Android: Backspace in WebView/BaseInputConnection

Solution 1:

Ok, finally figured this out.

In Android 4.2 (maybe in earlier versions as well) the backspace is not sent as a sendKeyEvent(..., KeyEvent.KEYCODE_DEL) by the standard soft keyboard. Instead, it is sent as deleteSurroundingText(1, 0).

So the solution in my case is to make a custom InputConnection with the following:

@Override
public boolean deleteSurroundingText(int beforeLength, int afterLength) {       
    // magic: in latest Android, deleteSurroundingText(1, 0) will be called for backspace
    if (beforeLength == 1 && afterLength == 0) {
        // backspace
        return super.sendKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL))
            && super.sendKeyEvent(new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_DEL));
    }

    return super.deleteSurroundingText(beforeLength, afterLength);
}

Note: Please let me know if I am doing something stupid here, as it is my 3rd day writing for Android.

Solution 2:

this code will be better, it work with more keyboard :D

@Override
  public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
      outAttrs.actionLabel = null;
      outAttrs.inputType = InputType.TYPE_NULL;
      final InputConnection con = new BaseInputConnection(this,false);
      InputConnectionWrapper public_con = new InputConnectionWrapper(
              super.onCreateInputConnection(outAttrs), true) {
          @Override
          public boolean deleteSurroundingText(int beforeLength, int afterLength) {
              if (beforeLength == 1 && afterLength == 0) {
                  return this.sendKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL))
                          && this.sendKeyEvent(new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_DEL));
              }
              return super.deleteSurroundingText(beforeLength, afterLength);
          }

          @Override
          public boolean sendKeyEvent(KeyEvent event) {
              if(event.getKeyCode() == KeyEvent.KEYCODE_DEL){
                  return con.sendKeyEvent(event);
              }else {
                  return super.sendKeyEvent(event);
              }
          }
      };
      try {
          return public_con ;
      }catch (Exception e){
          return super.onCreateInputConnection(outAttrs) ;
      }
  }