InputInterceptEditText.java

public class InputInterceptEditText extends EditText {
    private InputInterceptListener inputInterceptListener;

    public InputInterceptEditText(Context context) {
        super(context);
    }

    public InputInterceptEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public InputInterceptEditText(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public InputInterceptEditText(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
        InputConnection con = super.onCreateInputConnection(outAttrs);
        return new EditTextInputConnection(con, true, inputInterceptListener);
    }

    private class EditTextInputConnection extends InputConnectionWrapper {

        private InputInterceptListener inputInterceptListener;

        public EditTextInputConnection(InputConnection target, boolean mutable, InputInterceptListener listener) {
            super(target, mutable);
            this.inputInterceptListener = listener;
        }

        @Override
        public boolean commitText(CharSequence text, int newCursorPosition) {
            android.util.Log.i("LICW", String.format("commitText(%d, %d)", YcEditText.this.getSelectionStart(), newCursorPosition));
            boolean isIntercept = false;
            if (inputInterceptListener != null) {
                isIntercept = inputInterceptListener.interceptInput(getText().toString() + text, text);
            }
            return isIntercept ? false : super.commitText(text, newCursorPosition);
        }

        @Override
        public int getCursorCapsMode(int reqModes) {
            android.util.Log.i("LICW", String.format("getCursorCapsMode(%d)", reqModes));
            if (reqModes == TextUtils.CAP_MODE_SENTENCES && inputInterceptListener != null) {
                inputInterceptListener.inputComplete();
            }
            return super.getCursorCapsMode(reqModes);
        }

        @Override
        public boolean sendKeyEvent(KeyEvent event) {
            android.util.Log.i("LICW", String.format("sendKeyEvent(%s)", event));
            boolean isIntercept = false;
            if (event.getAction() == KeyEvent.ACTION_DOWN && event.getKeyCode() == KeyEvent.KEYCODE_DEL) {
                if (inputInterceptListener != null) {
                    String newStr = YcEditText.this.getText().toString();
                    if (newStr.length() > 0) {
                        isIntercept = inputInterceptListener.interceptDelete(newStr.substring(0, newStr.length() - 1));
                    }
                }
            }
            return isIntercept ? false : super.sendKeyEvent(event);
        }
    }

    public void setAcceptedChars(final String chars) {
        setKeyListener(new NumberKeyListener() {
            @Override
            protected char[] getAcceptedChars() {
                return chars.toCharArray();
            }

            @Override
            public int getInputType() {
                return EditorInfo.TYPE_CLASS_NUMBER;
            }
        });
    }

    public InputInterceptListener getInputInterceptListener() {
        return inputInterceptListener;
    }

    public void setInputInterceptListener(InputInterceptListener inputInterceptListener) {
        this.inputInterceptListener = inputInterceptListener;
    }

    public interface InputInterceptListener {
        boolean interceptInput(String newStr, CharSequence text);

        boolean interceptDelete(String newStr);

        void inputComplete();
    }
}