Android 7.1 虚拟按键(NavigationBar)源码分析 控件加载、属性控制隐藏

 https://blog.csdn.net/kuaiguixs/article/details/78291695   Android 7.0 虚拟按键（NavigationBar）源码分析 之 View的创建流程 

一.主要的几个类

    //实现 单个虚拟按键的 自定义ImageView

    frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/KeyButtonView.java

    //虚拟按键的容器，实现整个 虚拟导航条的 自定义LinearLayout

    frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java

    //动态加载虚拟按键，放入NavigationBarView

    frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarInflaterView.java

    //虚拟导航条对应的布局文件

    frameworks/base/packages/SystemUI/res/layout/navigation_bar.xml

    //实现虚拟按键的点击效果

    frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java

  二.  inflateNavigationBarView 方法，它加载了布局 R.layout.navigation_bar，作为虚拟按键的容器 属性控制隐藏

--- a/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarInflaterView.java
+++ b/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarInflaterView.java
@@ -32,6 +32,7 @@ import android.widget.Space;
 import com.android.systemui.R;
 import com.android.systemui.statusbar.policy.KeyButtonView;
 import com.android.systemui.tuner.TunerService;
+import android.os.SystemProperties;
 
 import java.util.Objects;
 public class NavigationBarInflaterView extends FrameLayout implements TunerService.Tunable {
@@ -265,45 +266,59 @@ public class NavigationBarInflaterView extends FrameLayout implements TunerServi
         String button = extractButton(buttonSpec);
         View v = null;
         if (HOME.equals(button)) {
-            v = inflater.inflate(R.layout.home, parent, false);
-            if (landscape && isSw600Dp()) {
-                setupLandButton(v);
-            }
+        	if(SystemProperties.get("persist.navi.home","true").equals("true")){
+	        		v = inflater.inflate(R.layout.home, parent, false);
+	            if (landscape && isSw600Dp()) {
+	                setupLandButton(v);
+	            }
+        		}            
         } else if (BACK.equals(button)) {
+        	if(SystemProperties.get("ro.navi.back","true").equals("true")){
             v = inflater.inflate(R.layout.back, parent, false);
             if (landscape && isSw600Dp()) {
                 setupLandButton(v);
             }
+          }
         } else if (RECENT.equals(button)) {
+        	if(SystemProperties.get("ro.navi.recent","true").equals("true")){
             v = inflater.inflate(R.layout.recent_apps, parent, false);
             if (landscape && isSw600Dp()) {
                 setupLandButton(v);
             }
+          }
         } else if (SCREENSHOT.equals(button)) {
             v = inflater.inflate(R.layout.screenshot, parent, false);
             if (landscape && isSw600Dp()) {
                 setupLandButton(v);
             }
         } else if (VOLUME_ADD.equals(button)) {
+        	if(SystemProperties.get("ro.navi.volume_add","true").equals("true")){
             v = inflater.inflate(R.layout.volume_add, parent, false);
             if (landscape && isSw600Dp()) {
                 setupLandButton(v);
             }
+          }
         } else if (VOLUME_SUB.equals(button)) {
+        	if(SystemProperties.get("ro.navi.volume_sub","true").equals("true")){
             v = inflater.inflate(R.layout.volume_sub, parent, false);
             if (landscape && isSw600Dp()) {
                 setupLandButton(v);
             }
+          }
         }else if (POWER_DOWN.equals(button)) {
+        	if(SystemProperties.get("ro.navi.powerdown","true").equals("true")){
             v = inflater.inflate(R.layout.powerdown, parent, false);
             if (landscape && isSw600Dp()) {
                 setupLandButton(v);
             }
+          }
         }else if (HIDE_BAR.equals(button)) {
+        	if(SystemProperties.get("ro.navi.hide_bar","true").equals("true")){
             v = inflater.inflate(R.layout.hide_bar, parent, false);
             if (landscape && isSw600Dp()) {
                 setupLandButton(v);
             }
+          }
         } else if (MENU_IME.equals(button)) {
             v = inflater.inflate(R.layout.menu_ime, parent, false);
         } else if (NAVSPACE.equals(button)) {
@@ -321,6 +336,9 @@ public class NavigationBarInflaterView extends FrameLayout implements TunerServi
         } else {
             return null;
         }
+        if(v == null){
+        	return null;
+        }
 
         if (size != 0) {
             ViewGroup.LayoutParams params = v.getLayoutParams();