上一章墨香帶你學(xué)Launcher之（六）--拖拽我們介紹了Launcher的拖拽過程，涉及到的范圍比較廣辛块，包括圖標(biāo)的拖拽畔派，桌面上CellLayout的拖拽，小部件的拖拽润绵，以及跨不同部件的拖拽线椰，設(shè)計(jì)思想非常巧妙，不過整個流程相對也比較好掌握尘盼，只要跟著上一章的流程自己多跟蹤幾遍基本就熟悉了憨愉。按照計(jì)劃本章我們繼續(xù)學(xué)習(xí)Launcher的Widget的加載烦绳、添加以及Widget的大小調(diào)節(jié)。
Widget的數(shù)據(jù)加載
其實(shí)我們在第二章墨香帶你學(xué)Launcher之（二）-數(shù)據(jù)加載流程介紹過Widget數(shù)據(jù)的加載配紫，相對只是簡單的做了介紹径密，下面我們稍微講的詳細(xì)點(diǎn)。
我們知道Widget的數(shù)據(jù)加載開始在LauncherModel中的updateWidgetsModel方法中躺孝，我們看下代碼：
void updateWidgetsModel(boolean refresh) {
PackageManager packageManager = mApp.getContext().getPackageManager();
final ArrayList<Object> widgetsAndShortcuts = new ArrayList<Object>();
widgetsAndShortcuts.addAll(getWidgetProviders(mApp.getContext(), refresh));
Intent shortcutsIntent = new Intent(Intent.ACTION_CREATE_SHORTCUT);
widgetsAndShortcuts.addAll(packageManager.queryIntentActivities(shortcutsIntent, 0));
mBgWidgetsModel.setWidgetsAndShortcuts(widgetsAndShortcuts);
}
上面代碼我們可以看到是通過調(diào)用getWidgetProviders(mApp.getContext(), refresh)方法來獲取所有Widget的享扔，代碼：
public static List<LauncherAppWidgetProviderInfo> getWidgetProviders(Context context,
boolean refresh) {
ArrayList<LauncherAppWidgetProviderInfo> results =
new ArrayList<LauncherAppWidgetProviderInfo>();
try {
synchronized (sBgLock) {
if (sBgWidgetProviders == null || refresh) {
HashMap<ComponentKey, LauncherAppWidgetProviderInfo> tmpWidgetProviders
= new HashMap<>();
AppWidgetManagerCompat wm = AppWidgetManagerCompat.getInstance(context);
LauncherAppWidgetProviderInfo info;
List<AppWidgetProviderInfo> widgets = wm.getAllProviders();
for (AppWidgetProviderInfo pInfo : widgets) {
info = LauncherAppWidgetProviderInfo.fromProviderInfo(context, pInfo);
UserHandleCompat user = wm.getUser(info);
tmpWidgetProviders.put(new ComponentKey(info.provider, user), info);
}
Collection<CustomAppWidget> customWidgets = Launcher.getCustomAppWidgets().values();
for (CustomAppWidget widget : customWidgets) {
info = new LauncherAppWidgetProviderInfo(context, widget);
UserHandleCompat user = wm.getUser(info);
tmpWidgetProviders.put(new ComponentKey(info.provider, user), info);
}
// Replace the global list at the very end, so that if there is an exception,
// previously loaded provider list is used.
sBgWidgetProviders = tmpWidgetProviders;
}
results.addAll(sBgWidgetProviders.values());
return results;
}
} catch (Exception e) {
...
}
}
我們看到首先是初始化AppWidgetManagerCompat，我們之前介紹過帶有Compat的是兼容組件植袍，我們看看是怎么兼容的惧眠，
我們下面代碼：
public static AppWidgetManagerCompat getInstance(Context context) {
synchronized (sInstanceLock) {
if (sInstance == null) {
if (Utilities.ATLEAST_LOLLIPOP) {
sInstance = new AppWidgetManagerCompatVL(context.getApplicationContext());
} else {
sInstance = new AppWidgetManagerCompatV16(context.getApplicationContext());
}
}
return sInstance;
}
}
我們可以看到AppWidgetManagerCompat的初始化有兩個，一個是當(dāng)Api版本高于21（包含21）時于个，用AppWidgetManagerCompatVL氛魁，低于21時用AppWidgetManagerCompatV16，這兩個有什么不同厅篓，我們下面分析秀存。
下面我們看如何獲取Widget列表對象：
List<AppWidgetProviderInfo> widgets = wm.getAllProviders();
getAllProviders()方法是一個抽象方法，所以我們看哪里進(jìn)行了復(fù)寫羽氮，
可以看到還是上面兩個兼容類復(fù)寫了該方法或链，我們看這個兩個類中做了什么處理，先看V16中的：
@Override
public List<AppWidgetProviderInfo> getAllProviders() {
return mAppWidgetManager.getInstalledProviders();
}
我們再看mAppWidgetManager這個是在哪里初始化乏苦，
@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
@Override
public boolean bindAppWidgetIdIfAllowed(int appWidgetId, AppWidgetProviderInfo info,
Bundle options) {
if (Utilities.ATLEAST_JB_MR1) {
return mAppWidgetManager.bindAppWidgetIdIfAllowed(appWidgetId, info.provider, options);
} else {
return mAppWidgetManager.bindAppWidgetIdIfAllowed(appWidgetId, info.provider);
}
}
里面有個if語句株扛，我們可以看到當(dāng)Api大于等于17時，調(diào)用第一個進(jìn)行初始化汇荐，否則調(diào)用第二個方法進(jìn)行初始化洞就，這就是對不同手機(jī)版本做的兼容。在我們寫App的時候如果遇到相似情況也可以這么處理掀淘。
我們再看一下VL中的getAllProviders()方法：
@Override
public List<AppWidgetProviderInfo> getAllProviders() {
ArrayList<AppWidgetProviderInfo> providers = new ArrayList<AppWidgetProviderInfo>();
for (UserHandle user : mUserManager.getUserProfiles()) {
providers.addAll(mAppWidgetManager.getInstalledProvidersForProfile(user));
}
return providers;
}
和V16中的不一樣了旬蟋，這里面是通過for循環(huán)來獲取的，其中有個UserHandle革娄，那么在源碼中給出的解釋是設(shè)備中的每個用戶倾贰，個人理解應(yīng)該是每個應(yīng)用，每個應(yīng)用會有0-N個Widget拦惋，也就是從每個應(yīng)用中獲取每個應(yīng)用的Widget列表匆浙。這樣for循環(huán)就可以獲取整個手機(jī)中所有應(yīng)用的widget列表了。
再回到上面getWidgetProviders方法的代碼中厕妖，我們接著看首尼，接著for循環(huán)AppWidgetProviderInfo列表信息，重構(gòu)LauncherAppWidgetProviderInfo對象，這里有點(diǎn)怪软能，為啥有了AppWidgetProviderInfo對象還要重構(gòu)一個LauncherAppWidgetProviderInfo對象迎捺，我們知道在寫插件的時候每個Widget都會有一個類繼承AppWidgetProvider，這樣才會有一個插件查排，因此我們知道AppWidgetProviderInfo對象肯定是AppWidgetProvider的對象凳枝，那么LauncherAppWidgetProviderInfo是什么，我們接著看能不能找到答案跋核，LauncherAppWidgetProviderInfo的初始化時通過
LauncherAppWidgetProviderInfo.fromProviderInfo(context, pInfo);
方法進(jìn)行初始化的,我們再看LauncherAppWidgetProviderInfo又繼承AppWidgetProviderInfo岖瑰，越來越怪，我們接著看fromProviderInfo(context, pInfo)方法：
public static LauncherAppWidgetProviderInfo fromProviderInfo(Context context,
AppWidgetProviderInfo info) {
Parcel p = Parcel.obtain();
info.writeToParcel(p, 0);
p.setDataPosition(0);
LauncherAppWidgetProviderInfo lawpi = new LauncherAppWidgetProviderInfo(p);
p.recycle();
return lawpi;
}
我們看到最后是通過new LauncherAppWidgetProviderInfo來生成一個LauncherAppWidgetProviderInfo對象砂代，那么這個對象構(gòu)造函數(shù)中有什么：
public LauncherAppWidgetProviderInfo(Parcel in) {
super(in);
initSpans();
}
這個構(gòu)造函數(shù)調(diào)用了initSpans方法锭环，我們接著追尋：
private void initSpans() {
LauncherAppState app = LauncherAppState.getInstance();
InvariantDeviceProfile idp = app.getInvariantDeviceProfile();
// We only care out the cell size, which is independent of the the layout direction.
Rect paddingLand = idp.landscapeProfile.getWorkspacePadding(false /* isLayoutRtl */);
Rect paddingPort = idp.portraitProfile.getWorkspacePadding(false /* isLayoutRtl */);
// Always assume we're working with the smallest span to make sure we
// reserve enough space in both orientations.
float smallestCellWidth = DeviceProfile.calculateCellWidth(Math.min(
idp.landscapeProfile.widthPx - paddingLand.left - paddingLand.right,
idp.portraitProfile.widthPx - paddingPort.left - paddingPort.right),
idp.numColumns);
float smallestCellHeight = DeviceProfile.calculateCellWidth(Math.min(
idp.landscapeProfile.heightPx - paddingLand.top - paddingLand.bottom,
idp.portraitProfile.heightPx - paddingPort.top - paddingPort.bottom),
idp.numRows);
// We want to account for the extra amount of padding that we are adding to the widget
// to ensure that it gets the full amount of space that it has requested.
Rect widgetPadding = AppWidgetHostView.getDefaultPaddingForWidget(
app.getContext(), provider, null);
spanX = Math.max(1, (int) Math.ceil(
(minWidth + widgetPadding.left + widgetPadding.right) / smallestCellWidth));
spanY = Math.max(1, (int) Math.ceil(
(minHeight + widgetPadding.top + widgetPadding.bottom) / smallestCellHeight));
minSpanX = Math.max(1, (int) Math.ceil(
(minResizeWidth + widgetPadding.left + widgetPadding.right) / smallestCellWidth));
minSpanY = Math.max(1, (int) Math.ceil(
(minResizeHeight + widgetPadding.top + widgetPadding.bottom) / smallestCellHeight));
}
這段代碼也不難，是為了算四個參數(shù)：spanX泊藕、spanY、minSpanX难礼、minSpanY娃圆，看過我前面博客的都知道這個spanX和spanY參數(shù)是什么，其實(shí)這個LauncherAppWidgetProviderInfo對象比系統(tǒng)自帶的AppWidgetProviderInfo帶有的就是多了這幾個參數(shù)蛾茉，也就是方便我們添加到桌面是計(jì)算占用位置讼呢。
最后得到HashMap<ComponentKey, LauncherAppWidgetProviderInfo>這個Widget集合，最后通過
mBgWidgetsModel.setWidgetsAndShortcuts(widgetsAndShortcuts);
將這個集合放到WidgetsModel中：
public void setWidgetsAndShortcuts(ArrayList<Object> rawWidgetsShortcuts) {
...
HashMap<String, PackageItemInfo> tmpPackageItemInfos = new HashMap<>();
// clear the lists.
...
InvariantDeviceProfile idp = LauncherAppState.getInstance().getInvariantDeviceProfile();
// add and update.
for (Object o: rawWidgetsShortcuts) {
String packageName = "";
UserHandleCompat userHandle = null;
ComponentName componentName = null;
if (o instanceof LauncherAppWidgetProviderInfo) {
LauncherAppWidgetProviderInfo widgetInfo = (LauncherAppWidgetProviderInfo) o;
// Ensure that all widgets we show can be added on a workspace of this size
int minSpanX = Math.min(widgetInfo.spanX, widgetInfo.minSpanX);
int minSpanY = Math.min(widgetInfo.spanY, widgetInfo.minSpanY);
if (minSpanX <= (int) idp.numColumns &&
minSpanY <= (int) idp.numRows) {
componentName = widgetInfo.provider;
packageName = widgetInfo.provider.getPackageName();
userHandle = mAppWidgetMgr.getUser(widgetInfo);
} else {
...
continue;
}
} else if (o instanceof ResolveInfo) {
ResolveInfo resolveInfo = (ResolveInfo) o;
componentName = new ComponentName(resolveInfo.activityInfo.packageName,
resolveInfo.activityInfo.name);
packageName = resolveInfo.activityInfo.packageName;
userHandle = UserHandleCompat.myUserHandle();
}
if (componentName == null || userHandle == null) {
...
continue;
}
...
PackageItemInfo pInfo = tmpPackageItemInfos.get(packageName);
ArrayList<Object> widgetsShortcutsList = mWidgetsList.get(pInfo);
if (widgetsShortcutsList != null) {
widgetsShortcutsList.add(o);
} else {
widgetsShortcutsList = new ArrayList<>();
widgetsShortcutsList.add(o);
pInfo = new PackageItemInfo(packageName);
mIconCache.getTitleAndIconForApp(packageName, userHandle,
true /* userLowResIcon */, pInfo);
pInfo.titleSectionName = mIndexer.computeSectionName(pInfo.title);
mWidgetsList.put(pInfo, widgetsShortcutsList);
tmpPackageItemInfos.put(packageName, pInfo);
mPackageItemInfos.add(pInfo);
}
}
// 排序.
...
}
}
在這里將不同應(yīng)用的Widget放到同一個列表中然后在放到mWidgetsList中谦炬，以供應(yīng)加載Widget列表悦屏。接著執(zhí)行綁定過程，綁定過程我們在第三章墨香帶你學(xué)Launcher之（三）-綁定屏幕键思、圖標(biāo)础爬、文件夾和Widget介紹過，但是里面還有些東西在這里需要介紹一下吼鳞，我們看源碼知道其實(shí)Widget是通過適配器放置到WidgetsRecyclerView里面的看蚜，WidgetsRecyclerView是一個RecyclerView，而每個Widget視圖是一個WidgetCell赔桌，那么WidgetCell是什么供炎，我們看WidgetsListAdapter適配器，這個我們就不詳細(xì)介紹了疾党，在里面的onBindViewHolder方法中對WidgetCell進(jìn)行了初始化音诫，其中在里面會調(diào)動下面方法：
widget.applyFromAppWidgetProviderInfo(info, mWidgetPreviewLoader);
我們看看這個方法：
public void applyFromAppWidgetProviderInfo(LauncherAppWidgetProviderInfo info,
WidgetPreviewLoader loader) {
InvariantDeviceProfile profile =
LauncherAppState.getInstance().getInvariantDeviceProfile();
mInfo = info;
// TODO(hyunyoungs): setup a cache for these labels.
mWidgetName.setText(AppWidgetManagerCompat.getInstance(getContext()).loadLabel(info));
int hSpan = Math.min(info.spanX, profile.numColumns);
int vSpan = Math.min(info.spanY, profile.numRows);
mWidgetDims.setText(String.format(mDimensionsFormatString, hSpan, vSpan));
mWidgetPreviewLoader = loader;
}
上面代碼通過mWidgetName.setText顯示名字，通過mWidgetDims.setText顯示大小雪位。最后給mWidgetPreviewLoader賦值竭钝，我們看到這個loader是從WidgetsListAdapter中傳遞進(jìn)來的，在WidgetsListAdapter中，是通過LauncherAppState.getInstance().getWidgetCache()獲取的蜓氨，其實(shí)這個loader是在LauncherAppState初始化的時候就初始化了聋袋。
在WidgetCell初始化后調(diào)用了widget.ensurePreview()方法：
public void ensurePreview() {
...
int[] size = getPreviewSize();
mActiveRequest = mWidgetPreviewLoader.getPreview(mInfo, size[0], size[1], this);
}
在這里調(diào)用mWidgetPreviewLoader.getPreview方法：
public PreviewLoadRequest getPreview(final Object o, int previewWidth,
int previewHeight, WidgetCell caller) {
String size = previewWidth + "x" + previewHeight;
WidgetCacheKey key = getObjectKey(o, size);
PreviewLoadTask task = new PreviewLoadTask(key, o, previewWidth, previewHeight, caller);
task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
return new PreviewLoadRequest(task);
}
在這里執(zhí)行了一個異步任務(wù)PreviewLoadTask，我們看一下這個異步任務(wù)穴吹，首先看doInBackground方法：
...
preview = generatePreview(launcher, mInfo, unusedBitmap, mPreviewWidth, mPreviewHeight);
...
接著看generatePreview方法：
Bitmap generatePreview(Launcher launcher, Object info, Bitmap recycle,
int previewWidth, int previewHeight) {
if (info instanceof LauncherAppWidgetProviderInfo) {
return generateWidgetPreview(launcher, (LauncherAppWidgetProviderInfo) info,
previewWidth, recycle, null);
} else {
return generateShortcutPreview(launcher,
(ResolveInfo) info, previewWidth, previewHeight, recycle);
}
}
我們看到是生成一個Bitmap幽勒，然后調(diào)用generateWidgetPreview生成Bitmap：
public Bitmap generateWidgetPreview(Launcher launcher, LauncherAppWidgetProviderInfo info,
int maxPreviewWidth, Bitmap preview, int[] preScaledWidthOut) {
// Load the preview image if possible
if (maxPreviewWidth < 0) maxPreviewWidth = Integer.MAX_VALUE;
Drawable drawable = null;
if (info.previewImage != 0) {
// 獲取相對應(yīng)的drawable
drawable = mManager.loadPreview(info);
...
}
// Draw the scaled preview into the final bitmap
int x = (preview.getWidth() - previewWidth) / 2;
if (widgetPreviewExists) {
drawable.setBounds(x, 0, x + previewWidth, previewHeight);
drawable.draw(c);
} else {
...
for (int i = 0; i < spanX; i++, tx += tileW) {
float ty = 0;
for (int j = 0; j < spanY; j++, ty += tileH) {
dst.offsetTo(tx, ty);
c.drawBitmap(tileBitmap, src, dst, p);
}
}
...
try {
Drawable icon = mutateOnMainThread(mManager.loadIcon(info, mIconCache));
if (icon != null) {
...
icon.draw(c);
}
} catch (Resources.NotFoundException e) { }
c.setBitmap(null);
}
int imageHeight = Math.min(preview.getHeight(), previewHeight + mProfileBadgeMargin);
return mManager.getBadgeBitmap(info, preview, imageHeight);
}
整個過程就是從系統(tǒng)加載出Widget對應(yīng)的Drawable然后繪制到Bitmap上面返回，然后在onPostExecute方法中將該圖片添加到WidgetCell上面港令，就顯示到了WidgetCell列表中啥容。整個加載就完成了。
Widget的添加：
我們之前講過咪惠，Widget列表最后是綁定到WidgetsContainerView中的，而我們將Widget放置到桌面是通過長按拖拽到桌面來完成的淋淀，因此我們可以知道添加的觸發(fā)事件是通過長按事件來觸發(fā)的遥昧，因?yàn)槲覀冋业絎idgetsContainerView中的長按事件：
@Override
public boolean onLongClick(View v) {
...
boolean status = beginDragging(v);
if (status && v.getTag() instanceof PendingAddWidgetInfo) {
WidgetHostViewLoader hostLoader = new WidgetHostViewLoader(mLauncher, v);
boolean preloadStatus = hostLoader.preloadWidget();
...
mLauncher.getDragController().addDragListener(hostLoader);
}
return status;
}
首先調(diào)用beginDragging方法：
private boolean beginDragging(View v) {
if (v instanceof WidgetCell) {
if (!beginDraggingWidget((WidgetCell) v)) {
return false;
}
} else {
Log.e(TAG, "Unexpected dragging view: " + v);
}
// We don't enter spring-loaded mode if the drag has been cancelled
if (mLauncher.getDragController().isDragging()) {
// Go into spring loaded mode (must happen before we startDrag())
mLauncher.enterSpringLoadedDragMode();
}
return true;
}
如果是Widget的視圖（WidgetCell）也就是長按的是Widget布局則調(diào)用beginDraggingWidget方法：
private boolean beginDraggingWidget(WidgetCell v) {
WidgetImageView image = (WidgetImageView) v.findViewById(R.id.widget_preview);
...
if (createItemInfo instanceof PendingAddWidgetInfo) {
...
Bitmap icon = image.getBitmap();
float minScale = 1.25f;
int maxWidth = Math.min((int) (icon.getWidth() * minScale), size[0]);
...
preview = getWidgetPreviewLoader().generateWidgetPreview(mLauncher,
createWidgetInfo.info, maxWidth, null, previewSizeBeforeScale);
...
scale = bounds.width() / (float) preview.getWidth();
} else {
// shortcut
...
}
// Don't clip alpha values for the drag outline if we're using the default widget preview
boolean clipAlpha = !(createItemInfo instanceof PendingAddWidgetInfo &&
(((PendingAddWidgetInfo) createItemInfo).previewImage == 0));
// Start the drag
mLauncher.lockScreenOrientation();
mLauncher.getWorkspace().onDragStartedWithItem(createItemInfo, preview, clipAlpha);
mDragController.startDrag(image, preview, this, createItemInfo,
bounds, DragController.DRAG_ACTION_COPY, scale);
preview.recycle();
return true;
}
上面代碼中的generateWidgetPreview方法我們在上面已經(jīng)講過了，就是生產(chǎn)WidgetCell圖片的朵纷，然后鎖定屏幕旋轉(zhuǎn)炭臭，然后調(diào)用onDragStartedWithItem方法：
public void onDragStartedWithItem(PendingAddItemInfo info, Bitmap b, boolean clipAlpha) {
int[] size = estimateItemSize(info, false);
// The outline is used to visualize where the item will land if dropped
mDragOutline = createDragOutline(b, DRAG_BITMAP_PADDING, size[0], size[1], clipAlpha);
}
整個方法在拖拽中講過，就是在workspace中生成一個拖拽view的輪廓邊框袍辞，然后調(diào)用mDragController.startDrag方法鞋仍，之后的過程在拖拽章節(jié)中有很詳細(xì)的講解，所以在此不再重復(fù)了搅吁，沒看過拖拽的可以去看拖拽過程詳解威创。下面只是個提示過程。
在放置到桌面時會調(diào)用onDrop方法谎懦，然后調(diào)用onDropExternal方法肚豺，然后調(diào)用addPendingItem方法：
public void addPendingItem(PendingAddItemInfo info, long container, long screenId,
int[] cell, int spanX, int spanY) {
switch (info.itemType) {
case LauncherSettings.Favorites.ITEM_TYPE_CUSTOM_APPWIDGET:
case LauncherSettings.Favorites.ITEM_TYPE_APPWIDGET:
int span[] = new int[2];
span[0] = spanX;
span[1] = spanY;
addAppWidgetFromDrop((PendingAddWidgetInfo) info,
container, screenId, cell, span);
break;
...
}
}
如果是Widget則調(diào)用addAppWidgetFromDrop方法，然后調(diào)用addAppWidgetImpl方法党瓮，然后調(diào)用completeAddAppWidget方法详炬，最后調(diào)用mWorkspace.addInScreen方法就講WidgetCell添加到了桌面上。
Widget的大小調(diào)節(jié)：
我們在桌面上添加完Widget后寞奸，如果長按你會發(fā)現(xiàn)在Widget四個邊緣會出現(xiàn)拖動框呛谜，如果拖動可以調(diào)節(jié)小插件的大小，那么這個拖動框在哪里添加的呢枪萄，我們看一下隐岛，其實(shí)這個方法是DragLayer中的addResizeFrame方法，這個方法是在Workspace中的onDrop方法中調(diào)用的瓷翻，也就是放到桌面上的時候就添加了聚凹。
我們看一下這個方法：
public void addResizeFrame(ItemInfo itemInfo, LauncherAppWidgetHostView widget,
CellLayout cellLayout) {
AppWidgetResizeFrame resizeFrame = new AppWidgetResizeFrame(getContext(),
widget, cellLayout, this);
LayoutParams lp = new LayoutParams(-1, -1);
lp.customPosition = true;
addView(resizeFrame, lp);
mResizeFrames.add(resizeFrame);
resizeFrame.snapToWidget(false);
}
首先創(chuàng)建AppWidgetResizeFrame對象割坠，傳入?yún)?shù)LauncherAppWidgetHostView、CellLayout妒牙，還有draglayer：
public AppWidgetResizeFrame(Context context,
LauncherAppWidgetHostView widgetView, CellLayout cellLayout, DragLayer dragLayer) {
//初始化數(shù)據(jù)
...
// 初始化左側(cè)拖動點(diǎn)
mLeftHandle = new ImageView(context);
mLeftHandle.setImageResource(R.drawable.ic_widget_resize_handle);
lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT,
Gravity.LEFT | Gravity.CENTER_VERTICAL);
lp.leftMargin = handleMargin;
addView(mLeftHandle, lp);
// 初始化右側(cè)拖動點(diǎn)
// 初始化頂部拖動點(diǎn)
// 初始化底部拖動點(diǎn)
...
}
拖動調(diào)整大小是在DragLayer中的onTouchEvent方法中：
@Override
public boolean onTouchEvent(MotionEvent ev) {
...
if (mCurrentResizeFrame != null) {
handled = true;
switch (action) {
case MotionEvent.ACTION_MOVE:
mCurrentResizeFrame.visualizeResizeForDelta(x - mXDown, y - mYDown);
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
mCurrentResizeFrame.visualizeResizeForDelta(x - mXDown, y - mYDown);
mCurrentResizeFrame.onTouchUp();
mCurrentResizeFrame = null;
}
}
if (handled) return true;
return mDragController.onTouchEvent(ev);
}
由上面代碼可以看出拖拽的的時候調(diào)用visualizeResizeForDelta方法彼哼，手指抬起的時候調(diào)用visualizeResizeForDelta方法和onTouchUp方法，我們先看visualizeResizeForDelta方法：
private void visualizeResizeForDelta(int deltaX, int deltaY, boolean onDismiss) {
updateDeltas(deltaX, deltaY);
DragLayer.LayoutParams lp = (DragLayer.LayoutParams) getLayoutParams();
if (mLeftBorderActive) {
lp.x = mBaselineX + mDeltaX;
lp.width = mBaselineWidth - mDeltaX;
} else if (mRightBorderActive) {
lp.width = mBaselineWidth + mDeltaX;
}
if (mTopBorderActive) {
lp.y = mBaselineY + mDeltaY;
lp.height = mBaselineHeight - mDeltaY;
} else if (mBottomBorderActive) {
lp.height = mBaselineHeight + mDeltaY;
}
resizeWidgetIfNeeded(onDismiss);
requestLayout();
}
首先調(diào)用updateDeltas方法：
public void updateDeltas(int deltaX, int deltaY) {
if (mLeftBorderActive) {
mDeltaX = Math.max(-mBaselineX, deltaX);
mDeltaX = Math.min(mBaselineWidth - 2 * mTouchTargetWidth, mDeltaX);
} else if (mRightBorderActive) {
mDeltaX = Math.min(mDragLayer.getWidth() - (mBaselineX + mBaselineWidth), deltaX);
mDeltaX = Math.max(-mBaselineWidth + 2 * mTouchTargetWidth, mDeltaX);
}
if (mTopBorderActive) {
mDeltaY = Math.max(-mBaselineY, deltaY);
mDeltaY = Math.min(mBaselineHeight - 2 * mTouchTargetWidth, mDeltaY);
} else if (mBottomBorderActive) {
mDeltaY = Math.min(mDragLayer.getHeight() - (mBaselineY + mBaselineHeight), deltaY);
mDeltaY = Math.max(-mBaselineHeight + 2 * mTouchTargetWidth, mDeltaY);
}
}
主要是根據(jù)上下左右點(diǎn)來計(jì)算mDeltaX和mDeltaY的值湘今，然后設(shè)定DragLayer.LayoutParams的值敢朱，然后調(diào)用resizeWidgetIfNeeded方法：
private void resizeWidgetIfNeeded(boolean onDismiss) {
...
if (mLeftBorderActive) {
cellXInc = Math.max(-cellX, hSpanInc);
cellXInc = Math.min(lp.cellHSpan - mMinHSpan, cellXInc);
hSpanInc *= -1;
hSpanInc = Math.min(cellX, hSpanInc);
hSpanInc = Math.max(-(lp.cellHSpan - mMinHSpan), hSpanInc);
hSpanDelta = -hSpanInc;
}
...
// Update the widget's dimensions and position according to the deltas computed above
if (mLeftBorderActive || mRightBorderActive) {
spanX += hSpanInc;
cellX += cellXInc;
if (hSpanDelta != 0) {
mDirectionVector[0] = mLeftBorderActive ? -1 : 1;
}
}
...
if (mCellLayout.createAreaForResize(cellX, cellY, spanX, spanY, mWidgetView,
mDirectionVector, onDismiss)) {
lp.tmpCellX = cellX;
lp.tmpCellY = cellY;
lp.cellHSpan = spanX;
lp.cellVSpan = spanY;
mRunningVInc += vSpanDelta;
mRunningHInc += hSpanDelta;
if (!onDismiss) {
updateWidgetSizeRanges(mWidgetView, mLauncher, spanX, spanY);
}
}
mWidgetView.requestLayout();
}
這里計(jì)算拖拽過程中的參數(shù)，然后調(diào)用updateWidgetSizeRanges方法：
static void updateWidgetSizeRanges(AppWidgetHostView widgetView, Launcher launcher,
int spanX, int spanY) {
getWidgetSizeRanges(launcher, spanX, spanY, sTmpRect);
widgetView.updateAppWidgetSize(null, sTmpRect.left, sTmpRect.top,
sTmpRect.right, sTmpRect.bottom);
}
首先調(diào)用getWidgetSizeRanges方法來設(shè)定sTmpRect參數(shù)摩瞎，然后調(diào)用widgetView.updateAppWidgetSize方法更新widget大小拴签，然后調(diào)用mWidgetView.requestLayout方法刷新widget。
我們再看onTouchUp方法：
public void onTouchUp() {
int xThreshold = mCellLayout.getCellWidth() + mCellLayout.getWidthGap();
int yThreshold = mCellLayout.getCellHeight() + mCellLayout.getHeightGap();
...
post(new Runnable() {
@Override
public void run() {
snapToWidget(true);
}
});
}
這個方法是調(diào)整完widget大小手指離開屏幕時調(diào)用的旗们，主要調(diào)用了snapToWidget方法蚓哩，這個方法代碼就不貼了，主要是四個點(diǎn)的動畫上渴，代碼很簡單岸梨。
到此widget的加載、添加以及大小調(diào)整就介紹完了稠氮，整個過程也是比較復(fù)雜的盛嘿，所以還是要好好熟悉一下。
最后
同步發(fā)布：http://www.codemx.cn/2016/12/18/Launcher07/
Github地址：https://github.com/yuchuangu85/Launcher3_mx
微信公眾賬號：Code-MX
注：本文原創(chuàng)括袒，轉(zhuǎn)載請注明出處，多謝稿茉。
