activity implements View.OnClickListener {
      private Button bLogin, bRegister;
     private  EditText eusername, epassword;
  
  
      /**
       * Whether or not the system UI should be auto-hidden after
       * {@link #AUTO_HIDE_DELAY_MILLIS} milliseconds.
       */
      private static final boolean AUTO_HIDE = true;
  
      /**
       * If {@link #AUTO_HIDE} is set, the number of milliseconds to wait after
       * user interaction before hiding the system UI.
       */
      private static final int AUTO_HIDE_DELAY_MILLIS = 3000;
  
      /**
       * If set, will toggle the system UI visibility upon interaction. Otherwise,
       * will show the system UI visibility upon interaction.
       */
      private static final boolean TOGGLE_ON_CLICK = true;
  
      /**
       * The flags to pass to {@link SystemUiHider#getInstance}.
       */
      private static final int HIDER_FLAGS = SystemUiHider.FLAG_HIDE_NAVIGATION;
  
      /**
       * The instance of the {@link SystemUiHider} for this activity.
       */
      private SystemUiHider mSystemUiHider;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
  
          setContentView(R.layout.activity_login);
  
          final View controlsView = findViewById(R.id.fullscreen_content_controls);
          final View contentView = findViewById(R.id.fullscreen_content);
  
          bLogin = (Button) findViewById(R.id.bLogin);
          bRegister = (Button) findViewById(R.id.bRegister);
          eusername = (EditText) findViewById(R.id.eusername);
          epassword = (EditText) findViewById(R.id.epassword);
          bLogin.setOnClickListener(this);
          bRegister.setOnClickListener(this);
          // Set up an instance of SystemUiHider to control the system UI for
          // this activity.
          mSystemUiHider = SystemUiHider.getInstance(this, contentView, HIDER_FLAGS);
          mSystemUiHider.setup();
          mSystemUiHider
                  .setOnVisibilityChangeListener(new SystemUiHider.OnVisibilityChangeListener() {
                      // Cached values.
                      int mControlsHeight;
                      int mShortAnimTime;
  
                      @Override
                      @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
                      public void onVisibilityChange(boolean visible) {
                          if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.HONEYCOMB_MR2) {
                              // If the ViewPropertyAnimator API is available
                              // (Honeycomb MR2 and later), use it to animate the
                              // in-layout UI controls at the bottom of the
                              // screen.
                              if (mControlsHeight == 0) {
                                  mControlsHeight = controlsView.getHeight();
                              }
                              if (mShortAnimTime == 0) {
                                  mShortAnimTime = getResources().getInteger(
                                          android.R.integer.config_shortAnimTime);
                              }
                              controlsView.animate()
                                      .translationY(visible ? 0 : mControlsHeight)
                                      .setDuration(mShortAnimTime);
                          } else {
                              // If the ViewPropertyAnimator APIs aren't
                              // available, simply show or hide the in-layout UI
                              // controls.
                              controlsView.setVisibility(visible ? View.VISIBLE : View.GONE);
                          }
  
                          if (visible &amp;&amp; AUTO_HIDE) {
                              // Schedule a hide().
                              delayedHide(AUTO_HIDE_DELAY_MILLIS);
                          }
                      }
                  });
  
          // Set up the user interaction to manually show or hide the system UI.
          contentView.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
                  if (TOGGLE_ON_CLICK) {
                      mSystemUiHider.toggle();
                  } else {
                      mSystemUiHider.show();
                  }
              }
          });
  
          // Upon interacting with UI controls, delay any scheduled hide()
          // operations to prevent the jarring behavior of controls going away
          // while interacting with the UI.
  
      }
  
  
      @Override
      public void onClick(View arg0) {
          final String username = eusername.getText().toString();
          if (!isValidUsername(username)) {
              username.setError(&quot;Invalid Email&quot;);
          }
  
          final String password = epassword.getText().toString();
          if (!isValidPassword(password)) {
              password.setError(&quot;Invalid Password&quot;);
  
          }
  
      }
  
  
      @Override
      protected void onPostCreate(Bundle savedInstanceState) {
          super.onPostCreate(savedInstanceState);
  
          // Trigger the initial hide() shortly after the activity has been
          // created, to briefly hint to the user that UI controls
          // are available.
          delayedHide(100);
      }
  
  
      /**
       * Touch listener to use for in-layout UI controls to delay hiding the
       * system UI. This is to prevent the jarring behavior of controls going away
       * while interacting with activity UI.
       */
      View.OnTouchListener mDelayHideTouchListener = new View.OnTouchListener() {
          @Override
          public boolean onTouch(View view, MotionEvent motionEvent) {
              if (AUTO_HIDE) {
                  delayedHide(AUTO_HIDE_DELAY_MILLIS);
              }
              return false;
          }
      };
  
      Handler mHideHandler = new Handler();
      Runnable mHideRunnable = new Runnable() {
          @Override
          public void run() {
              mSystemUiHider.hide();
          }
      };
  
      /**
       * Schedules a call to hide() in [delay] milliseconds, canceling any
       * previously scheduled calls.
       */
      private void delayedHide(int delayMillis) {
          mHideHandler.removeCallbacks(mHideRunnable);
          mHideHandler.postDelayed(mHideRunnable, delayMillis);
      }
  
      private boolean isValidUsername(String username) {
          if (username != null &amp;&amp; username.length() &gt; 4) {
              return true;
          }
          return false;
      }
  
      private boolean isValidPassword(String pass) {
          if (pass != null &amp;&amp; pass.length() &gt; 6) {
              return true;
          }
          return false;
      }
  }
  </code></pre>
  <pre class="lang-html prettyprint-override"><code>&lt;RelativeLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
      xmlns:tools=&quot;http://schemas.android.com/tools&quot; android:layout_width=&quot;match_parent&quot;
      android:layout_height=&quot;match_parent&quot; android:background=&quot;@drawable/train1&quot;
      tools:context=&quot;gss.bookmyticket.LOGIN&quot;&gt;
  
  &lt;LinearLayout
      android:id=&quot;@+id/fullscreen_content_controls&quot;
      style=&quot;?metaButtonBarStyle&quot;
      android:layout_width=&quot;match_parent&quot;
      android:layout_height=&quot;wrap_content&quot;
      android:layout_gravity=&quot;bottom|center_horizontal&quot;
      android:orientation=&quot;horizontal&quot;
      tools:ignore=&quot;UselessParent&quot; &gt;
  &lt;/LinearLayout&gt;
  &lt;TextView
  android:id=&quot;@+id/fullscreen_content&quot;
  android:layout_width=&quot;match_parent&quot;
  android:layout_height=&quot;match_parent&quot;
  android:gravity=&quot;center&quot;
  android:keepScreenOn=&quot;true&quot;
  android:text=&quot; &quot;
  android:textStyle=&quot;bold&quot;
  android:layout_below=&quot;@+id/fullscreen_content_controls&quot;
  android:layout_alignParentStart=&quot;true&quot; /&gt;
  
  
  &lt;ImageButton
  android:layout_width=&quot;wrap_content&quot;
  android:layout_height=&quot;wrap_content&quot;
  android:id=&quot;@+id/imageButton&quot;
  android:src=&quot;@drawable/image1&quot;
  android:background=&quot;@android:color/transparent&quot;
  android:layout_below=&quot;@+id/fullscreen_content_controls&quot;
  android:layout_centerHorizontal=&quot;true&quot; /&gt;
  
  &lt;EditText
  android:layout_width=&quot;300dp&quot;
  android:layout_height=&quot;50dp&quot;
  android:id=&quot;@+id/eusername&quot;
  android:background=&quot;@drawable/s1&quot;
  android:textColor=&quot;#78909C&quot;
  android:hint=&quot;USERNAME&quot;
  android:gravity=&quot;center&quot;
  android:layout_marginTop=&quot;46dp&quot;
  android:layout_below=&quot;@+id/imageButton&quot;
  android:layout_centerHorizontal=&quot;true&quot; /&gt;
  
  &lt;EditText
  android:layout_width=&quot;300dp&quot;
  android:layout_height=&quot;50dp&quot;
  android:inputType=&quot;textPassword&quot;
  android:gravity=&quot;center&quot;
  android:background=&quot;@drawable/s1&quot;
  android:ems=&quot;10&quot;
  android:id=&quot;@+id/epassword&quot;
  android:hint=&quot;PASSWORD&quot;
  android:textColor=&quot;#78909C&quot;
  android:layout_marginTop=&quot;60dp&quot;
  android:layout_below=&quot;@+id/eUSERNAME1&quot;
  android:layout_alignEnd=&quot;@+id/eUSERNAME1&quot;
  android:layout_alignStart=&quot;@+id/eUSERNAME1&quot; /&gt;
  
  &lt;Button
  android:layout_width=&quot;120dp&quot;
  android:background=&quot;@drawable/s2&quot;
  android:layout_height=&quot;wrap_content&quot;
  android:text=&quot;SIGN IN&quot;
  android:id=&quot;@+id/bLogin&quot;
  android:layout_alignTop=&quot;@+id/bRegister&quot;
  android:layout_alignStart=&quot;@+id/ePASSWORD1&quot; /&gt;
  
  &lt;Button
  android:layout_width=&quot;120dp&quot;
  android:layout_height=&quot;wrap_content&quot;
  android:text=&quot;SIGN UP&quot;
  android:background=&quot;@drawable/s4&quot;
  android:id=&quot;@+id/bRegister&quot;
  android:layout_alignParentBottom=&quot;true&quot;
  android:layout_alignEnd=&quot;@+id/ePASSWORD1&quot;
  android:layout_marginBottom=&quot;56dp&quot; /&gt;
  
  &lt;ImageView
  android:layout_width=&quot;25dp&quot;
  android:layout_height=&quot;25dp&quot;
  android:id=&quot;@+id/imageView&quot;
  android:src=&quot;@drawable/user&quot;
  android:layout_marginLeft=&quot;10dp&quot;
  android:paddingLeft=&quot;0dp&quot;
  android:paddingRight=&quot;0dp&quot;
  android:paddingTop=&quot;0dp&quot;
  android:paddingBottom=&quot;0dp&quot;
  android:layout_alignTop=&quot;@+id/eUSERNAME1&quot;
  android:layout_alignStart=&quot;@+id/eUSERNAME1&quot;
  android:layout_alignBottom=&quot;@+id/eUSERNAME1&quot; /&gt;
  
  &lt;ImageView
  android:layout_width=&quot;25dp&quot;
  android:layout_height=&quot;25dp&quot;
  android:src=&quot;@drawable/i3&quot;
  android:layout_marginLeft=&quot;0dp&quot;
  android:id=&quot;@+id/imageView2&quot;
  android:layout_alignTop=&quot;@+id/ePASSWORD1&quot;
  android:layout_alignBottom=&quot;@+id/ePASSWORD1&quot;
  android:layout_alignStart=&quot;@+id/imageView&quot; /&gt;
  
  
      &lt;/RelativeLayout&gt;
  </code></pre>