底部导航栏NavigationBar动态显示和隐藏
大家都知道，Android从3.0版本开始就加入了NavigationBar，主要是为那些没有实体按键的设备提供虚拟按键，但是，它始终固定在底部，占用48dp的像素高度，尽管从android 4.4开始可以全透明，使用这一部分像素，但三个按钮始终悬浮在屏幕上，这对于有强迫症的朋友来说是无法忍受的。因此，本文的目的就是修改framework部分代码，可以动态隐藏和显示NavigationBar，同时又尽量不影响系统的正常。
主要思路：
在NavigationBar的布局左部加入一个Button(在SystemUI模块实现)，点击隐藏NavigationBar，即将NavigationBar从WindowManager中移除掉。需要的时候，通过一个从屏幕底部向上的滑动手势(在policy模块实现)调出NavigationBar。如下两图对比所示：一张为移除前，另一张为移除后。
具体实现：
①.增加按钮实现动态隐藏，主要修改在frameworks/base/packages/SystemUI模块，首先我们增加一个按钮，主要修改
frameworks/base/packages/SystemUI/res/layout/navigation_bar.xml文件，图片资源和字符串我就不提了，具体如下：
diff --git a/frameworks/base/packages/SystemUI/res/layout/navigation_bar.xml b/frameworks/base/packages/SystemUI/res/layout/navigation_bar.xml
index 16027d9..326aafc 100644
--- a/frameworks/base/packages/SystemUI/res/layout/navigation_bar.xml
+++ b/frameworks/base/packages/SystemUI/res/layout/navigation_bar.xml
@@ -42,12 +42,28 @@
>
<!-- navigation controls -->
+ <!--BEGIN liweiping
<View
android:layout_width=40dp
android:layout_height=match_parent
android:layout_weight=0
android:visibility=invisible
/>
+ -->
+ <framelayout android:layout_height="match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_extra_key_width">
+ <imagebutton android:contentdescription="@string/accessibility_hide" android:id="@+id/hide_bar_btn" android:layout_height="match_parent" android:layout_width="@dimen/navigation_extra_key_width" android:src="@drawable/ic_sysbar_hide">
+
+ </imagebutton></framelayout>
+ <!--END liweiping -->
<com.android.systemui.statusbar.policy.keybuttonview 12="" 28="" android:contentdescription="@string/accessibility_back" android:id="@+id/back" android:layout_height="match_parent" android:layout_weight="0" android:layout_width="@dimen/navigation_key_width">
+ <!--BEGIN liweiping
<View
android:layout_height=40dp
android:layout_width=match_parent
android:layout_weight=0
android:visibility=invisible
/>
+ -->
+ <framelayout android:layout_height="40dp" android:layout_weight="0" android:layout_width="match_parent">
+
+ <imagebutton android:contentdescription="@string/accessibility_hide" android:id="@+id/hide_bar_btn" android:layout_height="40dp" android:layout_width="match_parent" android:src="@drawable/ic_sysbar_hide_land">
+ </imagebutton></framelayout>
+ <!--END liweiping -->
<!-- lights out layout to match exactly --></com.android.systemui.statusbar.policy.keybuttonview>
接下来修改frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java，为按钮提供一个接口，具体如下：
diff --git a/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java b/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java
index 88e71e2..7545984 100644
--- a/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java
+++ b/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java
@@ -45,6 +45,7 @@ import com.android.systemui.R;
import com.android.systemui.statusbar.BaseStatusBar;
import com.android.systemui.statusbar.DelegateViewHelper;
import com.android.systemui.statusbar.policy.DeadZone;
+import com.android.systemui.statusbar.policy.KeyButtonRipple;
import com.android.systemui.statusbar.policy.KeyButtonView;
import java.io.FileDescriptor;
@@ -265,6 +266,13 @@ public class NavigationBarView extends LinearLayout {
public View getImeSwitchButton() {
return mCurrentView.findViewById(R.id.ime_switcher);
}
+ //BEGIN liweiping
+ public View getHideBarButton() {
+ View view = mCurrentView.findViewById(R.id.hide_bar_btn);
+ view.setBackground(new KeyButtonRipple(getContext(), view));
+ return view;
+ }
+ //END liweiping
private void getIcons(Resources res) {
mBackIcon = res.getDrawable(R.drawable.ic_sysbar_back);
@@ -412,7 +420,6 @@ public class NavigationBarView extends LinearLayout {
mCurrentView = mRotatedViews[Surface.ROTATION_0];
getImeSwitchButton().setOnClickListener(mImeSwitcherClickListener);
-
updateRTLOrder();
}
最后便是在frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java实现点击事件了
+ private final OnClickListener mHideBarClickListener = new OnClickListener() {
+ @Override
+ public void onClick(View view) {
+ Log.i(way, mHideBarClickListener onClick...);
+ removeNavigationBar();
+ }
+ };
+ private void removeNavigationBar() {
+ if (DEBUG) Log.d(TAG, removeNavigationBar: about to remove + mNavigationBarView);
+ if (mNavigationBarView == null) return;
+
+ mWindowManager.removeView(mNavigationBarView);
+ mNavigationBarView = null;
+ }
到此，隐藏NavigationBar告一段落了。
②.接下来便是显示NavigationBar，这个修改相对复杂一点。因为此时NavigationBar处于不可见状态，我们无法通过增加按钮的方式让其显示，但是我们知道，状态栏下拉通过手势向下滑动即可。因此很容易便想到通过手势从屏幕底部向上滑动来显示NavigationBar。我的想法是在policy模块中增加一个接口，通过frameworks/base/services/core/java/com/android/server/statusbar/StatusBarManagerService.java服务传递到状态栏中，从而触发显示NavigationBar事件。
也许大家会有疑问，为什么是在policy模块修改？其实我这只是一种解决方案，因为我知道
frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java 有现成的手势滑动接口。其实你也可以SystemUI中增加一个这样的事件，我们需要的就是这么一个触发事件。
PhoneWindowManager.java的修改主要是实现onSwipeFromBottom(竖屏时)和onSwipeFromRight(横屏时)两个接口，然后调用showNavigationBar，在showNavigationBar函数中，我们调用StatusBarManagerService服务中的showNavigationBar函数，具体如下：
diff --git a/frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java b/frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
index bb53e12..907202d 100644
--- a/frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
+++ b/frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
@@ -1241,13 +1241,27 @@ public class PhoneWindowManager implements WindowManagerPolicy {
public void onSwipeFromBottom() {
if (mNavigationBar != null && mNavigationBarOnBottom) {
requestTransientBars(mNavigationBar);
+ Log.i(way, onSwipeFromBottom... mNavigationBar != null && mNavigationBarOnBottom);
}
+ //BEGIN liweiping
+ else{
+ Log.i(way, onSwipeFromBottom...);
+ showNavigationBar();
+ }
+ //END liweiping
}
@Override
public void onSwipeFromRight() {
if (mNavigationBar != null && !mNavigationBarOnBottom) {
requestTransientBars(mNavigationBar);
+ Log.i(way, onSwipeFromRight... mNavigationBar != null && !mNavigationBarOnBottom);
+ }
+ //BEGIN liweiping
+ else{
+ Log.i(way, onSwipeFromRight...);
+ showNavigationBar();
}
+ //END liweiping
}
@Override
public void onDebug() {
@@ -1293,7 +1307,24 @@ public class PhoneWindowManager implements WindowManagerPolicy {
goingToSleep(WindowManagerPolicy.OFF_BECAUSE_OF_USER);
}
}
-
+ //BEGIN liweiping
+ private void showNavigationBar(){
+ mHandler.post(new Runnable() {
+ @Override
+ public void run() {
+ try {
+ IStatusBarService statusbar = getStatusBarService();
+ if (statusbar != null) {
+ statusbar.showNavigationBar();
+ }
+ } catch (RemoteException e) {
+ // re-acquire status bar service next time it is needed.
+ mStatusBarService = null;
+ }
+ }
+ });
+ }
+ //END liweiping
private void updateKeyAssignments() {
final boolean hasMenu = (mDeviceHardwareKeys & KEY_MASK_MENU) != 0;
final boolean hasHome = (mDeviceHardwareKeys & KEY_MASK_HOME) != 0;
这时事件传递到了StatusBarManagerService中，我们来看看StatusBarManagerService.java如何实现showNavigationBar：
diff --git a/frameworks/base/services/core/java/com/android/server/statusbar/StatusBarManagerService.java b/frameworks/base/services/core/java/com/android/server/statusbar/StatusBarManagerService.java
index f85e2d9..3f75840 100644
--- a/frameworks/base/services/core/java/com/android/server/statusbar/StatusBarManagerService.java
+++ b/frameworks/base/services/core/java/com/android/server/statusbar/StatusBarManagerService.java
@@ -366,6 +366,27 @@ public class StatusBarManagerService extends IStatusBarService.Stub {
WindowManager.LayoutParams);
}
}
+ //BEGIN liweiping
+ @Override
+ public void showNavigationBar() {
+ enforceStatusBar();
+
+ android.util.Log.d(way, TAG + showNavigationBar...);
+
+ synchronized(mLock) {
+ mHandler.post(new Runnable() {
+ public void run() {
+ if (mBar != null) {
+ try {
+ mBar.showNavigationBar();
+ } catch (RemoteException ex) {
+ }
+ }
+ }
+ });
+ }
+ }
+ //END liweiping
private void updateUiVisibilityLocked(final int vis, final int mask) {
if (mSystemUiVisibility != vis) {
从上述代码可以看出，StatusBarManagerService只是起到一个传递作用，将消息传递到StatusBar中，最终的实现是在SystemUI模块的frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java，如下所示：
diff --git a/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java b/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
index 9db875f..4f24b6e 100644
--- a/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
+++ b/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
@@ -56,6 +56,7 @@ public class CommandQueue extends IStatusBar.Stub {
private static final int MSG_BUZZ_BEEP_BLINKED = 15 << MSG_SHIFT;
private static final int MSG_NOTIFICATION_LIGHT_OFF = 16 << MSG_SHIFT;
private static final int MSG_NOTIFICATION_LIGHT_PULSE = 17 << MSG_SHIFT;
+ private static final int MSG_SHOW_NAVIGATIONBAR = 18 << MSG_SHIFT;//ADD liweiping
public static final int FLAG_EXCLUDE_NONE = 0;
public static final int FLAG_EXCLUDE_SEARCH_PANEL = 1 << 0;
@@ -83,6 +84,7 @@ public class CommandQueue extends IStatusBar.Stub {
public void animateCollapsePanels(int flags);
public void animateExpandSettingsPanel();
public void setSystemUiVisibility(int vis, int mask);
+ public void showNavigationBar();//ADD liweiping
public void topAppWindowChanged(boolean visible);
public void setImeWindowStatus(IBinder token, int vis, int backDisposition,
boolean showImeSwitcher);
@@ -154,6 +156,14 @@ public class CommandQueue extends IStatusBar.Stub {
mHandler.obtainMessage(MSG_SET_SYSTEMUI_VISIBILITY, vis, mask, null).sendToTarget();
}
}
+ //BEGIN liweiping
+ public void showNavigationBar() {
+ synchronized (mList) {
+ mHandler.removeMessages(MSG_SHOW_NAVIGATIONBAR);
+ mHandler.sendEmptyMessage(MSG_SHOW_NAVIGATIONBAR);
+ }
+ }
+ //END liweiping
public void topAppWindowChanged(boolean menuVisible) {
synchronized (mList) {
@@ -283,6 +293,11 @@ public class CommandQueue extends IStatusBar.Stub {
case MSG_SET_SYSTEMUI_VISIBILITY:
mCallbacks.setSystemUiVisibility(msg.arg1, msg.arg2);
break;
+ //BEGIN liweiping
+ case MSG_SHOW_NAVIGATIONBAR:
+ mCallbacks.showNavigationBar();
+ break;
+ //END liweiping
case MSG_TOP_APP_WINDOW_CHANGED:
mCallbacks.topAppWindowChanged(msg.arg1 != 0);
break;
CommandQueue.java收到了这个消息之后，又回调给了base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java，绕了大半天，消息终于回来了，我们就是需要在PhoneStatusBar.java实现显示NavigationBar的函数了：
+ @Override // CommandQueue
+ public void showNavigationBar() {
+ Log.i(way, TAG + showNavigationBar...);
+ forceAddNavigationBar();
+ }
+ private void forceAddNavigationBar() {
+ // If we have no Navbar view and we should have one, create it
+ if (mNavigationBarView != null) {
+ return;
+ }
+
+ mNavigationBarView =
+ (NavigationBarView) View.inflate(mContext, R.layout.navigation_bar, null);
+ mNavigationBarView.setDisabledFlags(mDisabled);
+ mNavigationBarView.setBar(this);
+ addNavigationBar(true); // dynamically adding nav bar, reset System UI visibility!
+ }
+ private void prepareNavigationBarView(boolean forceReset) {
+ mNavigationBarView.reorient();
+ mNavigationBarView.getRecentsButton().setOnClickListener(mRecentsClickListener);
+ mNavigationBarView.getRecentsButton().setOnTouchListener(mRecentsPreloadOnTouchListener);
+ mNavigationBarView.getRecentsButton().setLongClickable(true);
+ mNavigationBarView.getRecentsButton().setOnLongClickListener(mLongPressBackRecentsListener);
+ mNavigationBarView.getBackButton().setLongClickable(true);
+ mNavigationBarView.getBackButton().setOnLongClickListener(mLongPressBackRecentsListener);
+ mNavigationBarView.getHomeButton().setOnTouchListener(mHomeActionListener);
+ mNavigationBarView.getHideBarButton().setOnClickListener(mHideBarClickListener);//ADD liweiping
+
+ if (forceReset) {
+ // Nav Bar was added dynamically - we need to reset the mSystemUiVisibility and call
+ // setSystemUiVisibility so that mNavigationBarMode is set to the correct value
+ Log.i(way, prepareNavigationBarView mNavigationBarMode = + mNavigationBarMode + mSystemUiVisibility = + mSystemUiVisibility + mNavigationIconHints = + mNavigationIconHints);
+ mNavigationBarMode = 0;
+
+ int newVal = mSystemUiVisibility;
+ mSystemUiVisibility = View.SYSTEM_UI_FLAG_VISIBLE;
+ setSystemUiVisibility(newVal, /*SYSTEM_UI_VISIBILITY_MASK*/0xffffffff);
+ int hints = mNavigationIconHints;
+ mNavigationIconHints = 0;
+ setNavigationIconHints(hints);
+ topAppWindowChanged(mShowMenu);
+ }
+
+ updateSearchPanel();
+ }
+
+ // For small-screen devices (read: phones) that lack hardware navigation buttons
+ private void addNavigationBar(boolean forceReset) {
+ if (DEBUG) Log.v(TAG, addNavigationBar: about to add + mNavigationBarView);
+ if (mNavigationBarView == null) return;
+
+ prepareNavigationBarView(forceReset);
+
+ mWindowManager.addView(mNavigationBarView, getNavigationBarLayoutParams());
+ }
+ //END liweiping
需要注意的是： ①显示NavigationBar时，需要重新实例化一次NavigationBarView，我之前有试过移除NavigationBarView后未置空，下次添加时直接使用，会出现状态栏重启的情况，具体原因未知，log显示动画播放错误之类。 ②重新添加NavigationBarView时需要恢复NavigationBarView之前的状态，比如说隐藏前时是透明的、显示输入法按钮、菜单键等等。 ③本文是在Android5.0的代码上修改的，其他版本未验证。 ④本文仅是提供一种思路，并非最优方案。