在launcher中，长按屏幕，图挂了，我们在代码里面找一下：
首先，找到onLongClick(View v)方法，然后在这个方法中，有如下代码：
if (mWorkspace.allowLongPress()) {
if (cellInfo.cell == null) {
if (cellInfo.valid) {
// User long pressed on empty space
mWorkspace.setAllowLongPress(false);
showAddDialog(cellInfo);
}
} else {
if (!(cellInfo.cell instanceof Folder)) {
// User long pressed on an item
mWorkspace.startDrag(cellInfo);
}
}
}
然后，继续追踪showAddDialog（）方法：
private void showAddDialog(CellLayout.CellInfo cellInfo) {
mAddItemCellInfo = cellInfo;
mWaitingForResult = true;
showDialog(DIALOG_CREATE_SHORTCUT);
}
继续找showDialog,没什么发现，showDialog()方法是该类父类Activity()方法，携带参数DIALOG_CREATE_SHORTCUT，但是它最后是调用的Launcher.java的onCreateDialog(int id)这个方法：
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_CREATE_SHORTCUT:
return new CreateShortcut().createDialog();
在这里，使用了CreateShortcut.createDialog()方法，在源代码的2708行：
private class CreateShortcut implements DialogInterface.OnClickListener,
DialogInterface.OnCancelListener, DialogInterface.OnDismissListener,
DialogInterface.OnShowListener {
private AddAdapter mAdapter;
Dialog createDialog() {
mWaitingForResult = true;
mAdapter = new AddAdapter(Launcher.this);
final AlertDialog.Builder builder = new AlertDialog.Builder(Launcher.this);
builder.setTitle(getString(R.string.menu_item_add_item));
builder.setAdapter(mAdapter, this);
builder.setInverseBackgroundForced(true);
AlertDialog dialog = builder.create();
dialog.setOnCancelListener(this);
dialog.setOnDismissListener(this);
dialog.setOnShowListener(this);
return dialog;
}
public void onCancel(DialogInterface dialog) {
mWaitingForResult = false;
cleanup();
}
public void onDismiss(DialogInterface dialog) {
mWorkspace.unlock();
}
private void cleanup() {
mWorkspace.unlock();
dismissDialog(DIALOG_CREATE_SHORTCUT);
}
/**
* Handle the action clicked in the "Add to home" dialog.
*/
public void onClick(DialogInterface dialog, int which) {
Resources res = getResources();
cleanup();
switch (which) {
case AddAdapter.ITEM_SHORTCUT: {
// Insert extra item to handle picking application
pickShortcut(REQUEST_PICK_SHORTCUT, R.string.title_select_shortcut);
break;
}
case AddAdapter.ITEM_APPWIDGET: {
int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId();
Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);
pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
// add the search widget
ArrayList<AppWidgetProviderInfo> customInfo =
new ArrayList<AppWidgetProviderInfo>();
AppWidgetProviderInfo info = new AppWidgetProviderInfo();
info.provider = new ComponentName(getPackageName(), "XXX.YYY");
info.label = getString(R.string.group_search);
info.icon = R.drawable.ic_search_widget;
customInfo.add(info);
pickIntent.putParcelableArrayListExtra(
AppWidgetManager.EXTRA_CUSTOM_INFO, customInfo);
ArrayList<Bundle> customExtras = new ArrayList<Bundle>();
Bundle b = new Bundle();
b.putString(EXTRA_CUSTOM_WIDGET, SEARCH_WIDGET);
customExtras.add(b);
pickIntent.putParcelableArrayListExtra(
AppWidgetManager.EXTRA_CUSTOM_EXTRAS, customExtras);
// start the pick activity
startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);
break;
}
case AddAdapter.ITEM_LIVE_FOLDER: {
// Insert extra item to handle inserting folder
Bundle bundle = new Bundle();
ArrayList<String> shortcutNames = new ArrayList<String>();
shortcutNames.add(res.getString(R.string.group_folder));
bundle.putStringArrayList(Intent.EXTRA_SHORTCUT_NAME, shortcutNames);
ArrayList<ShortcutIconResource> shortcutIcons =
new ArrayList<ShortcutIconResource>();
shortcutIcons.add(ShortcutIconResource.fromContext(Launcher.this,
R.drawable.ic_launcher_folder));
bundle.putParcelableArrayList(Intent.EXTRA_SHORTCUT_ICON_RESOURCE, shortcutIcons);
Intent pickIntent = new Intent(Intent.ACTION_PICK_ACTIVITY);
pickIntent.putExtra(Intent.EXTRA_INTENT,
new Intent(LiveFolders.ACTION_CREATE_LIVE_FOLDER));
pickIntent.putExtra(Intent.EXTRA_TITLE,
getText(R.string.title_select_live_folder));
pickIntent.putExtras(bundle);
startActivityForResult(pickIntent, REQUEST_PICK_LIVE_FOLDER);
break;
}
case AddAdapter.ITEM_WALLPAPER: {
startWallpaper();
break;
}
case AddAdapter.ITEM_ANYCUT: {
Intent anycutIntent=new Intent();
anycutIntent.setClass(Launcher.this, CustomShirtcutActivity.class);
startActivityForResult(anycutIntent, REQUEST_PICK_ANYCUT);
break;
}
}
}
public void onShow(DialogInterface dialog) {
mWorkspace.lock();
}
}
我们可以在CreateShortcut类中onclick()方法里面找到一下代码（这里是2.2的代码）：
case AddAdapter.ITEM_APPWIDGET: {
int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId();
Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);
pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
// add the search widget
ArrayList<AppWidgetProviderInfo> customInfo =
new ArrayList<AppWidgetProviderInfo>();
AppWidgetProviderInfo info = new AppWidgetProviderInfo();
info.provider = new ComponentName(getPackageName(), "XXX.YYY");
info.label = getString(R.string.group_search);
info.icon = R.drawable.ic_search_widget;
customInfo.add(info);
pickIntent.putParcelableArrayListExtra(
AppWidgetManager.EXTRA_CUSTOM_INFO, customInfo);
ArrayList<Bundle> customExtras = new ArrayList<Bundle>();
Bundle b = new Bundle();
b.putString(EXTRA_CUSTOM_WIDGET, SEARCH_WIDGET);
customExtras.add(b);
pickIntent.putParcelableArrayListExtra(
AppWidgetManager.EXTRA_CUSTOM_EXTRAS, customExtras);
// start the pick activity
startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);
break;
}
这里是2.3的代码：
case AddAdapter.ITEM_APPWIDGET: {
int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId();
Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);
pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
// start the pick activity
startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);
break;
}
在这里又是如何实现的呢？我么看到了startActivityForResult()方法，它实际上是运行了package/apps/Settings/src/com/android/settings/AppWidgetPickActivity.java
我们来看下代码中是如何获取widget信息的：
void putAppWidgetItems(List<AppWidgetProviderInfo> appWidgets,
List<Bundle> customExtras, List<PickAdapter.Item> items) {
if (appWidgets == null) return;
final int size = appWidgets.size();
for (int i = 0; i < size; i++) {
AppWidgetProviderInfo info = appWidgets.get(i);
Drawable icon = null;
CharSequence label = info.label;
if (info.icon != 0) {
icon = mPackageManager.getDrawable(info.provider.getPackageName(), info.icon, null);
if (icon == null) {
Log.w(TAG, "Can't load icon drawable 0x" + Integer.toHexString(info.icon)
+ " for provider: " + info.provider);
}
}
PickAdapter.Item item = new PickAdapter.Item(this, label, icon);
item.packageName = info.provider.getPackageName();
item.className = info.provider.getClassName();
if (customExtras != null) {
item.extras = customExtras.get(i);
}
items.add(item);
}
和方法：
@Override
protected List<PickAdapter.Item> getItems() {
List<PickAdapter.Item> items = new ArrayList<PickAdapter.Item>();
putInstalledAppWidgets(items);
putCustomAppWidgets(items);
// Sort all items together by label
Collections.sort(items, new Comparator<PickAdapter.Item>() {
Collator mCollator = Collator.getInstance();
public int compare(PickAdapter.Item lhs, PickAdapter.Item rhs) {
return mCollator.compare(lhs.label, rhs.label);
}
});
return items;
}
下面是我自己写的获取widget的图标：
List<AppWidgetProviderInfo> mAppinfoList = mAppWidgetManager.getInstalledProviders();
List<Drawable> mIconList=new ArrayList();
for(AppWidgetProviderInfo appWidgetInfo:mAppinfoList)
{
Drawable icon = null;
PackageManager packageManager = getPackageManager();
icon = packageManager.getDrawable(appWidgetInfo.provider.getPackageName(), appWidgetInfo.icon, null);
mIconList.add(icon);
}
在这段代码里，能获取widget的列表。
不知道是何种原因，使用以下代码：
List<AppWidgetProviderInfo> mAppinfoList = mAppWidgetManager.getInstalledProviders();
for(AppWidgetProviderInfo appWidgetInfo:mAppinfoList)
{
mThumbs.add(appWidgetInfo.icon);
}
却不能获取widget的图标，而是别的图，望清楚原因者告知。