Intercept back button from soft keyboard（从软键盘拦截后退按钮）

onKeyDown() and onBackPressed() doesn't work for this case. You have to use onKeyPreIme.

Initially, you have to create custom edit text that extends EditText. And then you have to implement onKeyPreIme method which controls KeyEvent.KEYCODE_BACK. After this, one back press enough for solve your problem. This solution works for me perfectly.

CustomEditText.java

public class CustomEditText extends EditText {

    Context context;

    public CustomEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
    }

    @Override
    public boolean onKeyPreIme(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // User has pressed Back key. So hide the keyboard
            InputMethodManager mgr = (InputMethodManager)         
                context.getSystemService(Context.INPUT_METHOD_SERVICE);
            mgr.hideSoftInputFromWindow(this.getWindowToken(), 0);
            // TODO: Hide your view as you do it in your activity
        }
        return false;
}

In your XML

<com.YOURAPP.CustomEditText
     android:id="@+id/CEditText"
     android:layout_height="wrap_content"
     android:layout_width="match_parent"/>

In your Activity

public class MainActivity extends Activity {
   private CustomEditText editText;

   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      editText = (CustomEditText) findViewById(R.id.CEditText);
   }
}

解决方案出版：
http://stackoverflow.com/questions/3940127/intercept-back-button-from-soft-keyboard