How to create a view similar to the system notification area in android?

I'd like to have a view in my activity, which initially stays at the 开发者_StackOverflowtop of the screen like a little bar, but when you tap on it it should expand down, like the system notification area.

I haven't found any standard controls with such behaviour. What's the best way to implement this?

Use a SlidingDrawer. Here is a good tutorial.

The SlidingDrawer works exactly in this way.

The problem is that the SlidingDrawer can't be positioned at the top of the screen — it opens only upwards (see related question). So I implemented a simple control of my own, using the TranslateAnimation

class MySlidingDrawer extends LinearLayout {
    public static final int STATE_OPENED = 0;
    public static final int STATE_CLOSED = 1;

    private int m_intState;
    private LinearLayout m_content;
    private ImageButton m_handle;

    public MySlidingDrawer(Context context) {
        super(context);
        setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        setOrientation(VERTICAL);
        setGravity(Gravity.CENTER);

        m_content = new LinearLayout(context);
            // add your content here
        addView(m_content);
        m_intState = STATE_CLOSED;

        m_handle = new ImageButton(context);
        m_handle.setImageResource(R.drawable.icon);
        m_handle.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                toggleState();
            }
        });
        m_handle.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        addView(m_handle);
    }
    private int getContentHeight() {
        return m_content.getHeight();
    }
    private void toggleState() {
        int intYStart = 0;
        int intYEnd = m_intState == STATE_OPENED ? -getContentHeight() : getContentHeight();
        Animation a = new TranslateAnimation(0.0f, 0.0f, intYStart, intYEnd);
        a.setDuration(1000);
        a.setStartOffset(300);
        a.setInterpolator(AnimationUtils.loadInterpolator(getContext(), android.R.anim.bounce_interpolator));
        startAnimation(a);
        m_intState = m_intState == STATE_OPENED ? STATE_CLOSED : STATE_OPENED;
    }

    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);
        offsetTopAndBottom(-getContentHeight()); // content is initially invisible
    }
    protected void onAnimationEnd() {
        super.onAnimationEnd();
        int intYOffset = m_intState == STATE_OPENED ? getContentHeight() : -getContentHeight(); 
        offsetTopAndBottom(intYOffset);
    }
}

You can use the code posted in this answer: Android SlidingDrawer from top?

The provided solution features setting the orientation of the Slidingdrawer in xml also it's simple requiring only 1 class and some additions in attrs.xml and stable since it's derived from Androids Slidingdrawer from SDK. I also discuss why I didn't choose other popular libs/solutions found on the internet/SO.

Quicklink to the gist: MultipleOrientationSlidingDrawer (source & example) @ gist