之前我简单介绍过AdaptiveIcon的适配方式和实现原理，今天主要介绍下在Launcher中是如何实现切换图标形状的。
Launcher设置图标形状
先看下SettingsActivity.java中的菜单实现
Preference iconShapeOverride = findPreference(IconShapeOverride.KEY_PREFERENCE);
if (iconShapeOverride != null) {
if (IconShapeOverride.isSupported(getActivity())) {
IconShapeOverride.handlePreferenceUi((ListPreference) iconShapeOverride);
} else {
getPreferenceScreen().removePreference(iconShapeOverride);
}
}
由此可以看到isSupported方法是是否支持设置图标形状的判断条件。
public static boolean isSupported(Context context) {
///1.判断系统SDK 版本是否>=26
if (!Utilities.isAtLeastO()) {
return false;
}
// Only supported when developer settings is enabled
///2.是否打开了开发者选项。如果开发者选项没打开，就看不到这个菜单。
if (Settings.Global.getInt(context.getContentResolver(),
Settings.Global.DEVELOPMENT_SETTINGS_ENABLED, 0) != 1) {
return false;
}
try {
if (getSystemResField().get(null) != Resources.getSystem()) {
// Our assumption that mSystem is the system resource is not true.
/// 3.大概意思就是获取不到mSystem，如果获取不到，说明当前系统存在问题
return false;
}
} catch (Exception e) {
// Ignore, not supported
return false;
}
///4. 获取系统中config_icon_mask的resource id
return getConfigResId() != 0;
}
注意点就是android 8.0设备要打开开发者选项一般就会有此功能，说明支持AdaptiveIcon.
菜单出现后，我们选择其中一种形状来设置。
<!-- Values for icon shape overrides. These should correspond to entries defined
in icon_shape_override_paths_names -->
<string-array translatable="false" name="icon_shape_override_paths_values">
<item></item>
<item>M50,0L100,0 100,100 0,100 0,0z</item>
<item>M50,0 C10,0 0,10 0,50 0,90 10,100 50,100 90,100 100,90 100,50 100,10 90,0 50,0 Z</item>
<item>M50 0A50 50,0,1,1,50 100A50 50,0,1,1,50 0</item>
<item>M50,0A50,50,0,0 1 100,50 L100,85 A15,15,0,0 1 85,100 L50,100 A50,50,0,0 1 50,0z</item>
</string-array>
<string-array translatable="false" name="icon_shape_override_paths_names">
<!-- Option to not change the icon shape on home screen. [CHAR LIMIT=50] -->
<item>@string/icon_shape_system_default</item>
<item>Square</item>
<item>Squircle</item>
<item>Circle</item>
<item>Teardrop</item>
</string-array>
打开可以看到一个形状对应的value 就是一个矢量图的string值。
private static class PreferenceChangeHandler implements OnPreferenceChangeListener {
private final Context mContext;
private PreferenceChangeHandler(Context context) {
mContext = context;
}
@Override
public boolean onPreferenceChange(Preference preference, Object o) {
String newValue = (String) o;
if (!getAppliedValue(mContext).equals(newValue)) {
// Value has changed
ProgressDialog.show(mContext,
null /* title */,
mContext.getString(R.string.icon_shape_override_progress),
true /* indeterminate */,
false /* cancelable */);
new LooperExecuter(LauncherModel.getWorkerLooper()).execute(
new OverrideApplyHandler(mContext, newValue));
}
return false;
}
}
private static class OverrideApplyHandler implements Runnable {
private final Context mContext;
private final String mValue;
private OverrideApplyHandler(Context context, String value) {
mContext = context;
mValue = value;
}
@Override
public void run() {
// Synchronously write the preference.
prefs(mContext).edit().putString(KEY_PREFERENCE, mValue).commit();
// Clear the icon cache.
LauncherAppState.getInstance(mContext).getIconCache().clear();
// Wait for it
try {
Thread.sleep(PROCESS_KILL_DELAY_MS);
} catch (Exception e) {
Log.e(TAG, "Error waiting", e);
}
// Schedule an alarm before we kill ourself.
Intent homeIntent = new Intent(Intent.ACTION_MAIN)
.addCategory(Intent.CATEGORY_HOME)
.setPackage(mContext.getPackageName())
.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
PendingIntent pi = PendingIntent.getActivity(mContext, RESTART_REQUEST_CODE,
homeIntent, PendingIntent.FLAG_CANCEL_CURRENT | PendingIntent.FLAG_ONE_SHOT);
mContext.getSystemService(AlarmManager.class).setExact(
AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime() + 50, pi);
// Kill process
android.os.Process.killProcess(android.os.Process.myPid());
}
}
设置的时候执行上面代码，主要将设置的保存到本地，清除图标缓存，然后重启launcher。
如何改变Launcher上的图标的
我们再看下上面设置的图标形状的value到底是怎么使用的，如何使图标变化的
我们找到LauncherProvider 的onCreate方法里面使用的地方。
IconShapeOverride.apply(getContext());
看看这个apply方法：
private static int getConfigResId() {
return Resources.getSystem().getIdentifier("config_icon_mask", "string", "android");
}
public static void apply(Context context) {
if (!Utilities.isAtLeastO()) {
return;
}
String path = getAppliedValue(context);
if (TextUtils.isEmpty(path)) {
return;
}
if (!isSupported(context)) {
return;
}
// magic
try {
Resources override =
new ResourcesOverride(Resources.getSystem(), getConfigResId(), path);
getSystemResField().set(null, override);
} catch (Exception e) {
Log.e(TAG, "Unable to override icon shape", e);
// revert value.
prefs(context).edit().remove(KEY_PREFERENCE).apply();
}
}
其中ResourcesOverride是继承了Resources，并且重写了getString方法
private static class ResourcesOverride extends Resources {
private final int mOverrideId;
private final String mOverrideValue;
@SuppressWarnings("deprecated")
public ResourcesOverride(Resources parent, int overrideId, String overrideValue) {
super(parent.getAssets(), parent.getDisplayMetrics(), parent.getConfiguration());
mOverrideId = overrideId;
mOverrideValue = overrideValue;
}
@NonNull
@Override
public String getString(int id) throws NotFoundException {
if (id == mOverrideId) {
return mOverrideValue;
}
return super.getString(id);
}
}
再看一下getSystemResField方法
private static Field getSystemResField() throws Exception {
Field staticField = Resources.class.getDeclaredField("mSystem");
staticField.setAccessible(true);
return staticField;
}
这个方法是反射系统Resources中mSystem变量。
上面大概的意思就是Launcher中将Resources 的mSystem设置成了ResourcesOverride对象，
也就是说Resources的getSystem方法获取的是我们重写的ResourcesOverride，当调用getString方法的时候，走的也是重写的方法。getString方法里面判断了如果string id 是config_icon_mask这个的时候，返回我们传入的mOverrideValue，这个mOverrideValue就是用户选择的图标形状值。
/**
* Return a global shared Resources object that provides access to only
* system resources (no application resources), and is not configured for
* the current screen (can not use dimension units, does not change based
* on orientation, etc).
*/
public static Resources getSystem() {
synchronized (sSync) {
Resources ret = mSystem;
if (ret == null) {
ret = new Resources();
mSystem = ret;
}
return ret;
}
}
现在回头看下AdaptiveIconDrawable的构造方法：
/**
* The one constructor to rule them all. This is called by all public
* constructors to set the state and initialize local properties.
*/
AdaptiveIconDrawable(@Nullable LayerState state, @Nullable Resources res) {
mLayerState = createConstantState(state, res);
if (sMask == null) {
sMask = PathParser.createPathFromPathData(
Resources.getSystem().getString(R.string.config_icon_mask));
}
mMask = PathParser.createPathFromPathData(
Resources.getSystem().getString(R.string.config_icon_mask));
mMaskMatrix = new Matrix();
mCanvas = new Canvas();
mTransparentRegion = new Region();
}
此方法的Resources.getSystem().getString(R.string.config_icon_mask)，通过getString方法，如果id是config_icon_mask，则返回的是mOverrideValue，mOverrideValue就是上面5种里面的一种。
因此，Launcher获取应用图标的时候时候，如果该应用是支持AdaptiveIcon的话，返回的图标就是根据形状裁剪出来的AdaptiveIconDrawable，Launcher从系统拿到的图标已经是想要的形状图标了。
看下我们Launcher是如何获取应用图标的
public Drawable getFullResIcon(LauncherActivityInfo info) {
return mIconProvider.getIcon(info, mIconDpi);
}
public Drawable getIcon(LauncherActivityInfo info, int iconDpi) {
return info.getIcon(iconDpi);
}
最终调用到LauncherActivityInfo的getIcon方法
/**
* Returns the icon for this activity, without any badging for the profile.
* @param density The preferred density of the icon, zero for default density. Use
* density DPI values from {@link DisplayMetrics}.
* @see #getBadgedIcon(int)
* @see DisplayMetrics
* @return The drawable associated with the activity.
*/
public Drawable getIcon(int density) {
// TODO: Go through LauncherAppsService
final int iconRes = mActivityInfo.getIconResource();
Drawable icon = null;
// Get the preferred density icon from the app's resources
if (density != 0 && iconRes != 0) {
try {
final Resources resources
= mPm.getResourcesForApplication(mActivityInfo.applicationInfo);
icon = resources.getDrawableForDensity(iconRes, density);
} catch (NameNotFoundException | Resources.NotFoundException exc) {
}
}
// Get the default density icon
if (icon == null) {
icon = mActivityInfo.loadIcon(mPm);
}
return icon;
}
经过试验，系统返回的drawable，就已经是我们想要的设置的形状图标了。
Demo验证
下面我自己参考上述的代码，写个独立的demo，看看获取的图标。我们可以传任意形状的图形，看看返回的图显示情况。
我们将上面的写在一个helper类中。代码如下：
/**
* Created by LeongAndroid on 2017/11/9.
*/
@TargetApi(Build.VERSION_CODES.O)
public class IconShapeOverrideHelper {
/**
* 设置应用的新Resource
* @param path
*/
public static void apply(String path) {
try {
Resources override =
new ResourcesOverride(Resources.getSystem(), getConfigResId(), path);
getSystemResField().set(null, override);
} catch (Exception e) {
// revert value.
Log.d("IconShapeHelper", "apply exception "+e);
}
}
private static Field getSystemResField() throws Exception {
Field staticField = Resources.class.getDeclaredField("mSystem");
staticField.setAccessible(true);
return staticField;
}
private static int getConfigResId() {
return Resources.getSystem().getIdentifier("config_icon_mask", "string", "android");
}
private static class ResourcesOverride extends Resources {
private final int mOverrideId;
private final String mOverrideValue;
@SuppressWarnings("deprecated")
public ResourcesOverride(Resources parent, int overrideId, String overrideValue) {
super(parent.getAssets(), parent.getDisplayMetrics(), parent.getConfiguration());
mOverrideId = overrideId;
mOverrideValue = overrideValue;
}
@NonNull
@Override
public String getString(int id) throws NotFoundException {
if (id == mOverrideId) {
return mOverrideValue;
}
return super.getString(id);
}
}
public static Drawable getAppIcon(PackageManager pm, String packname){
try {
ApplicationInfo info = pm.getApplicationInfo(packname, 0);
return info.loadIcon(pm);
} catch (PackageManager.NameNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/**
* 此方法可以获取应用图标的原始图
* @param mPackageManager
* @param packageName
* @return
*/
public static Bitmap getAppIcon2(PackageManager mPackageManager, String packageName) {
try {
Drawable drawable = mPackageManager.getApplicationIcon(packageName);
if (drawable instanceof BitmapDrawable) {
return ((BitmapDrawable) drawable).getBitmap();
} else if (drawable instanceof AdaptiveIconDrawable) {
Drawable backgroundDr = ((AdaptiveIconDrawable) drawable).getBackground();
Drawable foregroundDr = ((AdaptiveIconDrawable) drawable).getForeground();
Drawable[] drr = new Drawable[2];
drr[0] = backgroundDr;
drr[1] = foregroundDr;
LayerDrawable layerDrawable = new LayerDrawable(drr);
int width = layerDrawable.getIntrinsicWidth();
int height = layerDrawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
layerDrawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
layerDrawable.draw(canvas);
return bitmap;
}
} catch (PackageManager.NameNotFoundException e) {
e.printStackTrace();
}
return null;
}
}
然后再写个Activity，通过标准api来获取应用图标，看看显示什么。
public class AdaptiveIconActivity extends AppCompatActivity {
private static final String TAG = "AdaptiveIcon";
private ImageView imageView = null;
private ImageView imageView1 = null;
String patch = "M50,0A50,50,0,0 1 100,50 L100,85 A15,15,0,0 1 85,100 L50,100 A50,50,0,0 1 50,0z";
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.adaptive_icon_layout);
IconShapeOverrideHelper.apply(patch);
imageView = (ImageView)this.findViewById(R.id.image);
imageView1 = (ImageView)this.findViewById(R.id.image1);
///直接用标准接口获取图标
Drawable drawable = IconShapeOverrideHelper.getAppIcon(getPackageManager(), "com.leong.testandroido");
imageView.setImageDrawable(drawable);
///图标原始
Bitmap bitmap = IconShapeOverrideHelper.getAppIcon2(getPackageManager(), "com.leong.testandroido");
Log.d(TAG, "origin bitmap w = "+bitmap.getWidth()+", h = "+bitmap.getHeight());
imageView1.setImageBitmap(bitmap);
}
}
显示效果如下：
效果图
上面的图就是我们返回的图标，下面的图是一个应用的原图。
Demo 源码路径：https://github.com/LeongAndroid/OLauncherNewFeature
总结
上面的方式我们可以设想下，如果Launcher3 将设置的图标形状这个参数公开出去，那所有其他的应用都可以根据这个mMask来获取跟Launcher3相同形状的图标。当然，这个就需要修改下Launcher3的代码了，将设置的参数公开给外部应用。
由于作者本人能力有限，如果文中有错误的地方，欢迎指正，十分感谢啊！！
