Android 4.0 UI for Tablet and Handset

Android 4.0(ICS) merge handset and tablet UI together, make customer flexible to use which UI they want. On marketing nowdays, phone use phone mode directly and other product like tablet/MID/PND use tablet mode.

ICS support multi-panel in tablet mode to fully use advantage of large screen size which is the major difference with former Android version.

Following layout gives us a brief knowledge about ICS UI:

+-------------------------------------------------+
| System bar (only in phone UI)                      |
+-------------------------------------------------+
| (Layout with background drawable)               |
| +---------------------------------------------+ |
| | Title/Action? bar (optional)                          |
| +---------------------------------------------+ |
| | Content, vertical extending                        |
| |                                                                |
| +---------------------------------------------+ |
+-------------------------------------------------+
| System bar (only in tablet UI)                       |
+-------------------------------------------------+

config_statusBarComponent choose which resource we want, statusBar or systemBar.if phone, use com.android.systemui.statusbar.phone.PhoneStatusBar?; while tablet, use com.android.systemui.statusbar.tablet.TabletStatusBar?. frameworks/base/packages/SystemUI/src/com/android/systemui/SystemUIService.java

    public void onCreate() {
        // Pick status bar or system bar.
        IWindowManager wm = IWindowManager.Stub.asInterface(
                ServiceManager.getService(Context.WINDOW_SERVICE));
        try {
            SERVICES[0] = wm.canStatusBarHide()
                    ? R.string.config_statusBarComponent
                    : R.string.config_systemBarComponent;
        } catch (RemoteException e) {
            Slog.w(TAG, "Failing checking whether status bar can hide", e);
        }

res/values/config.xml

<string name="config_statusBarComponent" translatable="false">
             com.android.systemui.statusbar.phone.PhoneStatusBar</string>
<string name="config_systemBarComponent" translatable="false">
             com.android.systemui.statusbar.tablet.TabletStatusBar<string> 

canStatusBarHide defined inframeworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

    public boolean canStatusBarHide() {
        return mStatusBarCanHide;
    }

mStatusBarCanHide true or false determine status bar or system bar.

        int shortSizeDp = shortSize
                * DisplayMetrics.DENSITY_DEFAULT
                / DisplayMetrics.DENSITY_DEVICE;
        mStatusBarCanHide = shortSizeDp < 600;
        mStatusBarHeight = mContext.getResources().getDimensionPixelSize(
                mStatusBarCanHide
                ? com.android.internal.R.dimen.status_bar_height
                : com.android.internal.R.dimen.system_bar_height);

Here if shortSizeDp smaller than 600, then system use as tablet mode, otherwise phone mode. DENSITY_DEFAULT is fixed 160. Therefore, 800*480 resolution which compute as 480*160/DENSITY_DEVICE and 800*600 compute as 600*160/DENSITY_DEVICE. So 120 should be suitable value to make both needs the tablet condition.

setprop ro.sf.lcd_density 120

frameworks/base/core/java/android/content/res/Configuration.java system configuration

public static final int SCREENLAYOUT_SIZE_SMALL = 0x01; 
public static final int SCREENLAYOUT_SIZE_NORMAL = 0x02; 
public static final int SCREENLAYOUT_SIZE_LARGE = 0x03; 
public static final int SCREENLAYOUT_SIZE_XLARGE = 0x04;

ICS also has three common software virtual key BACK, HOME and RECENT, default tablet mode appear while phone mode should modify code to adapt these keys. framework/base/packages/SystemUI/res/layout/navigation_bar.xml