How to programmatically pause an activity?

How can I programmatically pause an activity? I have a TabHost that is creating an activity through an Intent:

Intent intent;  // Reusable Intent for each tab

        // Create an Intent to launch an Activity for the tab (to be reused)
        intent = new Intent().setClass(this, ARActivity.class);
        intent.putExtras(b);

        // Initialize a TabSpec for each tab and add it to the TabHost
        spec = tabHost.newTabSpec("trending").setIndicator("Trending",res.getDrawable(R.drawable.icon)).setContent(intent);
        tabHost.addTab(spec);

I want to be able to pause the activity when my tab changes. How can I pragmatically开发者_如何转开发 pause an activity?

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Activity will always be paused if it is not in view. Read here http://developer.android.com/guide/topics/fundamentals.html#actlife