墨香带你学Launcher之(七)--小部件的加载、添加以及大小调节

上一章墨香带你学Launcher之(六)--拖拽我们介绍了Launcher的拖拽过程,涉及到的范围比较广,包括图标的拖拽,桌面上CellLayout的拖拽,小部件的拖拽,以及跨不同部件的拖拽,设计思想非常巧妙,不过整个流程相对也比较好掌握,只要跟着上一章的流程自己多跟踪几遍基本就熟悉了。按照计划本章我们继续学习Launcher的Widget的加载、添加以及Widget的大小调节。

Widget的数据加载

其实我们在第二章墨香带你学Launcher之(二)-数据加载流程介绍过Widget数据的加载,相对只是简单的做了介绍,下面我们稍微讲的详细点。

我们知道Widget的数据加载开始在LauncherModel中的updateWidgetsModel方法中,我们看下代码:

    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);
    }

上面代码我们可以看到是通过调用getWidgetProviders(mApp.getContext(), refresh)方法来获取所有Widget的,代码:

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) {
            ...    
        }
    }

我们看到首先是初始化AppWidgetManagerCompat,我们之前介绍过带有Compat的是兼容组件,我们看看是怎么兼容的,

launcher01.png

我们下面代码:

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;
        }
    }

我们可以看到AppWidgetManagerCompat的初始化有两个,一个是当Api版本高于21(包含21)时,用AppWidgetManagerCompatVL,低于21时用AppWidgetManagerCompatV16,这两个有什么不同,我们下面分析。

下面我们看如何获取Widget列表对象:

List<AppWidgetProviderInfo> widgets = wm.getAllProviders();

getAllProviders()方法是一个抽象方法,所以我们看哪里进行了复写,

launcher02.png

可以看到还是上面两个兼容类复写了该方法,我们看这个两个类中做了什么处理,先看V16中的:

    @Override
    public List<AppWidgetProviderInfo> getAllProviders() {
        return mAppWidgetManager.getInstalledProviders();
    }

我们再看mAppWidgetManager这个是在哪里初始化,

    @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);
        }
    }

里面有个if语句,我们可以看到当Api大于等于17时,调用第一个进行初始化,否则调用第二个方法进行初始化,这就是对不同手机版本做的兼容。在我们写App的时候如果遇到相似情况也可以这么处理。

我们再看一下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中的不一样了,这里面是通过for循环来获取的,其中有个UserHandle,那么在源码中给出的解释是设备中的每个用户,个人理解应该是每个应用,每个应用会有0-N个Widget,也就是从每个应用中获取每个应用的Widget列表。这样for循环就可以获取整个手机中所有应用的widget列表了。

再回到上面getWidgetProviders方法的代码中,我们接着看,接着for循环AppWidgetProviderInfo列表信息,重构LauncherAppWidgetProviderInfo对象,这里有点怪,为啥有了AppWidgetProviderInfo对象还要重构一个LauncherAppWidgetProviderInfo对象,我们知道在写插件的时候每个Widget都会有一个类继承AppWidgetProvider,这样才会有一个插件,因此我们知道AppWidgetProviderInfo对象肯定是AppWidgetProvider的对象,那么LauncherAppWidgetProviderInfo是什么,我们接着看能不能找到答案,LauncherAppWidgetProviderInfo的初始化时通过

LauncherAppWidgetProviderInfo.fromProviderInfo(context, pInfo);

方法进行初始化的,我们再看LauncherAppWidgetProviderInfo又继承AppWidgetProviderInfo,越来越怪,我们接着看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;
    }

我们看到最后是通过new LauncherAppWidgetProviderInfo来生成一个LauncherAppWidgetProviderInfo对象,那么这个对象构造函数中有什么:

    public LauncherAppWidgetProviderInfo(Parcel in) {
        super(in);
        initSpans();
    }

这个构造函数调用了initSpans方法,我们接着追寻:

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));
    }

这段代码也不难,是为了算四个参数:spanX、spanY、minSpanX、minSpanY,看过我前面博客的都知道这个spanX和spanY参数是什么,其实这个LauncherAppWidgetProviderInfo对象比系统自带的AppWidgetProviderInfo带有的就是多了这几个参数,也就是方便我们添加到桌面是计算占用位置。

最后得到HashMap<ComponentKey, LauncherAppWidgetProviderInfo>这个Widget集合,最后通过

mBgWidgetsModel.setWidgetsAndShortcuts(widgetsAndShortcuts);

将这个集合放到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.
        ...
        }
    }

在这里将不同应用的Widget放到同一个列表中然后在放到mWidgetsList中,以供应加载Widget列表。接着执行绑定过程,绑定过程我们在第三章墨香带你学Launcher之(三)-绑定屏幕、图标、文件夹和Widget介绍过,但是里面还有些东西在这里需要介绍一下,我们看源码知道其实Widget是通过适配器放置到WidgetsRecyclerView里面的,WidgetsRecyclerView是一个RecyclerView,而每个Widget视图是一个WidgetCell,那么WidgetCell是什么,我们看WidgetsListAdapter适配器,这个我们就不详细介绍了,在里面的onBindViewHolder方法中对WidgetCell进行了初始化,其中在里面会调动下面方法:

widget.applyFromAppWidgetProviderInfo(info, mWidgetPreviewLoader);

我们看看这个方法:

 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;
    }

上面代码通过mWidgetName.setText显示名字,通过mWidgetDims.setText显示大小。最后给mWidgetPreviewLoader赋值,我们看到这个loader是从WidgetsListAdapter中传递进来的,在WidgetsListAdapter中,是通过LauncherAppState.getInstance().getWidgetCache()获取的,其实这个loader是在LauncherAppState初始化的时候就初始化了。

在WidgetCell初始化后调用了widget.ensurePreview()方法:

 public void ensurePreview() {
        ...
        int[] size = getPreviewSize();
        mActiveRequest = mWidgetPreviewLoader.getPreview(mInfo, size[0], size[1], this);
    }

在这里调用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);
    }

在这里执行了一个异步任务PreviewLoadTask,我们看一下这个异步任务,首先看doInBackground方法:

...
preview = generatePreview(launcher, mInfo, unusedBitmap, mPreviewWidth, mPreviewHeight);
...

接着看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);
        }
    }

我们看到是生成一个Bitmap,然后调用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) {
            // 获取相对应的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);
    }

整个过程就是从系统加载出Widget对应的Drawable然后绘制到Bitmap上面返回,然后在onPostExecute方法中将该图片添加到WidgetCell上面,就显示到了WidgetCell列表中。整个加载就完成了。

Widget的添加:

我们之前讲过,Widget列表最后是绑定到WidgetsContainerView中的,而我们将Widget放置到桌面是通过长按拖拽到桌面来完成的,因此我们可以知道添加的触发事件是通过长按事件来触发的,因为我们找到WidgetsContainerView中的长按事件:

    @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;
    }

首先调用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的视图(WidgetCell)也就是长按的是Widget布局则调用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;
    }

上面代码中的generateWidgetPreview方法我们在上面已经讲过了,就是生产WidgetCell图片的,然后锁定屏幕旋转,然后调用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);
    }

整个方法在拖拽中讲过,就是在workspace中生成一个拖拽view的轮廓边框,然后调用mDragController.startDrag方法,之后的过程在拖拽章节中有很详细的讲解,所以在此不再重复了,没看过拖拽的可以去看拖拽过程详解。下面只是个提示过程。

在放置到桌面时会调用onDrop方法,然后调用onDropExternal方法,然后调用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则调用addAppWidgetFromDrop方法,然后调用addAppWidgetImpl方法,然后调用completeAddAppWidget方法,最后调用mWorkspace.addInScreen方法就讲WidgetCell添加到了桌面上。

Widget的大小调节:

我们在桌面上添加完Widget后,如果长按你会发现在Widget四个边缘会出现拖动框,如果拖动可以调节小插件的大小,那么这个拖动框在哪里添加的呢,我们看一下,其实这个方法是DragLayer中的addResizeFrame方法,这个方法是在Workspace中的onDrop方法中调用的,也就是放到桌面上的时候就添加了。

我们看一下这个方法:

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);
    }

首先创建AppWidgetResizeFrame对象,传入参数LauncherAppWidgetHostView、CellLayout,还有draglayer:

    public AppWidgetResizeFrame(Context context,
            LauncherAppWidgetHostView widgetView, CellLayout cellLayout, DragLayer dragLayer) {

        //初始化数据
        ...
        
        // 初始化左侧拖动点
        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);

        // 初始化右侧拖动点
        // 初始化顶部拖动点
        // 初始化底部拖动点

        ...
    }

拖动调整大小是在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);
    }

由上面代码可以看出拖拽的的时候调用visualizeResizeForDelta方法,手指抬起的时候调用visualizeResizeForDelta方法和onTouchUp方法,我们先看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();
    }

首先调用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);
        }
    }

主要是根据上下左右点来计算mDeltaX和mDeltaY的值,然后设定DragLayer.LayoutParams的值,然后调用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();
    }

这里计算拖拽过程中的参数,然后调用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);
    }

首先调用getWidgetSizeRanges方法来设定sTmpRect参数,然后调用widgetView.updateAppWidgetSize方法更新widget大小,然后调用mWidgetView.requestLayout方法刷新widget。

我们再看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);
            }
        });
    }

这个方法是调整完widget大小手指离开屏幕时调用的,主要调用了snapToWidget方法,这个方法代码就不贴了,主要是四个点的动画,代码很简单。

到此widget的加载、添加以及大小调整就介绍完了,整个过程也是比较复杂的,所以还是要好好熟悉一下。

最后

同步发布:http://www.codemx.cn/2016/12/18/Launcher07/

Github地址:https://github.com/yuchuangu85/Launcher3_mx

微信公众账号:Code-MX

qr_code_mx.jpg

注:本文原创,转载请注明出处,多谢。

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