Android 4.0 平板全屏实现(二)
来自：http://www.eoeandroid.com/thread-246825-1-1.html
在上一篇 Android 4.0 平板全屏实现(一) 中，实现了android 4.0 上平板的导航栏的“不可见”，即所有的导航键都不显示，但导航栏所占的区域大小还在，只是显示成一个黑条，这显然不是我们想要的效果。本着打破沙锅问到底的精神，笔者继续翻源码，查阅相关资料，发现4.0 以后的导航栏都是被 SystemUI.apk 的应用控制的，它的源码所在的位置：
frameworks/base/packages/SystemUI
在SystemUI 启动流程一文中对 SystemUI 有详细的介绍，在这里就不再赘述，各位看官可移步了解之。废话不多说，开始回到正题。我们最终想要得到的效果，就是完全隐藏平板上的导航栏，没有占用任何显示空间。
SystemUI 的启动过程（平板部分）
在Android 4.0 ICS SystemUI浅析——SystemUI启动流程这篇文章中做了详细的介绍，挑几个重要的步骤来讲：
1.
SystemServer 在开机之后启动SystemUIService
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static
final
void
startSystemUi(Context context) {
Intent intent =
new
Intent();
intent.setComponent(
new
ComponentName(
"com.android.systemui"
,
"com.android.systemui.SystemUIService"
));
Slog.d(TAG,
"Starting service: "
+ intent);
context.startService(intent);
}
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2. SystemUIService 启动两个继承自 SystemUI 的 "service", 其中 导航栏的类是根据屏幕分辨率来判断的
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// Pick status bar or system bar.
IWindowManager wm = IWindowManager.Stub.asInterface(
ServiceManager.getService(Context.WINDOW_SERVICE));
try
{
Log.d(TAG,
"*** canStatusBarHide = "
+ wm.canStatusBarHide() +
" ***"
);
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);
}
final
int
N = SERVICES.length;
mServices =
new
SystemUI[N];
for
(
int
i=
0
; i<N; i++) {
Class cl = chooseClass(SERVICES<i>);
Slog.d(TAG,
"loading: "
+ cl);
try
{
mServices<i> = (SystemUI)cl.newInstance();
}
catch
(IllegalAccessException ex) {
throw
new
RuntimeException(ex);
}
catch
(InstantiationException ex) {
throw
new
RuntimeException(ex);
}
mServices<i>.mContext =
this
;
Slog.d(TAG,
"running: "
+ mServices<i>);
mServices<i>.start();
}
</i></i></i></i></i>
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如果是平板（wm.canStatusBarHide() = false）则启用 com.android.systemui.statusbar.tablet.TabletStatusBar，这也是我们接下来研究的重点。因为手机已经可以做到完全全屏。
继续跟踪，发现 PhoneStatusBar 和 TabletStatusBar 都继承自 StatusBar, 在 StatusBar 中有一个非常重要的抽象函数 makeStatusBarView()，没错，看名字就可以知道，就是它初始化了SystemUI的主要部分（手机的是 NavigationBar 和 StatusBar, 平板的是 Combination bar）. 不管是手机还是平板，都是通过这个函数来生成自己的导航栏，被 StatusBar 调用，具体代码如下：
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public
void
start() {
// First set up our views and stuff.
View sb = makeStatusBarView();
// Connect in to the status bar manager service
StatusBarIconList iconList =
new
StatusBarIconList();
ArrayList<IBinder> notificationKeys =
new
ArrayList<IBinder>();
ArrayList<StatusBarNotification> notifications =
new
ArrayList<StatusBarNotification>();
mCommandQueue =
new
CommandQueue(
this
, iconList);
mBarService = IStatusBarService.Stub.asInterface(
ServiceManager.getService(Context.STATUS_BAR_SERVICE));
int
[] switches =
new
int
[
7
];
ArrayList<IBinder> binders =
new
ArrayList<IBinder>();
try
{
mBarService.registerStatusBar(mCommandQueue, iconList, notificationKeys, notifications,
switches, binders);
}
catch
(RemoteException ex) {
// If the system process isn't there we're doomed anyway.
}
disable(switches[
0
]);
setSystemUiVisibility(switches[
1
]);
topAppWindowChanged(switches[
2
] !=
0
);
// StatusBarManagerService has a back up of IME token and it's restored here.
setImeWindowStatus(binders.get(
0
), switches[
3
], switches[
4
]);
setHardKeyboardStatus(switches[
5
] !=
0
, switches[
6
] !=
0
);
// Set up the initial icon state
int
N = iconList.size();
int
viewIndex =
0
;
for
(
int
i=
0
; i<N; i++) {
StatusBarIcon icon = iconList.getIcon(i);
if
(icon !=
null
) {
addIcon(iconList.getSlot(i), i, viewIndex, icon);
viewIndex++;
}
}
// Set up the initial notification state
N = notificationKeys.size();
if
(N == notifications.size()) {
for
(
int
i=
0
; i<N; i++) {
addNotification(notificationKeys.get(i), notifications.get(i));
}
}
else
{
Log.wtf(TAG,
"Notification list length mismatch: keys="
+ N
+
" notifications="
+ notifications.size());
}
// Put up the view
final
int
height = getStatusBarHeight();
mStatusBarHeight = height;
final
WindowManager.LayoutParams lp =
new
WindowManager.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
height,
WindowManager.LayoutParams.TYPE_STATUS_BAR,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_TOUCHABLE_WHEN_WAKING
| WindowManager.LayoutParams.FLAG_SPLIT_TOUCH,
PixelFormat.OPAQUE);
// the status bar should be in an overlay if possible
final
Display defaultDisplay
= ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))
.getDefaultDisplay();
if
(ActivityManager.isHighEndGfx(defaultDisplay)) {
lp.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
}
lp.gravity = getStatusBarGravity();
lp.setTitle(
"StatusBar"
);
lp.packageName = mContext.getPackageName();
lp.windowAnimations = R.style.Animation_StatusBar;
mStatusBarLayoutParams = lp;
mStatusBarView = sb;
WindowManagerImpl.getDefault().addView(sb, lp);
if
(SPEW) {
Slog.d(TAG,
"Added status bar view: gravity=0x"
+ Integer.toHexString(lp.gravity)
+
" icons="
+ iconList.size()
+
" disabled=0x"
+ Integer.toHexString(switches[
0
])
+
" lights="
+ switches[
1
]
+
" menu="
+ switches[
2
]
+
" imeButton="
+ switches[
3
]
);
}
mDoNotDisturb =
new
DoNotDisturb(mContext);
}
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通过上面这段代码，可以看到，在调用makeStatusBarView生成View sb 之后，通过 WindowManagerImpl.getDefault().addView(sb, lp); 将其显示到屏幕之上。追踪到这里，我想大多数同学应该知道怎么去做导航栏的隐藏了。。
没错，很简单，调用 WindowManagerImpl.getDefault().updateView(sb, lp) 就可以搞定。如果是要导航栏始终不可见，将其高度设置为0就可以，但是我们还要将其还原。还得update回来。。
接下来的问题，就是要找个合适的位子，添加上我们的这段代码，在什么地方调用updateView才是最合适的呢？
全屏实现(4.0平板)
由于 StatusBar 是被 SystemUIService 调用的，而且仅仅执行 start() 函数，而 StatusBar 是个普通的Java类，没有Context上下文环境，不具备接收事件的能力(这里可能描述得不够清楚，主要就是说应用层发送的广播啊，startService之类的方法都不被StatusBar接收到。因为我们需要在应用层调用相关cmd来控制导航栏的显示/隐藏)。
我们会发现，SystemUIService 是个普通的 service 能够使用到组件之间的通信之中，并且StatusBar也是在这里被调起来的。开始动工吧，能想到的最简单的调用顺序就是 ：
1. 扩展 SystemUI, 添加多一个抽象函数 onReceive(String action)
2. 在 SystemUIService 中注册一个 BroadcastReceiver 监听我们定制的两个 action (隐藏/显示)
3. 在 BroadcastReceive 函数中，调用 SystemUI 的 onReceive函数
4. 在 StatusBar 的 onReceive 函数中处理导航栏的显示/隐藏。
在 SystemUI 中添加抽象函数（frameworks/base/packages/SystemUI/src/com/android/systemui/SystemUI.java）
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public
abstract
class
SystemUI {
public
Context mContext;
public
abstract
void
start();
<font color=
"#00f0f0"
>
public
abstract
void
onReceive(String action);</font>
protected
void
onConfigurationChanged(Configuration newConfig) {
}
public
void
dump(FileDescriptor fd, PrintWriter pw, String[] args) {
}
}
|
在 SystemUIService 中注册 BroadcastReceiver (frameworks/base/packages/SystemUI/src/com/android/systemui/SystemUIService.java)
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@Override
public
void
onCreate() {
// Pick status bar or system bar.
IWindowManager wm = IWindowManager.Stub.asInterface(
ServiceManager.getService(Context.WINDOW_SERVICE));
try
{
Log.d(TAG,
"*** canStatusBarHide = "
+ wm.canStatusBarHide() +
" ***"
);
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);
}
final
int
N = SERVICES.length;
mServices =
new
SystemUI[N];
for
(
int
i=
0
; i<N; i++) {
Class cl = chooseClass(SERVICES<i>);
Slog.d(TAG,
"loading: "
+ cl);
try
{
mServices<i> = (SystemUI)cl.newInstance();
}
catch
(IllegalAccessException ex) {
throw
new
RuntimeException(ex);
}
catch
(InstantiationException ex) {
throw
new
RuntimeException(ex);
}
mServices<i>.mContext =
this
;
Slog.d(TAG,
"running: "
+ mServices<i>);
mServices<i>.start();
}
<font color=
"#00f0f0"
>
// register broadcast receiver
IntentFilter intentFilter =
new
IntentFilter();
intentFilter.addAction(ACTION_DISPLAY_STATUS_BAR);
intentFilter.addAction(ACTION_HIDE_STATUS_BAR);
registerReceiver(mStatusBarReceiver, intentFilter);</font>
}</i></i></i></i></i>
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在 onReceive 中分发事件（frameworks/base/packages/SystemUI/src/com/android/systemui/SystemUIService.java）
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BroadcastReceiver mStatusBarReceiver =
new
BroadcastReceiver() {
@Override
public
void
onReceive(Context context, Intent intent) {
if
(intent !=
null
&& !TextUtils.isEmpty(intent.getAction())) {
String action = intent.getAction();
final
int
N = SERVICES.length;
for
(
int
i =
0
; i < N; i++) {
Slog.d(TAG,
"invoke: "
+ mServices<i> +
"'s onReceive()"
);
<font color=
"#00f0f0"
> mServices<i>.onReceive(action);</i></font><i>
}
}
}
};</i></i>
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在StatusBar中处理消息(frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/StatusBar.java)
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public
abstract
class
StatusBar
extends
SystemUI
implements
CommandQueue.Callbacks {
static
final
String TAG =
"StatusBar"
;
private
static
final
boolean
SPEW =
false
;
protected
CommandQueue mCommandQueue;
protected
IStatusBarService mBarService;
// Up-call methods
protected
abstract
View makeStatusBarView();
protected
abstract
int
getStatusBarGravity();
public
abstract
int
getStatusBarHeight();
public
abstract
void
animateCollapse();
private
DoNotDisturb mDoNotDisturb;
<font color=
"#00f0f0"
>
private
View mStatusBarView;
private
int
mStatusBarHeight;
private
WindowManager.LayoutParams mStatusBarLayoutParams;</font>
public
void
start() {
// First set up our views and stuff.
View sb = makeStatusBarView();
// Connect in to the status bar manager service
StatusBarIconList iconList =
new
StatusBarIconList();
ArrayList<IBinder> notificationKeys =
new
ArrayList<IBinder>();
ArrayList<StatusBarNotification> notifications =
new
ArrayList<StatusBarNotification>();
mCommandQueue =
new
CommandQueue(
this
, iconList);
mBarService = IStatusBarService.Stub.asInterface(
ServiceManager.getService(Context.STATUS_BAR_SERVICE));
int
[] switches =
new
int
[
7
];
ArrayList<IBinder> binders =
new
ArrayList<IBinder>();
try
{
mBarService.registerStatusBar(mCommandQueue, iconList, notificationKeys, notifications,
switches, binders);
}
catch
(RemoteException ex) {
// If the system process isn't there we're doomed anyway.
}
disable(switches[
0
]);
setSystemUiVisibility(switches[
1
]);
topAppWindowChanged(switches[
2
] !=
0
);
// StatusBarManagerService has a back up of IME token and it's restored here.
setImeWindowStatus(binders.get(
0
), switches[
3
], switches[
4
]);
setHardKeyboardStatus(switches[
5
] !=
0
, switches[
6
] !=
0
);
// Set up the initial icon state
int
N = iconList.size();
int
viewIndex =
0
;
for
(
int
i=
0
; i<N; i++) {
StatusBarIcon icon = iconList.getIcon(i);
if
(icon !=
null
) {
addIcon(iconList.getSlot(i), i, viewIndex, icon);
viewIndex++;
}
}
// Set up the initial notification state
N = notificationKeys.size();
if
(N == notifications.size()) {
for
(
int
i=
0
; i<N; i++) {
addNotification(notificationKeys.get(i), notifications.get(i));
}
}
else
{
Log.wtf(TAG,
"Notification list length mismatch: keys="
+ N
+
" notifications="
+ notifications.size());
}
// Put up the view
final
int
height = getStatusBarHeight();
<font color=
"#00f0f0"
> mStatusBarHeight = height;</font>
final
WindowManager.LayoutParams lp =
new
WindowManager.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
height,
WindowManager.LayoutParams.TYPE_STATUS_BAR,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_TOUCHABLE_WHEN_WAKING
| WindowManager.LayoutParams.FLAG_SPLIT_TOUCH,
PixelFormat.OPAQUE);
// the status bar should be in an overlay if possible
final
Display defaultDisplay
= ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))
.getDefaultDisplay();
if
(ActivityManager.isHighEndGfx(defaultDisplay)) {
lp.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
}
lp.gravity = getStatusBarGravity();
lp.setTitle(
"StatusBar"
);
lp.packageName = mContext.getPackageName();
lp.windowAnimations = R.style.Animation_StatusBar;
<font color=
"#00f0f0"
> mStatusBarLayoutParams = lp;
mStatusBarView = sb;</font>
WindowManagerImpl.getDefault().addView(sb, lp);
if
(SPEW) {
Slog.d(TAG,
"Added status bar view: gravity=0x"
+ Integer.toHexString(lp.gravity)
+
" icons="
+ iconList.size()
+
" disabled=0x"
+ Integer.toHexString(switches[
0
])
+
" lights="
+ switches[
1
]
+
" menu="
+ switches[
2
]
+
" imeButton="
+ switches[
3
]
);
}
mDoNotDisturb =
new
DoNotDisturb(mContext);
}
protected
View updateNotificationVetoButton(View row, StatusBarNotification n) {
View vetoButton = row.findViewById(R.id.veto);
if
(n.isClearable()) {
final
String _pkg = n.pkg;
final
String _tag = n.tag;
final
int
_id = n.id;
vetoButton.setOnClickListener(
new
View.OnClickListener() {
public
void
onClick(View v) {
try
{
mBarService.onNotificationClear(_pkg, _tag, _id);
}
catch
(RemoteException ex) {
// system process is dead if we're here.
}
}
});
vetoButton.setVisibility(View.VISIBLE);
}
else
{
vetoButton.setVisibility(View.GONE);
}
return
vetoButton;
}
<font color=
"#00f0f0"
>
@Override
public
void
onReceive(String action) {
Log.d(TAG,
"*** onReceive(), action = "
+ action +
" ***"
);
if
(SystemUIService.ACTION_DISPLAY_STATUS_BAR.equals(action)) {
mStatusBarLayoutParams.height = mStatusBarHeight;
WindowManagerImpl.getDefault().updateViewLayout(mStatusBarView,
mStatusBarLayoutParams);
}
else
if
(SystemUIService.ACTION_HIDE_STATUS_BAR.equals(action)) {
mStatusBarLayoutParams.height =
0
;
WindowManagerImpl.getDefault().updateViewLayout(mStatusBarView,
mStatusBarLayoutParams);
}</font>
}
}
|
至此，在SystemUI.apk 中的改动全部完成。
还没说完……在应用端 通过发送 broadcast 就可以控制导航栏的显示/隐藏了
具体调用如下：
全屏
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sendBroadcast(
new
Intent(
"com.android.action.HIDE_BAR"
));
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非全屏
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|
sendBroadcast(
new
Intent(
"com.android.action_DISPLAY_BAR"
));
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