Android 8.1(O) Launcher3相关修改(二)

1 hotseat位置：O版本有五个图标，Go版本有四个图标，它们之间的差别在哪？

在InvariantDeviceProfile文件如下函数中

 ArrayList getPredefinedDeviceProfiles(Context context) {
        ArrayList profiles = new ArrayList<>();
        try (XmlResourceParser parser = context.getResources().getXml(R.xml.device_profiles)) {
            final int depth = parser.getDepth();
            int type;

            while (((type = parser.next()) != XmlPullParser.END_TAG ||
                    parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) {
                if ((type == XmlPullParser.START_TAG) && "profile".equals(parser.getName())) {
                    TypedArray a = context.obtainStyledAttributes(
                            Xml.asAttributeSet(parser), R.styleable.InvariantDeviceProfile);
                    int numRows = a.getInt(R.styleable.InvariantDeviceProfile_numRows, 0);
                    int numColumns = a.getInt(R.styleable.InvariantDeviceProfile_numColumns, 0);
                    float iconSize = a.getFloat(R.styleable.InvariantDeviceProfile_iconSize, 0);
                    profiles.add(new InvariantDeviceProfile(
                            a.getString(R.styleable.InvariantDeviceProfile_name),
                            a.getFloat(R.styleable.InvariantDeviceProfile_minWidthDps, 0),
                            a.getFloat(R.styleable.InvariantDeviceProfile_minHeightDps, 0),
                            numRows,
                            numColumns,
                            a.getInt(R.styleable.InvariantDeviceProfile_numFolderRows, numRows),
                            a.getInt(R.styleable.InvariantDeviceProfile_numFolderColumns, numColumns),
                            a.getInt(R.styleable.InvariantDeviceProfile_minAllAppsPredictionColumns, numColumns),
                            iconSize,
                            a.getFloat(R.styleable.InvariantDeviceProfile_landscapeIconSize, iconSize),
                            a.getFloat(R.styleable.InvariantDeviceProfile_iconTextSize, 0),
                            a.getInt(R.styleable.InvariantDeviceProfile_numHotseatIcons, numColumns),
                            a.getResourceId(R.styleable.InvariantDeviceProfile_defaultLayoutId, 0),
                            a.getResourceId(R.styleable.InvariantDeviceProfile_demoModeLayoutId, 0)));
                    a.recycle();
                }
            }
        } catch (IOException|XmlPullParserException e) {
            throw new RuntimeException(e);
        }
        return profiles;
    }

它会首先去解析device_profiles.xml文件，获取相应的属性：如hotseta位置的数量是由 launcher:numHotseatIcons决定

Android O对应的解析文件：res/xml/device_profiles.xml 有多套不同的profile，代码中通过计算屏幕的最小宽度和高度，在device_profiles中查找到最接近的一个profile进行匹配设置！

        // This guarantees that width < height
        minWidthDps = Utilities.dpiFromPx(Math.min(smallestSize.x, smallestSize.y), dm);
        minHeightDps = Utilities.dpiFromPx(Math.min(largestSize.x, largestSize.y), dm);

        ArrayList closestProfiles = findClosestDeviceProfiles(
                minWidthDps, minHeightDps, getPredefinedDeviceProfiles(context));
        InvariantDeviceProfile interpolatedDeviceProfileOut =
                invDistWeightedInterpolate(minWidthDps,  minHeightDps, closestProfiles);

        InvariantDeviceProfile closestProfile = closestProfiles.get(0);
        numRows = closestProfile.numRows;
        numColumns = closestProfile.numColumns;
        numHotseatIcons = closestProfile.numHotseatIcons;
        defaultLayoutId = closestProfile.defaultLayoutId;
        demoModeLayoutId = closestProfile.demoModeLayoutId;
        numFolderRows = closestProfile.numFolderRows;
        numFolderColumns = closestProfile.numFolderColumns;
        minAllAppsPredictionColumns = closestProfile.minAllAppsPredictionColumns;

注：如何计算手机分辨率的最小宽度和高度？

例如：手机分辨率为720*1280，DPI=320。

竖屏时：X*Y=720*1230(1230=屏幕高度-状态栏高度-NavigationBar高度)

横屏时：Y*X=646*1280(646=屏幕宽度-状态栏高度-NavigationBar高度)

最小宽度为：323=Min(720,646)/(320/160)

最小高度为：615=Min(1230,1280)/(320/160)

Android Go对应的解析文件：go/res/xml/device_profiles.xml 只有固定的一个profile

 

2 Launcher3 如果桌面壁纸是单一颜色，AllApps和状态栏背景色会由于壁纸颜色单一而变成透明

   针对该问题，有客户会认为该问题是一个Bug；如果屏蔽Launcher3对于壁纸颜色的监听？

在 packages/apps/Launcher3/com/android/launcher3/dynamicui/WallpaperColorInfo.java 构造函数中去除

private WallpaperColorInfo(Context context) {

mWallpaperManager = WallpaperManagerCompat.getInstance(context);

- mWallpaperManager.addOnColorsChangedListener(this);

+ //mWallpaperManager.addOnColorsChangedListener(this);

mExtractionType = ColorExtractionAlgorithm.newInstance(context);

update(mWallpaperManager.getWallpaperColors(FLAG_SYSTEM));

}

 3  有的项目，在进入主屏幕设置后，导致导航栏看不清问题；见下图

                                                

在packages/apps/Launcher3/src/com/android/launcher3/SettingsActivity.java的onCreate函数中增加对于导航栏相关控制即可，如下所示：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
		 View decorView = getWindow().getDecorView();
         decorView.setSystemUiVisibility(View.NAVIGATION_BAR_TRANSLUCENT);	
	    getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
     //getWindow().setNavigationBarColor(Color.TRANSPARENT);
        if (savedInstanceState == null) {
            // Display the fragment as the main content.
			
            getFragmentManager().beginTransaction()
                    .replace(android.R.id.content, new LauncherSettingsFragment())
                    .commit();
        }
    }