上一章墨香帶你學(xué)Launcher之（七）- 小部件的加載、添加以及大小調(diào)節(jié)介紹了小部件的加載以及添加過程熟尉，基于我的計(jì)劃對(duì)于Launcher的講解基本要完成了，因此本篇是我對(duì)Launcher講解的最后一部分洲脂，計(jì)劃了很久斤儿，因?yàn)闀r(shí)間的問題一直沒有寫剧包，今天趁著有空寫完。寫了八篇往果，不多疆液，Launcher里面還有很多東西，有興趣的可以自己繼續(xù)研究陕贮，看完這些主要的其他都是問題了堕油，有什么需要了解的可以留言。最新版的Launcher代碼我已經(jīng)放到github上肮之，想看的自己可以去下載掉缺。
加載Icon
對(duì)于Icon的操作其實(shí)主要是加載、更新以及刪除戈擒，加載主要是啟動(dòng)Launcher眶明、安裝應(yīng)用，更新是在更新應(yīng)用時(shí)更新Icon峦甩、刪除是卸載應(yīng)用時(shí)會(huì)刪除Icon赘来，因此我們可以從這幾方面分析Icon的處理。
Launcher啟動(dòng)時(shí)Icon加載
Launcher的數(shù)據(jù)加載流程我在第二篇墨香帶你學(xué)Launcher之（二）- 數(shù)據(jù)加載流程講過,不熟悉的可以去看看凯傲。首先是將xml文件中配置的Apk信息解析保存到數(shù)據(jù)庫犬辰，然后讀取數(shù)據(jù)庫，查看手機(jī)中是否存在該apk冰单，如果有加載相關(guān)信息幌缝，加載流程在“l(fā)oadWorkspace”方法中，在加載過程中會(huì)去生成對(duì)應(yīng)的Icon诫欠，我們看一下代碼：
if (itemReplaced) {
...
info = getAppShortcutInfo(manager, intent, user, context, null,
cursorIconInfo.iconIndex, titleIndex,
false, useLowResIcon);
...
} else if (restored) {
...
info = getRestoredItemInfo(c, titleIndex, intent,
promiseType, itemType, cursorIconInfo, context);
...
} else if (itemType == LauncherSettings.Favorites.ITEM_TYPE_APPLICATION) {
info = getAppShortcutInfo(manager, intent, user, context, c,
cursorIconInfo.iconIndex, titleIndex,
allowMissingTarget, useLowResIcon);
} else {
info = getShortcutInfo(c, context, titleIndex, cursorIconInfo);
...
}
在段代碼中主要有三個(gè)方法涉及到加載Icon涵卵，getAppShortcutInfo、getRestoredItemInfo以及getShortcutInfo方法荒叼，我們看看這個(gè)三個(gè)方法的代碼：
第一個(gè)：
public ShortcutInfo getAppShortcutInfo(PackageManager manager, Intent intent,
UserHandleCompat user, Context context, Cursor c, int iconIndex, int titleIndex,
boolean allowMissingTarget, boolean useLowResIcon) {
...
final ShortcutInfo info = new ShortcutInfo();
mIconCache.getTitleAndIcon(info, componentName, lai, user, false, useLowResIcon);
if (mIconCache.isDefaultIcon(info.getIcon(mIconCache), user) && c != null) {
Bitmap icon = Utilities.createIconBitmap(c, iconIndex, context);
info.setIcon(icon == null ? mIconCache.getDefaultIcon(user) : icon);
}
...
}
在這段代碼中主要是調(diào)用IconCache中的getTitleAndIcon方法轿偎，這個(gè)方法詳細(xì)過程我們一會(huì)再看，然后判斷是否是默認(rèn)圖標(biāo)被廓，如果是生成Icon圖標(biāo)坏晦，如果能生成則設(shè)置圖標(biāo)，如果不能生成則采用默認(rèn)圖標(biāo)嫁乘。Utilities.createIconBitmap代碼不在詳細(xì)講昆婿，看看就會(huì)了。
我們接著看第二個(gè)方法：
public ShortcutInfo getRestoredItemInfo(Cursor c, int titleIndex, Intent intent,
int promiseType, int itemType, CursorIconInfo iconInfo, Context context) {
...
Bitmap icon = iconInfo.loadIcon(c, info, context);
// the fallback icon
if (icon == null) {
mIconCache.getTitleAndIcon(info, intent, info.user, false /* useLowResIcon */);
} else {
info.setIcon(icon);
}
...
}
這個(gè)方法中主要是調(diào)用CursorIconInfo中的loadIcon方法蜓斧，代碼我們一會(huì)再看仓蛆，如果能獲取到Icon則設(shè)置這個(gè)Icon，如果不能則通過IconCache.getTitleAndIcon方法獲取挎春，和上面一樣了看疙。
第三個(gè)方法：
ShortcutInfo getShortcutInfo(Cursor c, Context context,
int titleIndex, CursorIconInfo iconInfo) {
...
Bitmap icon = iconInfo.loadIcon(c, info, context);
// the fallback icon
if (icon == null) {
icon = mIconCache.getDefaultIcon(info.user);
info.usingFallbackIcon = true;
}
info.setIcon(icon);
return info;
}
這個(gè)方法中還是調(diào)用CursorIconInfo中的loadIcon方法豆拨，如果能獲取，則設(shè)置圖標(biāo)能庆，如果不能獲取默認(rèn)圖標(biāo)設(shè)置辽装。從上面三個(gè)方法代碼看其實(shí)最終調(diào)用了兩個(gè)方法，一個(gè)是IconCache.getTitleAndIcon方法相味，一個(gè)是CursorIconInfo.loadIcon方法。
我們先看一下CursorIconInfo.loadIcon代碼：
public Bitmap loadIcon(Cursor c, ShortcutInfo info, Context context) {
Bitmap icon = null;
int iconType = c.getInt(iconTypeIndex);
switch (iconType) {
case LauncherSettings.Favorites.ICON_TYPE_RESOURCE:
String packageName = c.getString(iconPackageIndex);
String resourceName = c.getString(iconResourceIndex);
if (!TextUtils.isEmpty(packageName) || !TextUtils.isEmpty(resourceName)) {
info.iconResource = new ShortcutIconResource();
info.iconResource.packageName = packageName;
info.iconResource.resourceName = resourceName;
icon = Utilities.createIconBitmap(packageName, resourceName, context);
}
if (icon == null) {
// Failed to load from resource, try loading from DB.
icon = Utilities.createIconBitmap(c, iconIndex, context);
}
break;
case LauncherSettings.Favorites.ICON_TYPE_BITMAP:
icon = Utilities.createIconBitmap(c, iconIndex, context);
info.customIcon = icon != null;
break;
}
return icon;
}
在這個(gè)方法中首先是從資源獲取殉挽，如果獲取不到丰涉，則從數(shù)據(jù)庫獲取，及Utilities.createIconBitmap(packageName, resourceName, context)和Utilities.createIconBitmap(c, iconIndex, context)斯碌，我們看看這兩個(gè)方法：
第一個(gè)方法：
public static Bitmap createIconBitmap(String packageName, String resourceName,
Context context) {
PackageManager packageManager = context.getPackageManager();
// the resource
try {
Resources resources = packageManager.getResourcesForApplication(packageName);
if (resources != null) {
final int id = resources.getIdentifier(resourceName, null, null);
return createIconBitmap(
resources.getDrawableForDensity(id, LauncherAppState.getInstance()
.getInvariantDeviceProfile().fillResIconDpi), context);
}
} catch (Exception e) {
// Icon not found.
}
return null;
}
這個(gè)方法是根據(jù)包名獲取id一死，然后根據(jù)id獲取drawable，由drawable生產(chǎn)Bitmap傻唾。
第二個(gè)方法：
public static Bitmap createIconBitmap(Cursor c, int iconIndex, Context context) {
byte[] data = c.getBlob(iconIndex);
try {
return createIconBitmap(BitmapFactory.decodeByteArray(data, 0, data.length), context);
} catch (Exception e) {
return null;
}
}
從數(shù)據(jù)庫讀取Icon的byte數(shù)據(jù)投慈，然后生成圖片。這樣看就很清楚這個(gè)方法加載Icon的過程了冠骄。那么數(shù)據(jù)庫中的Icon怎么來的我們回到前面再看IconCache.getTitleAndIcon方法：
public synchronized void getTitleAndIcon(
ShortcutInfo shortcutInfo, ComponentName component, LauncherActivityInfoCompat info,
UserHandleCompat user, boolean usePkgIcon, boolean useLowResIcon) {
CacheEntry entry = cacheLocked(component, info, user, usePkgIcon, useLowResIcon);
shortcutInfo.setIcon(getNonNullIcon(entry, user));
shortcutInfo.title = Utilities.trim(entry.title);
shortcutInfo.usingFallbackIcon = isDefaultIcon(entry.icon, user);
shortcutInfo.usingLowResIcon = entry.isLowResIcon;
}
我們看到了setIcon方法伪煤，那么是getNonNullIcon這個(gè)方法創(chuàng)建了Icon，這個(gè)方法有個(gè)我們不熟悉的對(duì)象entry凛辣，向上看這個(gè)entry是子啊上面通過cacheLocked方法創(chuàng)建的抱既，我們跟蹤一下這個(gè)方法：
private CacheEntry cacheLocked(ComponentName componentName, LauncherActivityInfoCompat info,
UserHandleCompat user, boolean usePackageIcon, boolean useLowResIcon) {
ComponentKey cacheKey = new ComponentKey(componentName, user);
CacheEntry entry = mCache.get(cacheKey);
if (entry == null || (entry.isLowResIcon && !useLowResIcon)) {
entry = new CacheEntry();
mCache.put(cacheKey, entry);
// Check the DB first.
if (!getEntryFromDB(cacheKey, entry, useLowResIcon)) {
if (info != null) {
entry.icon = Utilities.createIconBitmap(info.getBadgedIcon(mIconDpi), mContext);
} else {
if (usePackageIcon) {
CacheEntry packageEntry = getEntryForPackageLocked(
componentName.getPackageName(), user, false);
if (packageEntry != null) {
if (DEBUG) Log.d(TAG, "using package default icon for " +
componentName.toShortString());
entry.icon = packageEntry.icon;
entry.title = packageEntry.title;
entry.contentDescription = packageEntry.contentDescription;
}
}
if (entry.icon == null) {
entry.icon = getDefaultIcon(user);
}
}
}
...
}
return entry;
}
首先是從mCache中獲取，如果存在CacheEntry對(duì)象扁誓，則不需要再創(chuàng)建防泵，如果沒有則要?jiǎng)?chuàng)建改對(duì)象，然后加載到mCache中蝗敢，然后通過調(diào)用getEntryFromDB方法從數(shù)據(jù)庫查詢是否有改對(duì)象信息捷泞，如果沒有則要?jiǎng)?chuàng)建對(duì)應(yīng)Icon，我們先看看getEntryFromDB這個(gè)方法：
private boolean getEntryFromDB(ComponentKey cacheKey, CacheEntry entry, boolean lowRes) {
...
try {
if (c.moveToNext()) {
entry.icon = loadIconNoResize(c, 0, lowRes ? mLowResOptions : null);
entry.isLowResIcon = lowRes;
...
}
} finally {
c.close();
}
return false;
}
該方法通過查詢數(shù)據(jù)庫來生成Icon寿谴，調(diào)用方法loadIconNoResize锁右，看代碼：
private static Bitmap loadIconNoResize(Cursor c, int iconIndex, BitmapFactory.Options options) {
byte[] data = c.getBlob(iconIndex);
try {
return BitmapFactory.decodeByteArray(data, 0, data.length, options);
} catch (Exception e) {
return null;
}
}
和上面的一樣，就不用講了拭卿。
回到cacheLocked方法中骡湖，如果數(shù)據(jù)庫中沒有，要繼續(xù)創(chuàng)建Icon峻厚，首先判斷LauncherActivityInfoCompat是否為空响蕴，調(diào)用Utilities.createIconBitmap方法獲取Icon，代碼就不貼了惠桃，也不難浦夷，如果為空的話會(huì)判斷usePackageIcon（根據(jù)包名獲取Icon）辖试，如果用的話則會(huì)調(diào)用getEntryForPackageLocked方法獲取CacheEntry，看代碼：
private CacheEntry getEntryForPackageLocked(String packageName, UserHandleCompat user,
boolean useLowResIcon) {
ComponentKey cacheKey = getPackageKey(packageName, user);
CacheEntry entry = mCache.get(cacheKey);
if (entry == null || (entry.isLowResIcon && !useLowResIcon)) {
entry = new CacheEntry();
boolean entryUpdated = true;
// Check the DB first.
if (!getEntryFromDB(cacheKey, entry, useLowResIcon)) {
try {
...
Drawable drawable = mUserManager.getBadgedDrawableForUser(
appInfo.loadIcon(mPackageManager), user);
entry.icon = Utilities.createIconBitmap(drawable, mContext);
entry.title = appInfo.loadLabel(mPackageManager);
entry.contentDescription = mUserManager.getBadgedLabelForUser(entry.title, user);
entry.isLowResIcon = false;
// Add the icon in the DB here, since these do not get written during
// package updates.
ContentValues values =
newContentValues(entry.icon, entry.title.toString(), mPackageBgColor);
addIconToDB(values, cacheKey.componentName, info,
mUserManager.getSerialNumberForUser(user));
} catch (NameNotFoundException e) {
if (DEBUG) Log.d(TAG, "Application not installed " + packageName);
entryUpdated = false;
}
}
// Only add a filled-out entry to the cache
if (entryUpdated) {
mCache.put(cacheKey, entry);
}
}
return entry;
}
代碼和cacheLocked方法很像劈狐，也是先判斷數(shù)據(jù)庫中是否存在罐孝，不存在就要加載，這里有個(gè)方法addIconToDB肥缔，看上面ContentValues的注釋莲兢，就是把Icon存到數(shù)據(jù)庫中，原來是在這里存入數(shù)據(jù)庫的续膳，其實(shí)Icon的信息首先放入ContentValues中改艇，然后存入數(shù)據(jù)庫，我們看看代碼：
private ContentValues newContentValues(Bitmap icon, String label, int lowResBackgroundColor) {
ContentValues values = new ContentValues();
values.put(IconDB.COLUMN_ICON, Utilities.flattenBitmap(icon));
values.put(IconDB.COLUMN_LABEL, label);
values.put(IconDB.COLUMN_SYSTEM_STATE, mSystemState);
if (lowResBackgroundColor == Color.TRANSPARENT) {
values.put(IconDB.COLUMN_ICON_LOW_RES, Utilities.flattenBitmap(
Bitmap.createScaledBitmap(icon,
icon.getWidth() / LOW_RES_SCALE_FACTOR,
icon.getHeight() / LOW_RES_SCALE_FACTOR, true)));
} else {
synchronized (this) {
if (mLowResBitmap == null) {
mLowResBitmap = Bitmap.createBitmap(icon.getWidth() / LOW_RES_SCALE_FACTOR,
icon.getHeight() / LOW_RES_SCALE_FACTOR, Bitmap.Config.RGB_565);
mLowResCanvas = new Canvas(mLowResBitmap);
mLowResPaint = new Paint(Paint.FILTER_BITMAP_FLAG | Paint.ANTI_ALIAS_FLAG);
}
mLowResCanvas.drawColor(lowResBackgroundColor);
mLowResCanvas.drawBitmap(icon, new Rect(0, 0, icon.getWidth(), icon.getHeight()),
new Rect(0, 0, mLowResBitmap.getWidth(), mLowResBitmap.getHeight()),
mLowResPaint);
values.put(IconDB.COLUMN_ICON_LOW_RES, Utilities.flattenBitmap(mLowResBitmap));
}
}
return values;
}
通過Utilities.flattenBitmap(icon)方法將Icon轉(zhuǎn)換成byte數(shù)組然后存入數(shù)據(jù)庫坟岔。再回到cacheLocked方法中谒兄，如果還是沒有獲取到Icon，那么只能獲取系統(tǒng)默認(rèn)Icon了社付，也就是我們自己寫app的默認(rèn)Icon圖標(biāo)（機(jī)器人圖標(biāo)）承疲。這個(gè)是我們加載配置文件中的Apk信息時(shí)加載Icon的過程荠卷，我們?cè)倏纯醇虞d所有app時(shí)是不是也是這樣肴盏，我們先看加載方法loadAllApps代碼：
private void loadAllApps() {
...
// Create the ApplicationInfos
for (int i = 0; i < apps.size(); i++) {
LauncherActivityInfoCompat app = apps.get(i);
// This builds the icon bitmaps.
mBgAllAppsList.add(new AppInfo(mContext, app, user, mIconCache));
}
...
}
我們看到主要是AppInfo對(duì)象的生成，我們看看代碼：
public AppInfo(Context context, LauncherActivityInfoCompat info, UserHandleCompat user,
IconCache iconCache) {
this.componentName = info.getComponentName();
this.container = ItemInfo.NO_ID;
flags = initFlags(info);
firstInstallTime = info.getFirstInstallTime();
iconCache.getTitleAndIcon(this, info, true /* useLowResIcon */);
intent = makeLaunchIntent(context, info, user);
this.user = user;
}
從上面代碼我們看到其實(shí)還是調(diào)用getTitleAndIcon方法敬拓，又回到我們上面講的過程了扛或。
APK安裝绵咱、更新、卸載時(shí)Icon處理
APK的安裝熙兔、卸載悲伶、更新、可用以及不可用在墨香帶你學(xué)Launcher之（四）-應(yīng)用安裝住涉、更新麸锉、卸載時(shí)的數(shù)據(jù)加載中講到過，不清楚的可以去看看舆声，這幾個(gè)實(shí)現(xiàn)方法是在LauncherModel中來處理的：
@Override
public void onPackageChanged(String packageName, UserHandleCompat user) {
int op = PackageUpdatedTask.OP_UPDATE;
enqueuePackageUpdated(new PackageUpdatedTask(op, new String[]{packageName},
user));
}
@Override
public void onPackageRemoved(String packageName, UserHandleCompat user) {
int op = PackageUpdatedTask.OP_REMOVE;
enqueuePackageUpdated(new PackageUpdatedTask(op, new String[]{packageName},
user));
}
@Override
public void onPackageAdded(String packageName, UserHandleCompat user) {
int op = PackageUpdatedTask.OP_ADD;
enqueuePackageUpdated(new PackageUpdatedTask(op, new String[]{packageName},
user));
}
@Override
public void onPackagesAvailable(String[] packageNames, UserHandleCompat user,
boolean replacing) {
if (!replacing) {
enqueuePackageUpdated(new PackageUpdatedTask(PackageUpdatedTask.OP_ADD, packageNames,
user));
if (mAppsCanBeOnRemoveableStorage) {
startLoaderFromBackground();
}
} else {
// If we are replacing then just update the packages in the list
enqueuePackageUpdated(new PackageUpdatedTask(PackageUpdatedTask.OP_UPDATE,
packageNames, user));
}
}
@Override
public void onPackagesUnavailable(String[] packageNames, UserHandleCompat user,
boolean replacing) {
if (!replacing) {
enqueuePackageUpdated(new PackageUpdatedTask(
PackageUpdatedTask.OP_UNAVAILABLE, packageNames,
user));
}
}
我們看代碼發(fā)現(xiàn)其實(shí)都是PackageUpdatedTask這個(gè)執(zhí)行方法花沉，代碼比較多，我們只貼重點(diǎn)部分媳握，詳細(xì)的可以去看源碼：
private class PackageUpdatedTask implements Runnable {
...
public void run() {
...
switch (mOp) {
case OP_ADD: {
for (int i = 0; i < N; i++) {
...
mIconCache.updateIconsForPkg(packages[i], mUser);
...
}
...
break;
}
case OP_UPDATE:
for (int i = 0; i < N; i++) {
...
mIconCache.updateIconsForPkg(packages[i], mUser);
...
}
break;
case OP_REMOVE: {
...
for (int i = 0; i < N; i++) {
...
mIconCache.removeIconsForPkg(packages[i], mUser);
}
}
case OP_UNAVAILABLE:
for (int i = 0; i < N; i++) {
...
}
break;
}
...
// Update shortcut infos
if (mOp == OP_ADD || mOp == OP_UPDATE) {
...
synchronized (sBgLock) {
for (ItemInfo info : sBgItemsIdMap) {
if (info instanceof ShortcutInfo && mUser.equals(info.user)) {
...
// Update shortcuts which use iconResource.
if ((si.iconResource != null)
&& packageSet.contains(si.iconResource.packageName)) {
Bitmap icon = Utilities.createIconBitmap(
si.iconResource.packageName,
si.iconResource.resourceName, context);
if (icon != null) {
si.setIcon(icon);
...
}
}
ComponentName cn = si.getTargetComponent();
if (cn != null && packageSet.contains(cn.getPackageName())) {
...
if (si.isPromise()) {
...
si.updateIcon(mIconCache);
}
if (appInfo != null && Intent.ACTION_MAIN.equals(si.intent.getAction())
&& si.itemType == LauncherSettings.Favorites.ITEM_TYPE_APPLICATION) {
si.updateIcon(mIconCache);
...
}
...
}
...
}
}
}
}
}
}
在上面代碼中我們看到OP_ADD（安裝）碱屁、OP_UPDATE（更新）時(shí)都是調(diào)用的mIconCache.removeIconsForPkg，而和OP_REMOVE（卸載）時(shí)調(diào)用mIconCache.removeIconsForPkg方法蛾找，而在下面又調(diào)用了si.setIcon(icon)娩脾、si.updateIcon來更新Icon，我們分別來看看這四個(gè)方法打毛，首先看第一個(gè)方法（removeIconsForPkg）：
public synchronized void updateIconsForPkg(String packageName, UserHandleCompat user) {
removeIconsForPkg(packageName, user);
try {
PackageInfo info = mPackageManager.getPackageInfo(packageName,
PackageManager.GET_UNINSTALLED_PACKAGES);
long userSerial = mUserManager.getSerialNumberForUser(user);
for (LauncherActivityInfoCompat app : mLauncherApps.getActivityList(packageName, user)) {
addIconToDBAndMemCache(app, info, userSerial);
}
} catch (NameNotFoundException e) {
Log.d(TAG, "Package not found", e);
return;
}
}
首先調(diào)用removeIconsForPkg方法柿赊，也就是刪除Icon俩功，看代碼：
public synchronized void removeIconsForPkg(String packageName, UserHandleCompat user) {
removeFromMemCacheLocked(packageName, user);
long userSerial = mUserManager.getSerialNumberForUser(user);
mIconDb.getWritableDatabase().delete(IconDB.TABLE_NAME,
IconDB.COLUMN_COMPONENT + " LIKE ? AND " + IconDB.COLUMN_USER + " = ?",
new String[] {packageName + "/%", Long.toString(userSerial)});
}
首先調(diào)用removeFromMemCacheLocked方法，其實(shí)這個(gè)方法就是從mCache中把緩存的CacheEntry對(duì)象刪除碰声，然后再從數(shù)據(jù)庫刪除Icon诡蜓。然后回到updateIconsForPkg方法，接著調(diào)用addIconToDBAndMemCache方法胰挑，也就是添加Icon到數(shù)據(jù)庫：
@Thunk void addIconToDBAndMemCache(LauncherActivityInfoCompat app, PackageInfo info,
long userSerial) {
// Reuse the existing entry if it already exists in the DB. This ensures that we do not
// create bitmap if it was already created during loader.
ContentValues values = updateCacheAndGetContentValues(app, false);
addIconToDB(values, app.getComponentName(), info, userSerial);
}
首先調(diào)用updateCacherAndGetContentValues這個(gè)方法：
@Thunk ContentValues updateCacheAndGetContentValues(LauncherActivityInfoCompat app,
boolean replaceExisting) {
final ComponentKey key = new ComponentKey(app.getComponentName(), app.getUser());
CacheEntry entry = null;
if (!replaceExisting) {
entry = mCache.get(key);
// We can't reuse the entry if the high-res icon is not present.
if (entry == null || entry.isLowResIcon || entry.icon == null) {
entry = null;
}
}
if (entry == null) {
entry = new CacheEntry();
entry.icon = Utilities.createIconBitmap(app.getBadgedIcon(mIconDpi), mContext);
}
entry.title = app.getLabel();
entry.contentDescription = mUserManager.getBadgedLabelForUser(entry.title, app.getUser());
mCache.put(new ComponentKey(app.getComponentName(), app.getUser()), entry);
return newContentValues(entry.icon, entry.title.toString(), mActivityBgColor);
}
這個(gè)方法是生成新的CacheEntry蔓罚，以及Icon，放將其放置到mCache中緩存瞻颂，就是我們上面刪除的那個(gè)脚粟，然后通過調(diào)用newContentValues方法將Icon轉(zhuǎn)換成byte數(shù)組放到ContentValues中，最后存入數(shù)據(jù)庫中蘸朋。這就是我們安裝，更新扣唱，卸載時(shí)對(duì)于Icon的數(shù)據(jù)庫操作藕坯。我們?cè)贗con生成后其實(shí)要放到相應(yīng)的應(yīng)用對(duì)象中，以方便我們顯示到桌面上噪沙，其實(shí)就是（setIcon(icon)炼彪、si.updateIcon（mIconCache））這兩個(gè)方法，第一個(gè)是直接將生成好的Icon放入到ShortcutInfo中正歼，另一個(gè)是從緩存獲取辐马，我們來看從緩存獲取這個(gè)方法：
public void updateIcon(IconCache iconCache) {
updateIcon(iconCache, shouldUseLowResIcon());
}
調(diào)用updateIcon方法：
public void updateIcon(IconCache iconCache, boolean useLowRes) {
if (itemType == LauncherSettings.Favorites.ITEM_TYPE_APPLICATION) {
iconCache.getTitleAndIcon(this, promisedIntent != null ? promisedIntent : intent, user,
useLowRes);
}
}
我們看到此時(shí)調(diào)用了iconCache.getTitleAndIcon方法，也就是又回到我們之前將的獲取Icon的方法了局义。
整個(gè)Icon加載的流程基本就是這些喜爷，有些我沒有詳細(xì)講解，自己看看就好了萄唇，Icon會(huì)放到ShortcutInfo中檩帐，在綁定圖標(biāo)的時(shí)候會(huì)讀取出來顯示到桌面上，流程就是這樣的另萤，如果要做切換主題其實(shí)就是從這里入手湃密。
設(shè)置壁紙
原生桌面長(zhǎng)按桌面空白處，會(huì)出現(xiàn)壁紙四敞、widget和設(shè)置三個(gè)菜單泛源，我們點(diǎn)擊壁紙會(huì)進(jìn)入壁紙選擇設(shè)置界面，也就是WallpaperPickerActivity忿危，WallpaperPickerActivity繼承WallpaperCropActivity达箍，所以有些操作可能分別在這兩個(gè)類中進(jìn)行。
設(shè)置壁紙是從WallpaperCropActivity中的setWallpaper方法開始的：
protected void setWallpaper(Uri uri, final boolean finishActivityWhenDone) {
int rotation = BitmapUtils.getRotationFromExif(getContext(), uri);
BitmapCropTask cropTask = new BitmapCropTask(
getContext(), uri, null, rotation, 0, 0, true, false, null);
final Point bounds = cropTask.getImageBounds();
Runnable onEndCrop = new Runnable() {
public void run() {
updateWallpaperDimensions(bounds.x, bounds.y);
if (finishActivityWhenDone) {
setResult(Activity.RESULT_OK);
finish();
}
}
};
cropTask.setOnEndRunnable(onEndCrop);
cropTask.setNoCrop(true);
cropTask.execute();
}
其中BitmapCropTask是一個(gè)異步任務(wù)癌蚁，也就是執(zhí)行異步任務(wù)設(shè)置壁紙然后調(diào)用onEndCrop中的run方法結(jié)束改界面幻梯，返回桌面兜畸。異步任務(wù)執(zhí)行順序是：onPreExecute-->doInBackground-->onPostExecute。我們看代碼：
public class BitmapCropTask extends AsyncTask<Void, Void, Boolean> {
// Helper to setup input stream
private InputStream regenerateInputStream() {
...
}
public boolean cropBitmap() {
...
}
@Override
protected Boolean doInBackground(Void... params) {
return cropBitmap();
}
@Override
protected void onPostExecute(Boolean result) {
...
}
}
首先初始化碘梢，然后執(zhí)行doInBackground方法咬摇，其實(shí)這個(gè)方法中執(zhí)行的是cropBitmap方法，代碼：
public boolean cropBitmap() {
...
if (mSetWallpaper) {
//獲取WallpaperManager對(duì)象
wallpaperManager = WallpaperManager.getInstance(mContext.getApplicationContext());
}
if (mSetWallpaper && mNoCrop) {
try {
//不需要裁切的情況下煞躬，直接通過URI獲取圖片流
InputStream is = regenerateInputStream();
if (is != null) {
//如果圖片存在肛鹏，設(shè)置壁紙
wallpaperManager.setStream(is);
Utils.closeSilently(is);
}
} catch (IOException e) {
Log.w(LOGTAG, "cannot write stream to wallpaper", e);
failure = true;
}
return !failure;
} else {// 如果需要裁切
// Find crop bounds (scaled to original image size)
...
//獲取圖片的大小范圍
Point bounds = getImageBounds();
//判斷是否需要旋轉(zhuǎn)
if (mRotation > 0) {
rotateMatrix.setRotate(mRotation);
inverseRotateMatrix.setRotate(-mRotation);
...
}
mCropBounds.roundOut(roundedTrueCrop);
//如果寬高小于0則視為失敗
if (roundedTrueCrop.width() <= 0 || roundedTrueCrop.height() <= 0) {
...
return false;
}
// 根據(jù)寬高比來設(shè)置縮放倍數(shù)
int scaleDownSampleSize = Math.max(1, Math.min(roundedTrueCrop.width() / mOutWidth,
roundedTrueCrop.height() / mOutHeight));
...
try {
//通過流讀取圖片
is = regenerateInputStream();
...
decoder = BitmapRegionDecoder.newInstance(is, false);
Utils.closeSilently(is);
} catch (IOException e) {
...
} finally {
...
}
Bitmap crop = null;
if (decoder != null) {
// Do region decoding to get crop bitmap
BitmapFactory.Options options = new BitmapFactory.Options();
if (scaleDownSampleSize > 1) {
options.inSampleSize = scaleDownSampleSize;
}
// 獲取切割圖片
crop = decoder.decodeRegion(roundedTrueCrop, options);
decoder.recycle();
}
if (crop == null) {//獲取切割圖片失敗
// BitmapRegionDecoder has failed, try to crop in-memory
is = regenerateInputStream();
Bitmap fullSize = null;
if (is != null) {
BitmapFactory.Options options = new BitmapFactory.Options();
if (scaleDownSampleSize > 1) {
options.inSampleSize = scaleDownSampleSize;
}
//獲取原始圖片
fullSize = BitmapFactory.decodeStream(is, null, options);
Utils.closeSilently(is);
}
if (fullSize != null) {
// 計(jì)算切割圖片的范圍
...
//生成切割圖片
crop = Bitmap.createBitmap(fullSize, roundedTrueCrop.left,
roundedTrueCrop.top, roundedTrueCrop.width(),
roundedTrueCrop.height());
}
}
...
if (mOutWidth > 0 && mOutHeight > 0 || mRotation > 0) {
...
Matrix m = new Matrix();
// 不需要旋轉(zhuǎn)
if (mRotation == 0) {
m.setRectToRect(cropRect, returnRect, Matrix.ScaleToFit.FILL);
} else {//旋轉(zhuǎn)
...
}
//生成新的旋轉(zhuǎn)后的圖片
Bitmap tmp = Bitmap.createBitmap((int) returnRect.width(),
(int) returnRect.height(), Bitmap.Config.ARGB_8888);
if (tmp != null) {
Canvas c = new Canvas(tmp);
Paint p = new Paint();
p.setFilterBitmap(true);
c.drawBitmap(crop, m, p);
crop = tmp;
}
}
if (mSaveCroppedBitmap) {
mCroppedBitmap = crop;
}
// Compress to byte array
ByteArrayOutputStream tmpOut = new ByteArrayOutputStream(2048);
//壓縮圖片成數(shù)組
if (crop.compress(CompressFormat.JPEG, DEFAULT_COMPRESS_QUALITY, tmpOut)) {
// If we need to set to the wallpaper, set it
if (mSetWallpaper && wallpaperManager != null) {
try {
byte[] outByteArray = tmpOut.toByteArray();
//設(shè)置壁紙
wallpaperManager.setStream(new ByteArrayInputStream(outByteArray));
if (mOnBitmapCroppedHandler != null) {
mOnBitmapCroppedHandler.onBitmapCropped(outByteArray);
}
} catch (IOException e) {
...
}
}
} else {
...
}
}
return !failure; // True if any of the operations failed
整個(gè)過程看上面代碼，解釋都卸載注釋里面了恩沛，一些裁切計(jì)算問題看看代碼就知道了在扰，最終就是轉(zhuǎn)換成流的形式進(jìn)行設(shè)置壁紙。
最后
原文地址：墨香博客
Github地址：https://github.com/yuchuangu85/Launcher3_mx/tree/launcher3_6.0
Android開發(fā)群：192508518
微信公眾賬號(hào)：Code-MX
注：本文原創(chuàng)雷客，轉(zhuǎn)載請(qǐng)注明出處芒珠，多謝。
