快速联系人标记到底是什么？废话不多说，直接上图：
简单的说，就是将 QuickContactBadge 这个控件和联系人信息绑定起来，以达到点击相应联系人头像时，弹出一个 Dialog，在此 Dialog 中显示当前联系人的相关信息，同时这里的每一个信息又都是可点击的，点击之后，系统会自动匹配可以响应的 App，示例中点击了邮箱地址之后直接跳到创建新邮件界面。除此之外，点击此 Dialog 的标题栏，会直接跳到联系人详情界面。接下来，让我们看看此功能是什么实现的。
一、界面组成及原理介绍
从效果图中，我们不难看出，界面的组成相当简单：一个 ListView，一个 Dialog。ListView 中每一个 Item 中包含一个 ImageView 和 一个 TextView；Dialog 中是一个 ViewPager，ViewPager 的每一个界面元素是不同的联系人信息。
表面上看，大概就是这个样子，但实际上，有一个地方是不对的，那就是 ListView 中的每一个 Item 布局中的图片显示控件用的不是 ImageView，而是 QuickContactBadge。QuickContactBadge 是个什么鬼？想必很多人直接懵逼了，但如果我把这个控件指给你，你一定会骂娘的……
没错，就是这货！
可别小看了这个控件的功能，就是因为有了它，我们才可以省去很多工作（关联此图片对应的联系人、填充 ViewPager 每个页面的数据并决定用可以响应不同点击事件的 App，blabla……）。
QuickContactBadge 中有两个函数十分关键：
1.assignContactUri
指定关联的联系人信息
2.setImageBitmap
指定 QuickContactBadge 显示的图片资源
知道了这些之后，其实实现起来也就没什么难度了，无非就两件事：
1.获取联系人数据
2.将 QuickContactBadge 和相应的联系人数据绑定起来
二、实现
1.获取联系人数据
本例中，是通过查询匹配用户名信息的方法获取联系人列表的，主要涉及到的的知识有：
- LoaderManager.LoaderCallbacks（查询 Contact Provider 数据）
- CursorAdapter （显示 LoaderManager.LoaderCallbacks 查询到的数据）
ListView 中 Item 的布局文件
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="@dimen/padding_small">
<QuickContactBadge
android:id="@+id/quick_contact"
android:layout_width="@dimen/padding_item"
android:layout_height="@dimen/padding_item"
android:scaleType="centerCrop" />
<TextView
android:id="@+id/display_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="@dimen/padding_medium"
android:layout_toRightOf="@+id/quick_contact"
android:text="@string/null_value"
android:textSize="@dimen/font_small" />
</RelativeLayout>自定义 ContactsAdapter 继承自 CursorAdapter
private class ContactsAdapter extends CursorAdapter {
private LayoutInflater mInflater;
public ContactsAdapter(Context context) {
super(context, null, 0);
/*
* Gets an inflater that can instantiate
* the ListView layout from the file.
*/
mInflater = LayoutInflater.from(context);
}
/**
* Defines a class that hold resource IDs of each item layout
* row to prevent having to look them up each time data is
* bound to a row.
*/
private class ViewHolder {
TextView displayName;
QuickContactBadge quickContact;
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup viewGroup) {
/* Inflates the item layout. Stores resource IDs in a
* in a ViewHolder class to prevent having to look
* them up each time bindView() is called.
*/
final ViewHolder viewHolder;
View itemView = null;
if(itemView == null){
itemView = mInflater.inflate(R.layout.item_display_quick_contact_badge, viewGroup, false);
viewHolder = new ViewHolder();
viewHolder.displayName = (TextView) itemView.findViewById(R.id.display_name);
viewHolder.quickContact = (QuickContactBadge) itemView.findViewById(R.id.quick_contact);
itemView.setTag(viewHolder);
}else{
viewHolder = (ViewHolder) itemView.getTag();
}
return itemView;
}
/**
* Des: 将数据源绑定到视图
*
* 由 bindView 方法调用的次数可以知道：在此处不用迭代 cursor，因为每一次 Android Framework 都为我们做好了
*
* Time: 2017/6/6 下午6:55
*/
@Override
public void bindView(View view, Context context, Cursor cursor) {
final ViewHolder holder = (ViewHolder) view.getTag();
final String displayName = cursor.getString(mDisplayNameIndex);
final String photoData = cursor.getString(mPhotoDataIndex);
// Sets the display name in the layout
holder.displayName.setText(displayName);
/*
* Generates a contact URI for the QuickContactBadge.
*/
final Uri contactUri = Contacts.getLookupUri(cursor.getLong(mIdIndex), cursor.getString(mLookupKeyIndex));
holder.quickContact.assignContactUri(contactUri);
/*
* Decodes the thumbnail file to a Bitmap.
* The method loadContactPhotoThumbnail() is defined
* in the section "Set the Contact URI and Thumbnail"
*/
Bitmap thumbnailBitmap = null;
if(!TextUtils.isEmpty(photoData)){
thumbnailBitmap = loadContactPhotoThumbnail(photoData);
}else{
thumbnailBitmap = BitmapFactory.decodeResource(getResources(),R.mipmap.ic_launcher);
}
/*
* Sets the image in the QuickContactBadge
* QuickContactBadge inherits from ImageView
*/
holder.quickContact.setImageBitmap(thumbnailBitmap);
}
/**
* Load a contact photo thumbnail and return it as a Bitmap,
* resizing the image to the provided image dimensions as needed.
* @param photoData photo ID Prior to Honeycomb, the contact's _ID value.
* For Honeycomb and later, the value of PHOTO_THUMBNAIL_URI.
* @return A thumbnail Bitmap, sized to the provided width and height.
* Returns null if the thumbnail is not found.
*/
private Bitmap loadContactPhotoThumbnail(String photoData) {
// Creates an asset file descriptor for the thumbnail file.
AssetFileDescriptor afd = null;
// try-catch block for file not found
try {
// Creates a holder for the URI.
Uri thumbUri;
// If Android 3.0 or later
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
// Sets the URI from the incoming PHOTO_THUMBNAIL_URI
thumbUri = Uri.parse(photoData);
} else {
// Prior to Android 3.0, constructs a photo Uri using _ID
/*
* Creates a contact URI from the Contacts content URI
* incoming photoData (_ID)
*/
final Uri contactUri = Uri.withAppendedPath(Contacts.CONTENT_URI, photoData);
/*
* Creates a photo URI by appending the content URI of
* Contacts.Photo.
*/
thumbUri = Uri.withAppendedPath(contactUri, Contacts.Photo.CONTENT_DIRECTORY);
}
/*
* Retrieves an AssetFileDescriptor object for the thumbnail
* URI
* using ContentResolver.openAssetFileDescriptor
*/
afd = DisplayingQuickContactBadgeActivity.this.getContentResolver().openAssetFileDescriptor(thumbUri, "r");
/*
* Gets a file descriptor from the asset file descriptor.
* This object can be used across processes.
*/
FileDescriptor fileDescriptor = afd.getFileDescriptor();
// Decode the photo file and return the result as a Bitmap
// If the file descriptor is valid
if (fileDescriptor != null) {
// Decodes the bitmap
return BitmapFactory.decodeFileDescriptor(fileDescriptor, null, null);
}
// If the file isn't found
} catch (FileNotFoundException e) {
/*
* Handle file not found errors
*/
// In all cases, close the asset file descriptor
} finally {
if (afd != null) {
try {
afd.close();
} catch (IOException e) {}
}
}
return null;
}
}实现 LoaderManager.LoaderCallbacks 接口,并定义查询条件
public class DisplayingQuickContactBadgeActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor>{
...
/*
* Defines a projection based on platform version. This ensures
* that you retrieve the correct columns.
*/
private static final String[] PROJECTION =
{
ContactsContract.Contacts._ID,
Contacts.LOOKUP_KEY,
(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) ? Contacts.DISPLAY_NAME_PRIMARY : Contacts.DISPLAY_NAME,
(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) ? Contacts.PHOTO_THUMBNAIL_URI : Contacts._ID
/*
* Although it's not necessary to include the
* column twice, this keeps the number of
* columns the same regardless of version
*/
};
// Defines the text expression
@SuppressLint("InlinedApi")
private static final String SELECTION =
Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
ContactsContract.Contacts.DISPLAY_NAME_PRIMARY + " LIKE ?" :
ContactsContract.Contacts.DISPLAY_NAME + " LIKE ?";
// Defines a variable for the search string
private String mSearchString = "张";
// Defines the array to hold values that replace the ?
private String[] mSelectionArgs = { mSearchString };
/*
* As a shortcut, defines constants for the
* column indexes in the Cursor. The index is
* 0-based and always matches the column order
* in the projection.
*/
// Column index of the _ID column
private int mIdIndex = 0;
// Column index of the LOOKUP_KEY column
private int mLookupKeyIndex = 1;
// Column index of the display name column
private int mDisplayNameIndex = 2;
/*
* Column index of the photo data column.
* It's PHOTO_THUMBNAIL_URI for Honeycomb and later,
* and _ID for previous versions.
*/
private int mPhotoDataIndex = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ? 3 : 0;
...
//以下是实现 LoaderManager.LoaderCallbacks<Cursor> 接口必须实现的三个方法
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
/*
* Makes search string into pattern and
* stores it in the selection array
*/
mSelectionArgs[0] = "%" + mSearchString + "%";
// Starts the query
return new CursorLoader(
this,
ContactsContract.Contacts.CONTENT_URI,
PROJECTION,
SELECTION,
mSelectionArgs,
null
);
}
@Override
public void onLoadFinished(android.content.Loader<Cursor> loader, Cursor data) {
// Put the result Cursor in the adapter for the ListView
mAdapter.swapCursor(data);
}
@Override
public void onLoaderReset(android.content.Loader<Cursor> loader) {
// Delete the reference to the existing Cursor
mAdapter.swapCursor(null);
}
...
}将 ListView 和自定义 ContactsAdapter 关联起来并开始查询数据
...
// Defines a ListView
private ListView mListView;
// Defines a ContactsAdapter
private ContactsAdapter mAdapter;
...
mAdapter = new ContactsAdapter(this);
// Sets up the adapter for the ListView
mListView.setAdapter(mAdapter);
// Initializes the loader
// 开始查询
getLoaderManager().initLoader(0, null, this);2.在适配器中将 QuickContactBadge 和查询到的数据关联起来
...
holder.quickContact.assignContactUri(contactUri);
holder.quickContact.setImageBitmap(thumbnailBitmap);
...我们需要做的就这么多，最近实现有点忙，文章没有经过好好整理，见谅，最后，将完整代码贴出（其实就一个 Activity）
public class DisplayingQuickContactBadgeActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor>{
// Defines a ListView
private ListView mListView;
// Defines a ContactsAdapter
private ContactsAdapter mAdapter;
/*
* Defines a projection based on platform version. This ensures
* that you retrieve the correct columns.
*/
private static final String[] PROJECTION =
{
ContactsContract.Contacts._ID,
Contacts.LOOKUP_KEY,
(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) ? Contacts.DISPLAY_NAME_PRIMARY : Contacts.DISPLAY_NAME,
(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) ? Contacts.PHOTO_THUMBNAIL_URI : Contacts._ID
/*
* Although it's not necessary to include the
* column twice, this keeps the number of
* columns the same regardless of version
*/
};
// Defines the text expression
@SuppressLint("InlinedApi")
private static final String SELECTION =
Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
ContactsContract.Contacts.DISPLAY_NAME_PRIMARY + " LIKE ?" :
ContactsContract.Contacts.DISPLAY_NAME + " LIKE ?";
// Defines a variable for the search string
private String mSearchString = "张";
// Defines the array to hold values that replace the ?
private String[] mSelectionArgs = { mSearchString };
/*
* As a shortcut, defines constants for the
* column indexes in the Cursor. The index is
* 0-based and always matches the column order
* in the projection.
*/
// Column index of the _ID column
private int mIdIndex = 0;
// Column index of the LOOKUP_KEY column
private int mLookupKeyIndex = 1;
// Column index of the display name column
private int mDisplayNameIndex = 2;
/*
* Column index of the photo data column.
* It's PHOTO_THUMBNAIL_URI for Honeycomb and later,
* and _ID for previous versions.
*/
private int mPhotoDataIndex = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ? 3 : 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
}
private void initView(){
mListView = (ListView)this.findViewById(R.id.lv);
}
private void initData(){
mAdapter = new ContactsAdapter(this);
// Sets up the adapter for the ListView
mListView.setAdapter(mAdapter);
// Initializes the loader
getLoaderManager().initLoader(0, null, this);
}
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
/*
* Makes search string into pattern and
* stores it in the selection array
*/
mSelectionArgs[0] = "%" + mSearchString + "%";
// Starts the query
return new CursorLoader(
this,
ContactsContract.Contacts.CONTENT_URI,
PROJECTION,
SELECTION,
mSelectionArgs,
null
);
}
@Override
public void onLoadFinished(android.content.Loader<Cursor> loader, Cursor data) {
// Put the result Cursor in the adapter for the ListView
mAdapter.swapCursor(data);
}
@Override
public void onLoaderReset(android.content.Loader<Cursor> loader) {
// Delete the reference to the existing Cursor
mAdapter.swapCursor(null);
}
private class ContactsAdapter extends CursorAdapter {
private LayoutInflater mInflater;
public ContactsAdapter(Context context) {
super(context, null, 0);
/*
* Gets an inflater that can instantiate
* the ListView layout from the file.
*/
mInflater = LayoutInflater.from(context);
}
/**
* Defines a class that hold resource IDs of each item layout
* row to prevent having to look them up each time data is
* bound to a row.
*/
private class ViewHolder {
TextView displayName;
QuickContactBadge quickContact;
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup viewGroup) {
/* Inflates the item layout. Stores resource IDs in a
* in a ViewHolder class to prevent having to look
* them up each time bindView() is called.
*/
final ViewHolder viewHolder;
View itemView = null;
if(itemView == null){
itemView = mInflater.inflate(R.layout.item_display_quick_contact_badge, viewGroup, false);
viewHolder = new ViewHolder();
viewHolder.displayName = (TextView) itemView.findViewById(R.id.display_name);
viewHolder.quickContact = (QuickContactBadge) itemView.findViewById(R.id.quick_contact);
itemView.setTag(viewHolder);
}else{
viewHolder = (ViewHolder) itemView.getTag();
}
return itemView;
}
/**
* Des: 将数据源绑定到视图
*
* 由 bindView 方法调用的次数可以知道：在此处不用迭代 cursor，因为每一次 Android Framework 都为我们做好了
*
* Time: 2017/6/6 下午6:55
*/
@Override
public void bindView(View view, Context context, Cursor cursor) {
final ViewHolder holder = (ViewHolder) view.getTag();
final String displayName = cursor.getString(mDisplayNameIndex);
final String photoData = cursor.getString(mPhotoDataIndex);
// Sets the display name in the layout
holder.displayName.setText(displayName);
/*
* Generates a contact URI for the QuickContactBadge.
*/
final Uri contactUri = Contacts.getLookupUri(cursor.getLong(mIdIndex), cursor.getString(mLookupKeyIndex));
holder.quickContact.assignContactUri(contactUri);
/*
* Decodes the thumbnail file to a Bitmap.
* The method loadContactPhotoThumbnail() is defined
* in the section "Set the Contact URI and Thumbnail"
*/
Bitmap thumbnailBitmap = null;
if(!TextUtils.isEmpty(photoData)){
thumbnailBitmap = loadContactPhotoThumbnail(photoData);
}else{
thumbnailBitmap = BitmapFactory.decodeResource(getResources(),R.mipmap.ic_launcher);
}
/*
* Sets the image in the QuickContactBadge
* QuickContactBadge inherits from ImageView
*/
holder.quickContact.setImageBitmap(thumbnailBitmap);
}
/**
* Load a contact photo thumbnail and return it as a Bitmap,
* resizing the image to the provided image dimensions as needed.
* @param photoData photo ID Prior to Honeycomb, the contact's _ID value.
* For Honeycomb and later, the value of PHOTO_THUMBNAIL_URI.
* @return A thumbnail Bitmap, sized to the provided width and height.
* Returns null if the thumbnail is not found.
*/
private Bitmap loadContactPhotoThumbnail(String photoData) {
// Creates an asset file descriptor for the thumbnail file.
AssetFileDescriptor afd = null;
// try-catch block for file not found
try {
// Creates a holder for the URI.
Uri thumbUri;
// If Android 3.0 or later
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
// Sets the URI from the incoming PHOTO_THUMBNAIL_URI
thumbUri = Uri.parse(photoData);
} else {
// Prior to Android 3.0, constructs a photo Uri using _ID
/*
* Creates a contact URI from the Contacts content URI
* incoming photoData (_ID)
*/
final Uri contactUri = Uri.withAppendedPath(Contacts.CONTENT_URI, photoData);
/*
* Creates a photo URI by appending the content URI of
* Contacts.Photo.
*/
thumbUri = Uri.withAppendedPath(contactUri, Contacts.Photo.CONTENT_DIRECTORY);
}
/*
* Retrieves an AssetFileDescriptor object for the thumbnail
* URI
* using ContentResolver.openAssetFileDescriptor
*/
afd = DisplayingQuickContactBadgeActivity.this.getContentResolver().openAssetFileDescriptor(thumbUri, "r");
/*
* Gets a file descriptor from the asset file descriptor.
* This object can be used across processes.
*/
FileDescriptor fileDescriptor = afd.getFileDescriptor();
// Decode the photo file and return the result as a Bitmap
// If the file descriptor is valid
if (fileDescriptor != null) {
// Decodes the bitmap
return BitmapFactory.decodeFileDescriptor(fileDescriptor, null, null);
}
// If the file isn't found
} catch (FileNotFoundException e) {
/*
* Handle file not found errors
*/
// In all cases, close the asset file descriptor
} finally {
if (afd != null) {
try {
afd.close();
} catch (IOException e) {}
}
}
return null;
}
}
}三、心得
每一个知识点都有最少必要知识，找出最少必要知识才是解决问题的关键。