Putting custom method to custom component

Question

I have custom component extends LinearLayout. I need create attribute for putting custom method for this component. And I need call it inside component.

Like as Button.

<Button android:onClick="customMethod"/>

How to fix it?

Answer 1

Looking at the source code of the View class in the Android java file you can find the following

            case R.styleable.View_onClick:
                if (context.isRestricted()) {
                    throw new IllegalStateException("The android:onClick attribute cannot "
                            + "be used within a restricted context");
                }

                final String handlerName = a.getString(attr);
                if (handlerName != null) {
                    setOnClickListener(new OnClickListener() {
                        private Method mHandler;

                        public void onClick(View v) {
                            if (mHandler == null) {
                                try {
                                    mHandler = getContext().getClass().getMethod(handlerName,
                                            View.class);
                                } catch (NoSuchMethodException e) {
                                    int id = getId();
                                    String idText = id == NO_ID ? "" : " with id '"
                                            + getContext().getResources().getResourceEntryName(
                                                id) + "'";
                                    throw new IllegalStateException("Could not find a method " +
                                            handlerName + "(View) in the activity "
                                            + getContext().getClass() + " for onClick handler"
                                            + " on view " + View.this.getClass() + idText, e);
                                }
                            }

                            try {
                                mHandler.invoke(getContext(), View.this);
                            } catch (IllegalAccessException e) {
                                throw new IllegalStateException("Could not execute non "
                                        + "public method of the activity", e);
                            } catch (InvocationTargetException e) {
                                throw new IllegalStateException("Could not execute "
                                        + "method of the activity", e);
                            }
                        }
                    });
                }
                break;

The getMethod method should be what you are looking for.

Answer 2

Have you seen this post:

Android - Writing a custom (compound) component

Could be the answer you are looking for.