how to change the view of a button onClick in android

In my app I am trying to calculate an operation using timer. For controlling those operations I am using four buttons as Start, Stop, Pause and resume.

But I want to show only 2 buttons. At the beginning I have only two buttons Start and Pause. When the start button is clicked timer gets started and immediately in Start button's place I want to show the Stop button.

I want to do the same for the other stop and pause buttons. How to 开发者_高级运维do this please help me......

Using ToggleButton is a good solution for you. Do something like:

ToggleButton first = new ToggleButton(getContext());
    ToggleButton second = new ToggleButton(getContext());
    first.setTextOff("start");
    first.setTextOn("stop");
    second.setTextOff("pause");
    second.setTextOn("resume");

and use setOnCheckedChangeListener() to implement your actions.

In your onClick(View v), v is the button that gets clicked. You can cast it like:

Button b = (Button) v;

so you can change its text with setText(), and set another listener. You can declare the alternate listeners once as members of the activity, and set them without re-declaring them each time.

Your application needs to maintain states, such as "Idle/Stopped", "In Progress", "Paused", etc. If you want to hide buttons, you can use View.setVisibility, and dynamically show and hide the buttons when your state changes (when other buttons are pressed). You would need to set your layout appropriately so that the buttons display nicely as they are shown/hidden dynamically

Or, you can change the text of the buttons, and their associated click listeners dynamically. This method is not very ideal becuase you may run in to cases where you want different amount of buttons for all your different states, and also, you're associating variable behavior with a single control. Also, you must manage your click listeners, adding and removing them dynamically.

here is a simple implementation

public class Demo extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    final Button button=(Button)findViewById(R.id.button);

    button.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
            button.setText("stop");
        }
    });
    }
}

In the main.xml have a Button widget like this,

<Button android:id="@+id/button"
android:text="start"
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
 />