我开发了一些应用程序，它运行正常，没有任何问题。调试没问题。我使用ShareActionProvider类方法创建了一些自定义类，以检查ActionShareProvider菜单中的用户操作。当我想从Android Studio生成APK时，它会给我这个错误;
错误：（87）错误：此类应提供默认构造函数（不带参数的公共构造函数）（com.esmobileinc.vetmapp.ShareActionProvider）[Instantiatable]
有ShareActionProvider类;
public class ShareActionProvider extends ActionProvider {
public void setOnShareListener(OnShareListener listener) {
mOnShareListener = listener;
setActivityChooserPolicyIfNeeded();
}
/**
* Listener for the event of selecting a share target.
*/
public interface OnShareTargetSelectedListener {
/**
* Called when a share target has been selected. The client can
* decide whether to perform some action before the sharing is
* actually performed.
* <p>
* <strong>Note:</strong> Modifying the intent is not permitted and
* any changes to the latter will be ignored.
* </p>
* <p>
* <strong>Note:</strong> You should <strong>not</strong> handle the
* intent here. This callback aims to notify the client that a
* sharing is being performed, so the client can update the UI
* if necessary.
* </p>
*
* @param source The source of the notification.
* @param intent The intent for launching the chosen share target.
* @return The return result is ignored. Always return false for consistency.
*/
public boolean onShareTargetSelected(ShareActionProvider source, Intent intent);
}
private OnShareListener mOnShareListener; //also need to add getter and setter
public interface OnShareListener {
/**
* Called when a share target has been selected. The client can
* decide whether to perform some action before the sharing is
* actually performed OR handle the action itself.
*
* @param source The source of the notification.
* @param intent The intent for launching the chosen share target.
* @return Return true if you have handled the intent.
*/
public boolean willHandleShareTarget(ShareActionProvider source, Intent intent);
}
/**
* The default for the maximal number of activities shown in the sub-menu.
*/
private static final int DEFAULT_INITIAL_ACTIVITY_COUNT = 4;
/**
* The the maximum number activities shown in the sub-menu.
*/
private int mMaxShownActivityCount = DEFAULT_INITIAL_ACTIVITY_COUNT;
/**
* Listener for handling menu item clicks.
*/
private final ShareMenuItemOnMenuItemClickListener mOnMenuItemClickListener =
new ShareMenuItemOnMenuItemClickListener();
/**
* The default name for storing share history.
*/
public static final String DEFAULT_SHARE_HISTORY_FILE_NAME = "share_history.xml";
/**
* Context for accessing resources.
*/
private final Context mContext;
/**
* The name of the file with share history data.
*/
private String mShareHistoryFileName = DEFAULT_SHARE_HISTORY_FILE_NAME;
private OnShareTargetSelectedListener mOnShareTargetSelectedListener;
private OnChooseActivityListener mOnChooseActivityListener;
/**
* Creates a new instance.
*
* @param context Context for accessing resources.
*/
public ShareActionProvider(Context context) {
super(context);
mContext = context;
}
/**
* Sets a listener to be notified when a share target has been selected.
* The listener can optionally decide to handle the selection and
* not rely on the default behavior which is to launch the activity.
* <p>
* <strong>Note:</strong> If you choose the backing share history file
* you will still be notified in this callback.
* </p>
* @param listener The listener.
*/
public void setOnShareTargetSelectedListener(OnShareTargetSelectedListener listener) {
mOnShareTargetSelectedListener = listener;
setActivityChooserPolicyIfNeeded();
}
/**
* {@inheritDoc}
*/
@Override
public View onCreateActionView() {
// Create the view and set its data model.
ActivityChooserView activityChooserView = new ActivityChooserView(mContext);
if (!activityChooserView.isInEditMode()) {
ActivityChooserModel dataModel = ActivityChooserModel.get(mContext, mShareHistoryFileName);
activityChooserView.setActivityChooserModel(dataModel);
}
// Lookup and set the expand action icon.
TypedValue outTypedValue = new TypedValue();
mContext.getTheme().resolveAttribute(R.attr.actionModeShareDrawable, outTypedValue, true);
Drawable drawable = TintManager.getDrawable(mContext, outTypedValue.resourceId);
activityChooserView.setExpandActivityOverflowButtonDrawable(drawable);
activityChooserView.setProvider(this);
// Set content description.
activityChooserView.setDefaultActionButtonContentDescription(
R.string.abc_shareactionprovider_share_with_application);
activityChooserView.setExpandActivityOverflowButtonContentDescription(
R.string.abc_shareactionprovider_share_with);
return activityChooserView;
}
/**
* {@inheritDoc}
*/
@Override
public boolean hasSubMenu() {
return true;
}
/**
* {@inheritDoc}
*/
@Override
public void onPrepareSubMenu(SubMenu subMenu) {
// Clear since the order of items may change.
subMenu.clear();
ActivityChooserModel dataModel = ActivityChooserModel.get(mContext, mShareHistoryFileName);
PackageManager packageManager = mContext.getPackageManager();
final int expandedActivityCount = dataModel.getActivityCount();
final int collapsedActivityCount = Math.min(expandedActivityCount, mMaxShownActivityCount);
// Populate the sub-menu with a sub set of the activities.
for (int i = 0; i < collapsedActivityCount; i++) {
ResolveInfo activity = dataModel.getActivity(i);
subMenu.add(0, i, i, activity.loadLabel(packageManager))
.setIcon(activity.loadIcon(packageManager))
.setOnMenuItemClickListener(mOnMenuItemClickListener);
}
if (collapsedActivityCount < expandedActivityCount) {
// Add a sub-menu for showing all activities as a list item.
SubMenu expandedSubMenu = subMenu.addSubMenu(Menu.NONE, collapsedActivityCount,
collapsedActivityCount,
mContext.getString(R.string.abc_activity_chooser_view_see_all));
for (int i = 0; i < expandedActivityCount; i++) {
ResolveInfo activity = dataModel.getActivity(i);
expandedSubMenu.add(0, i, i, activity.loadLabel(packageManager))
.setIcon(activity.loadIcon(packageManager))
.setOnMenuItemClickListener(mOnMenuItemClickListener);
}
}
}
/**
* Sets the file name of a file for persisting the share history which
* history will be used for ordering share targets. This file will be used
* for all view created by {@link #onCreateActionView()}. Defaults to
* {@link #DEFAULT_SHARE_HISTORY_FILE_NAME}. Set to <code>null</code>
* if share history should not be persisted between sessions.
* <p>
* <strong>Note:</strong> The history file name can be set any time, however
* only the action views created by {@link #onCreateActionView()} after setting
* the file name will be backed by the provided file. Therefore, if you want to
* use different history files for sharing specific types of content, every time
* you change the history file {@link #setShareHistoryFileName(String)} you must
* call {@link android.app.Activity#invalidateOptionsMenu()} to recreate the
* action view. You should <strong>not</strong> call
* {@link android.app.Activity#invalidateOptionsMenu()} from
* {@link android.app.Activity#onCreateOptionsMenu(Menu)}."
* <p>
* <code>
* private void doShare(Intent intent) {
* if (IMAGE.equals(intent.getMimeType())) {
* mShareActionProvider.setHistoryFileName(SHARE_IMAGE_HISTORY_FILE_NAME);
* } else if (TEXT.equals(intent.getMimeType())) {
* mShareActionProvider.setHistoryFileName(SHARE_TEXT_HISTORY_FILE_NAME);
* }
* mShareActionProvider.setIntent(intent);
* invalidateOptionsMenu();
* }
* <code>
*
* @param shareHistoryFile The share history file name.
*/
public void setShareHistoryFileName(String shareHistoryFile) {
mShareHistoryFileName = shareHistoryFile;
setActivityChooserPolicyIfNeeded();
}
/**
* Sets an intent with information about the share action. Here is a
* sample for constructing a share intent:
* <p>
* <pre>
* <code>
* Intent shareIntent = new Intent(Intent.ACTION_SEND);
* shareIntent.setType("image/*");
* Uri uri = Uri.fromFile(new File(getFilesDir(), "foo.jpg"));
* shareIntent.putExtra(Intent.EXTRA_STREAM, uri.toString());
* </pre>
* </code>
* </p>
*
* @param shareIntent The share intent.
*
* @see Intent#ACTION_SEND
* @see Intent#ACTION_SEND_MULTIPLE
*/
public void setShareIntent(Intent shareIntent) {
if (shareIntent != null) {
final String action = shareIntent.getAction();
if (Intent.ACTION_SEND.equals(action) || Intent.ACTION_SEND_MULTIPLE.equals(action)) {
updateIntent(shareIntent);
}
}
ActivityChooserModel dataModel = ActivityChooserModel.get(mContext,
mShareHistoryFileName);
dataModel.setIntent(shareIntent);
}
/**
* Reusable listener for handling share item clicks.
*/
private class ShareMenuItemOnMenuItemClickListener implements OnMenuItemClickListener {
@Override
public boolean onMenuItemClick(MenuItem item) {
ActivityChooserModel dataModel = ActivityChooserModel.get(mContext,
mShareHistoryFileName);
final int itemId = item.getItemId();
Intent launchIntent = dataModel.chooseActivity(itemId);
if (launchIntent != null) {
final String action = launchIntent.getAction();
if (Intent.ACTION_SEND.equals(action) ||
Intent.ACTION_SEND_MULTIPLE.equals(action)) {
updateIntent(launchIntent);
}
mContext.startActivity(launchIntent);
}
return true;
}
}
/**
* Set the activity chooser policy of the model backed by the current
* share history file if needed which is if there is a registered callback.
*/
private void setActivityChooserPolicyIfNeeded() {
if (mOnShareListener == null) {
return;
}
if (mOnChooseActivityListener == null) {
mOnChooseActivityListener = new ShareActivityChooserModelPolicy();
}
ActivityChooserModel dataModel = ActivityChooserModel.get(mContext, mShareHistoryFileName);
dataModel.setOnChooseActivityListener(mOnChooseActivityListener);
}
/**
* Policy that delegates to the {@link OnShareTargetSelectedListener}, if such.
*/
private class ShareActivityChooserModelPolicy implements OnChooseActivityListener {
@Override
public boolean onChooseActivity(ActivityChooserModel host, Intent intent) {
if (mOnShareListener != null) {
boolean result = mOnShareListener.willHandleShareTarget(
ShareActionProvider.this, intent);
return result;
}
return false;
}
}
private void updateIntent(Intent intent) {
if (Build.VERSION.SDK_INT >= 21) {
// If we're on Lollipop, we can open the intent as a document
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_DOCUMENT |
Intent.FLAG_ACTIVITY_MULTIPLE_TASK);
} else {
// Else, we will use the old CLEAR_WHEN_TASK_RESET flag
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
}
}
}
我的ShareActionProvider类中有一个构造函数;
public ShareActionProvider(Context context) {
super(context);
mContext = context;
}
为什么它会给我这个错误？我怎么解决这个问题。谢谢！
答案 0 :(得分：1)
我将自定义ActionShareProvider.class重命名为CustomActionShareProvider.class并解决了问题。