Add sample for XML-defined Adapters.

Change-Id: I31f4f93eeea0f0cac4485ce76d9188608567f071

samples/XmlAdapters/src/com/example/android/xmladapters/ContactPhotoBinder.java

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+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.xmladapters;
+
+import android.content.ContentUris;
+import android.content.Context;
+import android.content.res.Resources;
+import android.database.Cursor;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+import android.net.Uri;
+import android.provider.ContactsContract;
+import android.view.View;
+import android.widget.Adapters;
+import android.widget.TextView;
+
+import java.io.InputStream;
+import java.util.HashMap;
+
+/**
+ * This custom cursor binder is used by the adapter defined in res/xml to
+ * bin contacts photos to their respective list item. This binder simply
+ * queries a contact's photo based on the contact's id and sets the
+ * photo as a compound drawable on the TextView used to display the contact's
+ * name.
+ */
+public class ContactPhotoBinder extends Adapters.CursorBinder {
+    private static final int PHOTO_SIZE_DIP = 54;
+    
+    private final Drawable mDefault;
+    private final HashMap<Long, Drawable> mCache;
+    private final Resources mResources;
+    private final int mPhotoSize;
+
+    public ContactPhotoBinder(Context context, Adapters.CursorTransformation transformation) {
+        super(context, transformation);
+
+        mResources = mContext.getResources();
+        // Default picture used when a contact does not provide one
+        mDefault = mResources.getDrawable(R.drawable.ic_contact_picture);
+        // Cache used to avoid requerying contacts photos every time
+        mCache = new HashMap<Long, Drawable>();
+        // Compute the size of the photo based on the display's density
+        mPhotoSize = (int) (PHOTO_SIZE_DIP * mResources.getDisplayMetrics().density + 0.5f);
+    }
+
+    @Override
+    public boolean bind(View view, Cursor cursor, int columnIndex) {
+        final long id = cursor.getLong(columnIndex);
+        
+        // First check whether we have already cached the contact's photo
+        Drawable d = mCache.get(id);
+        
+        if (d == null) {
+            // If the photo wasn't in the cache, ask the contacts provider for
+            // an input stream we can use to load the photo
+            Uri uri = ContentUris.withAppendedId(ContactsContract.Contacts.CONTENT_URI, id);
+            InputStream stream = ContactsContract.Contacts.openContactPhotoInputStream(
+                    mContext.getContentResolver(), uri);
+    
+            // Creates the drawable for the contact's photo or use our fallback drawable
+            if (stream != null) {
+                Bitmap bitmap = BitmapFactory.decodeStream(stream);
+                d = new BitmapDrawable(mResources, bitmap);
+            } else {
+                d = mDefault;
+            }
+
+            d.setBounds(0, 0, mPhotoSize, mPhotoSize);
+            ((TextView) view).setCompoundDrawables(d, null, null, null);
+
+            // Remember the photo associated with this contact
+            mCache.put(id, d);
+        } else {
+            ((TextView) view).setCompoundDrawables(d, null, null, null);
+        }
+
+        return true;
+    }
+}

samples/XmlAdapters/src/com/example/android/xmladapters/ContactsListActivity.java

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+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.xmladapters;
+
+import android.app.ListActivity;
+import android.os.Bundle;
+
+/**
+ * This activity demonstrates how to create a complex UI using a ListView
+ * and an adapter defined in XML.
+ * 
+ * The following activity shows a list of contacts, their starred status
+ * and their photos, using the adapter defined in res/xml.
+ */
+public class ContactsListActivity extends ListActivity {
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.contacts_list);
+    }
+}