Implement a bluetooth picker dialog for Android

chrome/android/java/src/org/chromium/chrome/browser/ItemChooserDialog.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser;
 
 import android.app.Dialog;
 import android.content.Context;
+import android.content.DialogInterface;
 import android.graphics.Color;
 import android.graphics.drawable.ColorDrawable;
 import android.text.SpannableString;
 import android.text.method.LinkMovementMethod;
 import android.util.DisplayMetrics;
 import android.view.Gravity;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;
 import android.view.Window;
 import android.view.WindowManager;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
 import android.widget.Button;
 import android.widget.LinearLayout;
 import android.widget.ListView;
 import android.widget.ProgressBar;
 import android.widget.TextView;
 
 import org.chromium.chrome.R;
 import org.chromium.ui.base.DeviceFormFactor;
 import org.chromium.ui.widget.TextViewWithClickableSpans;
 
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 /**
  * A general-purpose dialog for presenting a list of things to pick from.
  */
 public class ItemChooserDialog {
     /**
      * An interface to implement to get a callback when something has been
      * selected.
      */
     public interface ItemSelectedCallback {
@@ skipping 24 matching lines @@
      */
     public static class ItemChooserLabels {
         // The title at the top of the dialog.
         public final SpannableString mTitle;
         // The message to show while results are trickling in.
         public final String mSearching;
         // The message to show when no results were produced.
         public final SpannableString mNoneFound;
         // A status message to show above the button row.
         public final SpannableString mStatus;
+        // An error state.
+        public final SpannableString mErrorMessage;
+        // A status message to go with the error state.
+        public final SpannableString mErrorStatus;
         // The label for the positive button (e.g. Select/Pair).
         public final String mPositiveButton;
 
         public ItemChooserLabels(SpannableString title, String searching, SpannableString noneFound,
-                SpannableString status, String positiveButton) {
+                SpannableString status, SpannableString errorMessage, SpannableString errorStatus,
+                String positiveButton) {
             mTitle = title;
             mSearching = searching;
             mNoneFound = noneFound;
             mStatus = status;
+            mErrorMessage = errorMessage;
+            mErrorStatus = errorStatus;
             mPositiveButton = positiveButton;
         }
     }
 
     /**
+     * The various states the dialog can represent.
+     */
+    private enum State {
+        STARTING,
+        PROGRESS_UPDATE_AVAILABLE,
+        SHOWING_ERROR,
+    }
+
+    /**
      * An adapter for keeping track of which items to show in the dialog.
      */
     private class ItemAdapter extends ArrayAdapter<ItemChooserRow>
             implements AdapterView.OnItemClickListener {
         private final LayoutInflater mInflater;
 
         // The background color of the highlighted item.
         private final int mBackgroundHighlightColor;
 
         // The color of the non-highlighted text.
         private final int mDefaultTextColor;
 
         // The zero-based index of the item currently selected in the dialog,
         // or -1 (INVALID_POSITION) if nothing is selected.
         private int mSelectedItem = ListView.INVALID_POSITION;
 
+        // A set of keys that are marked as disabled in the dialog.
+        private Set<String> mDisabledEntries = new HashSet<String>();
+
         public ItemAdapter(Context context, int resource) {
             super(context, resource);
 
             mInflater = LayoutInflater.from(context);
 
             mBackgroundHighlightColor = getContext().getResources().getColor(
                     R.color.light_active_color);
             mDefaultTextColor = getContext().getResources().getColor(
                     R.color.default_text_color);
         }
 
         @Override
         public void clear() {
             mSelectedItem = ListView.INVALID_POSITION;
             mConfirmButton.setEnabled(false);
             super.clear();
         }
 
         /**
          * Returns the key of the currently selected item or blank if nothing is
          * selected.
          */
         public String getSelectedItemKey() {
             ItemChooserRow row = getItem(mSelectedItem);
             if (row == null) return "";
             return row.mKey;
         }
 
+        /**
+         * Sets whether the itam is enabled. Disabled items are grayed out.
+         * @param id The id of the item to affect.
+         * @param enabled Whether the item should be enabled or not.
+         */
+        public void setEnabled(String id, boolean enabled) {
+            if (enabled) {
+                mDisabledEntries.remove(id);
+            } else {
+                mDisabledEntries.add(id);
+            }
+            notifyDataSetChanged();
+        }
+
+        @Override
+        public boolean isEnabled(int position) {
+            ItemChooserRow item = getItem(position);
+            return !mDisabledEntries.contains(item.mKey);
+        }
+
         @Override
         public int getViewTypeCount() {
             return 1;
         }
 
         @Override
         public long getItemId(int position) {
             return position;
         }
 
         @Override
         public View getView(int position, View convertView, ViewGroup parent) {
             TextView view;
             if (convertView instanceof TextView) {
                 view = (TextView) convertView;
             } else {
                 view = (TextView) mInflater.inflate(
                         R.layout.item_chooser_dialog_row, parent, false);
             }
 
             // Set highlighting for currently selected item.
             if (position == mSelectedItem) {
                 view.setBackgroundColor(mBackgroundHighlightColor);
                 view.setTextColor(Color.WHITE);
             } else {
                 view.setBackground(null);
-                view.setTextColor(mDefaultTextColor);
+                if (!isEnabled(position)) {
+                    view.setTextColor(getContext().getResources().getColor(
+                            R.color.primary_text_disabled_material_light));
+                } else {
+                    view.setTextColor(mDefaultTextColor);
+                }
             }
 
             ItemChooserRow item = getItem(position);
             view.setText(item.mDescription);
             return view;
         }
 
         @Override
         public void onItemClick(AdapterView<?> adapter, View view, int position, long id) {
             mSelectedItem = position;
             mConfirmButton.setEnabled(true);
             mItemAdapter.notifyDataSetChanged();
         }
     }
 
     private Context mContext;
 
     // The dialog this class encapsulates.
     private Dialog mDialog;
 
     // The callback to notify when the user selected an item.
     private ItemSelectedCallback mItemSelectedCallback;
 
     // Individual UI elements.
     private TextViewWithClickableSpans mTitle;
-    private TextViewWithClickableSpans mNotFoundMessage;
+    private TextViewWithClickableSpans mEmptyMessage;
     private ProgressBar mProgressBar;
     private ListView mListView;
     private TextView mStatus;
     private Button mConfirmButton;
 
     // The labels to display in the dialog.
     private ItemChooserLabels mLabels;
 
     // The adapter containing the items to show in the dialog.
     private ItemAdapter mItemAdapter;
@@ skipping 19 matching lines @@
         mLabels = labels;
 
         LinearLayout dialogContainer = (LinearLayout) LayoutInflater.from(
                 mContext).inflate(R.layout.item_chooser_dialog, null);
 
         mListView = (ListView) dialogContainer.findViewById(R.id.items);
         mProgressBar = (ProgressBar) dialogContainer.findViewById(R.id.progress);
         mStatus = (TextView) dialogContainer.findViewById(R.id.status);
         mTitle = (TextViewWithClickableSpans) dialogContainer.findViewById(
                 R.id.dialog_title);
-        mNotFoundMessage =
-                (TextViewWithClickableSpans) dialogContainer.findViewById(
-                        R.id.not_found_message);
+        mEmptyMessage =
+                (TextViewWithClickableSpans) dialogContainer.findViewById(R.id.not_found_message);
 
         mTitle.setText(labels.mTitle);
         mTitle.setMovementMethod(LinkMovementMethod.getInstance());
 
-        mNotFoundMessage.setText(labels.mNoneFound);
-        mNotFoundMessage.setMovementMethod(LinkMovementMethod.getInstance());
-
-        mStatus.setText(labels.mSearching);
+        mEmptyMessage.setMovementMethod(LinkMovementMethod.getInstance());
         mStatus.setMovementMethod(LinkMovementMethod.getInstance());
 
         mConfirmButton = (Button) dialogContainer.findViewById(R.id.positive);
         mConfirmButton.setText(labels.mPositiveButton);
         mConfirmButton.setEnabled(false);
         mConfirmButton.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 mItemSelectedCallback.onItemSelected(
                         mItemAdapter.getSelectedItemKey());
                 mDialog.dismiss();
             }
         });
 
         mItemAdapter = new ItemAdapter(mContext, R.layout.item_chooser_dialog_row);
         mListView.setAdapter(mItemAdapter);
-        mListView.setEmptyView(mNotFoundMessage);
-        mNotFoundMessage.setVisibility(View.GONE);
+        mListView.setEmptyView(mEmptyMessage);
         mListView.setOnItemClickListener(mItemAdapter);
         mListView.setDivider(null);
+        setState(State.STARTING);
 
         // The list is the main element in the dialog and it should grow and
         // shrink according to the size of the screen available (clamped to a
         // min and a max).
         View listViewContainer = dialogContainer.findViewById(R.id.container);
         DisplayMetrics metrics = new DisplayMetrics();
         WindowManager manager = (WindowManager) mContext.getSystemService(
                 Context.WINDOW_SERVICE);
         manager.getDefaultDisplay().getMetrics(metrics);
 
         float density = context.getResources().getDisplayMetrics().density;
         int height = (int) (metrics.heightPixels * LISTVIEW_HEIGHT_PERCENT);
         height = Math.min(height, Math.round(MAX_HEIGHT_DP * density));
         height = Math.max(height, Math.round(MIN_HEIGHT_DP * density));
         listViewContainer.setLayoutParams(
                 new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, height));
 
         showDialogForView(dialogContainer);
     }
 
     private void showDialogForView(View view) {
         mDialog = new Dialog(mContext);
         mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
         mDialog.addContentView(view,
                 new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,
                                               LinearLayout.LayoutParams.MATCH_PARENT));
+        mDialog.setOnDismissListener(new DialogInterface.OnDismissListener() {
+            @Override
+            public void onDismiss(DialogInterface dialog) {
+                mItemSelectedCallback.onItemSelected("");

[newt (away), 2015/09/02 17:48:42]

Seems like you'll end up calling onItemSelected() twice if the user clicks the
confirm button: once with the selected item's key and once with the empty
string. Is that what you want?

[Finnur, 2015/09/03 11:51:45]

Both handlers do, indeed, fire, but the second message never reaches the native
level. However, it isn't necessary to keep the onDismiss handler once the
onClick handler (for the commit button fires), so I now null it there just to
make sure.

+            }
+        });
 
         Window window = mDialog.getWindow();
         if (!DeviceFormFactor.isTablet(mContext)) {
             // On smaller screens, make the dialog fill the width of the screen,
             // and appear at the top.
             window.setBackgroundDrawable(new ColorDrawable(Color.WHITE));
             window.setGravity(Gravity.TOP);
             window.setLayout(ViewGroup.LayoutParams.MATCH_PARENT,
                              ViewGroup.LayoutParams.WRAP_CONTENT);
         }
 
         mDialog.show();
     }
 
+    public void dismiss() {
+        mDialog.dismiss();
+    }
+
     /**
      * Add items to show in the dialog.
      *
      * @param list The list of items to show. This function can be called
      * multiple times to add more items and new items will be appended to
      * the end of the list. An empty list should be used if there are no
      * items to show.
      */
     public void showList(List<ItemChooserRow> list) {
         mProgressBar.setVisibility(View.GONE);
-        mStatus.setText(mLabels.mStatus);
 
-        if (list.isEmpty()) {
-            boolean showEmptyMessage = mItemAdapter.isEmpty();
-            mNotFoundMessage.setVisibility(
-                    showEmptyMessage ? View.VISIBLE : View.GONE);
-            mListView.setVisibility(showEmptyMessage ? View.GONE : View.VISIBLE);
-        } else {
-            mListView.setVisibility(View.VISIBLE);
+        if (!list.isEmpty()) {
             mItemAdapter.addAll(list);
         }
+        setState(State.PROGRESS_UPDATE_AVAILABLE);
     }
 
     /**
+     * Sets whether the item is enabled.
+     * @param id The id of the item to affect.
+     * @param enabled Whether the item should be enabled or not.
+     */
+    public void setEnabled(String id, boolean enabled) {
+        mItemAdapter.setEnabled(id, enabled);
+    }
+
+    /**
      * Clear all items from the dialog.
      */
     public void clear() {
         mItemAdapter.clear();
+        setState(State.STARTING);
+    }
+
+    /**
+     * Set the error state for the dialog.
+     */
+    public void setErrorState() {
+        setState(State.SHOWING_ERROR);
+    }
+
+    private void setState(State state) {
+        switch (state) {
+            case STARTING:
+                mStatus.setText(mLabels.mSearching);
+                mListView.setVisibility(View.GONE);
+                mProgressBar.setVisibility(View.VISIBLE);
+                break;
+            case SHOWING_ERROR:
+                mProgressBar.setVisibility(View.GONE);
+                mEmptyMessage.setText(mLabels.mErrorMessage);
+                mStatus.setText(mLabels.mErrorStatus);
+                break;
+            case PROGRESS_UPDATE_AVAILABLE:
+                mStatus.setText(mLabels.mStatus);
+                mProgressBar.setVisibility(View.GONE);
+                mListView.setVisibility(View.VISIBLE);
+
+                boolean showEmptyMessage = mItemAdapter.isEmpty();
+                mEmptyMessage.setText(mLabels.mNoneFound);
+                mEmptyMessage.setVisibility(showEmptyMessage ? View.VISIBLE : View.GONE);
+                break;
+        }
     }
 }