Show Error on the tip of the Edit Text Android

String a = text.getText().toString();");

String s= String from edittext;
boolean p=s.contains(" ");
if(p)
    //call function for error
else
    //safe to proceed

<shape xmlns:android="http://schemas.android.com/apk/res/android"
  android:shape="rectangle">
  <solid android:color="@android:color/darker_gray"/>
  <stroke
      android:width="1px"
      android:color="@android:color/darker_gray"/>
</shape>

<shape xmlns:android="http://schemas.android.com/apk/res/android"
  android:shape="rectangle">
  <solid android:color="@android:color/white"/>
  <stroke
      android:width="1px"
      android:color="@android:color/darker_gray"/>
</shape>

<LinearLayout
     android:id="@+id/ll"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:orientation="horizontal"
    android:weightSum="1" >

    <EditText
        android:id="@+id/et"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight=".8"
        android:text="aaa"
        android:background="@drawable/edit_border" />

    <Button
        android:id="@+id/bt"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight=".2"
        android:text="Send" 
        android:background="@drawable/button_border" />
</LinearLayout>

editText.setOnClickListener(new View.OnClickListener() {

                    @Override
                    public void onClick(View arg0) {
                        // do things you want
                    }
                });