Android 12 自定义底部导航栏

1.修改配置文件 frameworks\base\packages\SystemUI\res\values\config.xml

<!-- Nav bar button default ordering/layout -->
    <string name="config_navBarLayout" translatable="false">left[.5W];leftrotate,volume_sub,back,home,recent,volume_add,screenshot,rightrotate,setting,hidenav;right[.5W]</string>
    <string name="config_navBarLayoutQuickstep" translatable="false">back[1.7WC];home;contextual[1.7WC]</string>
    <string name="config_navBarLayoutHandle" translatable="false">back[70AC];home_handle;ime_switcher[70AC]</string>

添加自己新增加的button名称 

同步修改 frameworks\base\packages\SystemUI\res\values-sw600dp\config.xml   frameworks\base\packages\SystemUI\res\values-sw900dp\config.xml文件夹

sw是smallwidth的意思，当屏幕的最小边像素大于900 就会使用values-sw900dp\config.xml 

2.为新添加的button 创建layout布局 放在layout文件夹下 

<com.android.systemui.navigationbar.buttons.KeyButtonView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:systemui="http://schemas.android.com/apk/res-auto"
    android:id="@+id/hidenav"  button id
    android:layout_width="@dimen/navigation_key_width"
    android:layout_height="match_parent"
    android:layout_weight="0"
    systemui:keyCode="29"  很重要 指定keyCode 用于响应点击事件
    android:scaleType="center"
    android:paddingStart="@dimen/navigation_key_padding"
    android:paddingEnd="@dimen/navigation_key_padding"
    />

3.修改SystemUI Java源码 

frameworks\base\packages\SystemUI\src\com\android\systemui\navigationbar\NavigationBarInflaterView.java

在 createView里 加载button对应的layout文件 

else if (SETTING.equals(button)) {
            v = inflater.inflate(R.layout.setting, parent, false);
        }else if (HIDE.equals(button)) {
            v = inflater.inflate(R.layout.hidenav, parent, false);
        }

frameworks\base\packages\SystemUI\src\com\android\systemui\navigationbar\NavigationBarView.java

在构造方法中 添加button

mButtonDispatchers.put(R.id.left, new ButtonDispatcher(R.id.left));
mButtonDispatchers.put(R.id.right, new ButtonDispatcher(R.id.right));
mButtonDispatchers.put(R.id.setting, new ButtonDispatcher(R.id.setting));
mButtonDispatchers.put(R.id.hidenav, new ButtonDispatcher(R.id.hidenav));

定义新增加的Button

private KeyButtonDrawable mLeft;
private KeyButtonDrawable mRight;
private KeyButtonDrawable mSetting;
private KeyButtonDrawable mHide;

并在updateIcons方法中 为KeyButtonDrawable  指定 资源文件

    private void updateIcons(Configuration oldConfig) {
        final boolean orientationChange = oldConfig.orientation != mConfiguration.orientation;
        final boolean densityChange = oldConfig.densityDpi != mConfiguration.densityDpi;
        final boolean dirChange = oldConfig.getLayoutDirection() != mConfiguration.getLayoutDirection();

        if (orientationChange || densityChange) {
            mDockedIcon = getDrawable(R.drawable.ic_sysbar_docked);
            mHomeDefaultIcon = getHomeDrawable();
        }
        if (densityChange || dirChange) {
            mRecentIcon = getDrawable(R.drawable.ic_sysbar_recent);
            mContextualButtonGroup.updateIcons(mLightIconColor, mDarkIconColor);
        }
        if (orientationChange || densityChange || dirChange) {
            mBackIcon = getBackDrawable();
        }

        mVolumeAddIcon = getDrawable(R.drawable.ic_sysbar_volume_add_button);
        mVolumeSubIcon = getDrawable(R.drawable.ic_sysbar_volume_sub_button);
        mScreenshotIcon = getDrawable(R.drawable.ic_sysbar_capture_button);
        mLeft = getDrawable(R.drawable.leftrotate);
        mRight = getDrawable(R.drawable.rightrotate);
        mSetting = getDrawable(R.drawable.settings);
        mHide = getDrawable(R.drawable.hide);
    }

创建 获取ButtonDispatcher 的方法

public ButtonDispatcher getHideButton() {
        return mButtonDispatchers.get(R.id.hidenav);
    }

在updateNavButtonIcons方法中 为button指定resource 和可见性

getLeftButton().setImageDrawable(mLeft);
getRightButton().setImageDrawable(mRight);
getHideButton().setImageDrawable(mHide);
getSettingsButton().setImageDrawable(mSetting);

getLeftButton().setVisibility(View.VISIBLE);
getRightButton().setVisibility(View.VISIBLE);
getHideButton().setVisibility(View.VISIBLE);
getSettingsButton().setVisibility(View.VISIBLE);

4.在frameworks\base\packages\SystemUI\src\com\android\systemui\navigationbar\buttons\KeyButtonView.java为button 的onTouchEvent方法处理button的点击事件

     case MotionEvent.ACTION_UP:
                final boolean doIt = isPressed() && !mLongClicked;
                setPressed(false);
                final boolean doHapticFeedback = (SystemClock.uptimeMillis() - mDownTime) > 150;
                if (showSwipeUI) {
                    if (doIt) {
                        // Apply haptic feedback on touch up since there is none on touch down
                        performHapticFeedback(HapticFeedbackConstants.VIRTUAL_KEY);
                        playSoundEffect(SoundEffectConstants.CLICK);
                    }
                } else if (doHapticFeedback && !mLongClicked) {
                    // Always send a release ourselves because it doesn't seem to be sent elsewhere
                    // and it feels weird to sometimes get a release haptic and other times not.
                    performHapticFeedback(HapticFeedbackConstants.VIRTUAL_KEY_RELEASE);
                }
                if (mCode != KEYCODE_UNKNOWN) {
                    Log.e("longjiang","mCode"+mCode);
                    int rightCount = 0;
                    int leftCount = 0;
                    if(mCode == 26){
                        rightCount++;
                        Log.e("longjiang","rightCount"+rightCount);
                        Settings.System.putInt(mContext.getContentResolver(),Settings.System.ACCELEROMETER_ROTATION, 0);
                        Settings.System.putInt(mContext.getContentResolver(),Settings.System.USER_ROTATION, (4-rightCount%4)%4);
                    }else if(mCode == 25){
                        leftCount++;
                        Log.e("longjiang","leftCount"+leftCount);
                        Settings.System.putInt(mContext.getContentResolver(),Settings.System.ACCELEROMETER_ROTATION, 0);
                        Settings.System.putInt(mContext.getContentResolver(),Settings.System.USER_ROTATION, leftCount%4);
                    }else if(mCode ==  27){
                        //通过目标APP的包名创建intent对象
                        Intent intent = mContext.getPackageManager().getLaunchIntentForPackage("com.android.settings");
                        // 这里如果intent为空，就说名没有安装要跳转的应用嘛
                        if (intent != null) {
                            //传参方式与Activity间跳转相同
                            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                            mContext.startActivity(intent);
                        } else {
                            //没有安装目标app应用
                        }
                    }else if(mCode ==  29){
                        SystemProperties.set("vendor.hide.nav","true");
                        // View gameView = mContext.getWindow().getDecorView();
                        // gameView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION); // hide nav bar
                        //gameView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_VISIBLE // show nav bar);
                    }
                    if (doIt) {
                        sendEvent(KeyEvent.ACTION_UP, 0);
                        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);
                    } else {
                        sendEvent(KeyEvent.ACTION_UP, KeyEvent.FLAG_CANCELED);
                    }
                } else {
                    // no key code, just a regular ImageView
                    if (doIt && mOnClickListener != null) {
                        mOnClickListener.onClick(this);
                        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);
                    }
                }
                removeCallbacks(mCheckLongPress);
                break;
        }