实现小功能：最后一个fragment，按返回键，弹出退出提示框

在FragmentActivity重写onKeyDown方法：

@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		// TODO Auto-generated method stub
		if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN) {
			//if no more history in stack
			if (this.getSupportFragmentManager().getBackStackEntryCount() == 0) { 
				new AlertDialog.Builder(this).setMessage("退出程序？").setNegativeButton("取消", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						// TODO Auto-generated method stub
					}
				})
				.setPositiveButton("确定", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						finish();  
					}
				})
				.create().show();
				return true;
			}
		}
		return super.onKeyDown(keyCode, event);
	}

实现小功能：最后一个fragment，按返回键，弹出退出提示框

原文：http://blog.csdn.net/zi413293813/article/details/18324585