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Android之framework修改底部导航栏NavigationBar动态显示和隐藏

时间：2024-3-2 17:17     作者：韩俊     分类： Android

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_width="@dimen/navigation_extra_key_width"
+                android:layout_height="match_parent"
+                android:layout_weight="0" >
+                <ImageButton
+                    android:id="@+id/hide_bar_btn"
+                    android:layout_width="@dimen/navigation_extra_key_width"
+                    android:layout_height="match_parent"
+                    android:contentDescription="@string/accessibility_hide"
+                    android:src="@drawable/ic_sysbar_hide"
+                     />
+
+            </FrameLayout>
+           <!--END liweiping -->
             <com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/back"
                 android:layout_width="@dimen/navigation_key_width"
                 android:layout_height="match_parent"
@@ -246,12 +262,28 @@
                 android:layout_weight="0"
                 android:contentDescription="@string/accessibility_back"
                 />
+           <!--BEGIN liweiping
             <View
                 android:layout_height="40dp"
                 android:layout_width="match_parent"
                 android:layout_weight="0"
                 android:visibility="invisible"
                 />
+           -->
+            <FrameLayout
+                android:layout_weight="0"
+                android:layout_width="match_parent"
+                android:layout_height="40dp" >
+
+                <ImageButton
+                    android:id="@+id/hide_bar_btn"
+                    android:layout_width="match_parent"
+                    android:layout_height="40dp"
+                    android:contentDescription="@string/accessibility_hide"
+                    android:src="@drawable/ic_sysbar_hide_land"
+                     />
+            </FrameLayout>
+           <!--END liweiping -->
         </LinearLayout>

         <!-- lights out layout to match exactly -->

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。

⑤转载请注明出处：http://blog.csdn.net/way_ping_li



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