Launcher3源码分析(CellLayout)

CellLayout是workspace的屏幕。 CellLayout中的一些重要属性:

int mCellWidth; int mCellHeight; //每一个屏幕的行列数 int mCountX;//每一行的item个数 int mCountY;//每一列的item个数 //item之间的距离 int mWidthGap;//item之间的宽度 int mHeightGap;//item之间的高度

构造方法

public CellLayout(Context context, AttributeSet attrs, int defStyle){ super(context,attrs,defStyle){ setWillNotDraw(false); setClipToPadding(false); mLauncher = (Launcher)context; DeviceProfile grid = mLauncher.getDeviceProfile(); TypedArray a = context.obtainStyledAttributes(attrs,R.styleable.CellLayout,defStyle,0); mCellWidth = mCellHeight = -1; mFixedCellWidth = mFixedCellHeight = -1; //item之间的距离 mWidthGap = mOriginalWidthGap = 0; mHeightGap = mOriginalHeightGap = 0; mMaxGap = Integer.MAX_VALUE; //每屏幕上的item行数列数 //DeviceProfile grid = app.getDynamicGrid().getDeviceProfile();grid是DeviceProfile的对象 mCountX = (int) grid.inv.numColumns; mcountY = (int) grid.inv.numRows; mOccupied = new boolean[mCountX][mCountY]; mTmpOccupied = new boolean[mCountX][mCountY]; …… final Resources res = getResources(); mHotseatScale = (float) grid.hotseatIconSizePx / grid.iconSizePx; //CellLayout缩略图背景，即长按屏幕空白处时CellLayout缩小时的背景图 mBackground = (TransitionDrawable) res.getDrawable(R.drawable.bg_screenpanel); mBackground.setCallback(this); …… } }

在Workspace.java中加载CellLayout的布局，代码如下：

public long insertNewWorkspaceScreen(long screenId, int insertIndex){ if (mWorkspaceScreens.containsKey(screenId)) { throw new RuntimeException("Screen id " + screenId + " already exists!"); } // Inflate the cell layout, but do not add it automatically so //that we can get the newly created CellLayout. //加载CellLayout布局 CellLayout newScreen = (CellLayout)mLauncher.getLayoutInflater().inflate(R.layout.workspace_screen,this,false); }

CellLayout中的一个item可以占多个Cell,CellInfo记录item的起始坐标、占多少格

public static final class CellInfo{ View cell; int cellX = -1; int cellY = -1; int spanX; int spanY; long screenId; long container; public CellInfo(View v, ItemInfo info){ cell = v; cellX = info.cellX; cellY = info.cellY; spanX = info.spanX; spanY = info.spanY; screenId = info.screenId; container = info.cotainer; } }

CellLayout的触摸事件

public boolean onInterceptTouchEvent(MotionEvent ev){ if(mUseTouchHelper || (mInterceptTouchListener != null && mInterceptTouchListener.onTouch(this,ev)){ return true; } return false; } public boolean onTouchEvent(MotionEvent ev){ boolean handled = super.onTouchEvent(ev); //检查workspace是否处在预览模式 if(mLauncher.mWorkspace.isInOverviewMode() && mStylusEventHelper.checkAndPerformStylusEvent(ev)){ return true; } return handled; }

设置cell间距、占格数的大小

public void setCellDimensions(int width, int height); public void setGridSize(int x, int y);