setEnabled() vs setClickable(), what is the differ

问题:

Until now, when I wanted to stop the user from pressing the button, I would set the button.setClickable(false); and usually change the text to some kind of grey colour (to let the user know that the button is disabled). Today I stumbled upon the setEnabled() property.

So I went to the documentation to see the method's explanation below:

setEnabled(boolean enabled)
   Set the enabled state of this view.

What does this even mean? What is the difference between enable state/clickable state and disabled state/not clickable state? Could someone please explain what is the difference between doing what I was doing previously, using the clickable property and using the setEnabled() property? What should be used when? I searched StackOverflow but could not find anything related. Thanks in advance.

回答1:

What the hell is that mean?

Quoting the Wikipedia page for "GUI widget":

In the context of an application, a widget may be enabled or disabled at a given point in time. An enabled widget has the capacity to respond to events, such as keystrokes or mouse actions. A widget that cannot respond to such events is considered disabled. The appearance of disabled widget is typically different from an enabled widget; the disabled widget may be drawn in a lighter color, or may be visually obscured in some way. See the image to the right for an example.

This concept has been around for a couple of decades and can be found in most GUI frameworks.

what is the difference between enable state/clickable state and disabled state/ not clickable state?

In Android, a widget that is not clickable will not respond to click events. A disabled widget not only is not clickable, but it also visually indicates that it is disabled.

what do you mean by: "..since it makes the Button visually "disabled"? how does it changes it visually?

What makes a Button look and respond like a Button is its background, which is a StateListDrawable. There is a specific image used for the disabled state.

回答2:

So basically an enabled false doesn't respond to any response and an clickable false still response when set at runtime and trust me I just tried it.

回答3:

As Dilip said, setClickable does not works if set at runtime. Here is a trick to make it working:

ToggleButton toggle = ...
toggle.setOnTouchListener(new ToggleButton.OnTouchListener() {

  @Override
  public boolean onTouch(View v, MotionEvent event) {
     // If true is returned, the event is eated by the TouchListener
     return !v.isClickable();
  }
});

回答4:

Views can also respond to external keyboards, directional pads (remote/gaming controllers), and assistive devices (switch, screen readers).

回答5:

The differences is listed above, but there is a tip. use setClickable() after setOnClickListener(). Because of this:

public void setOnClickListener(@Nullable OnClickListener l) {
    if (!isClickable()) {
        setClickable(true);
    }
    getListenerInfo().mOnClickListener = l;
}

回答6:

setClickable public void setClickable (boolean clickable)

It enables or disables click events for the particular view. When a view is clickable it will change its state to "pressed" on every click. if this property of view is disabled then it will not change its state.

setEnabled public void setEnabled (boolean enabled)

It set the enabled state of this view .If the particular view is set to be enabled then pass true in the parameter else pass false