36.Android 自定义ContentProvider

36.Android 自定义ContentProvider

Android 自定义ContentProvider
ContentProvider 介绍

ContentProvider 优点

Android 自带的ContentProvider

ContentProvider Uri 结构

Google Uri 工具类

UriMatcher 解析

自定义 ContentProvider

ContentProvider 介绍

有一种情景：假如A应用存储的数据，B也用到。那么，要怎么共享数据呢？

其实有很多种解决办法，比如存在SD卡上、网络等等。

其实Android上的相册、联系人也都是Google给Android系统写的App。也提供了对应的一套API给我们调用到其相应的数据，这就是ContentProvider。

ContentProvider是获取数据和存储都用的是统一的封装接口，涉及到Uri的概念。

当然了，如果用到Uri了，我们可以使用Google提供的工具类 UriMatcher 和 ContentUris ，以下会讲到这些。

ContentProvider 优点

可以获取系统原生一些App的数据。

不同App之间可以共享数据。

对数据进行封装，存储和获取提供统一的API。

Android 自带的ContentProvider

如果想获取一些系统自带App的数据，可以参考：

android.provider

包下的ContentProvider。

ContentProvider Uri 结构

content://com.camnter.content.provider/message/6

content:// ：Scheme

com.camnter.content.provider ：Authority（主机名），这个ContentProvider的唯一标识。

message ：Table（表名）

6 ：Id

几个例子：

content://com.camnter.content.provider/message

：表示操作message表的所有记录。

content://com.camnter.content.provider/message/6

：表示操作message表的Id = 6的记录。

content://com.camnter.content.provider/message/6/content

：表示操作message表的Id = 6的记录的content字段。

Google Uri 工具类

UriMatcher ：

public void addURI(String authority, String path, int code)

：添加Uri，Uri会被添加到一个ArrayList里，提供

match(Uri uri)

去匹配。

public int match(Uri uri)

：根据Uri匹配改Uri是否被添加。

ContentUris：

public static long parseId(Uri contentUri)

：解析Uri取得Id。

public static Uri.Builder appendId(Uri.Builder builder, long id)

：添加Id。

public static Uri withAppendedId(Uri contentUri, long id)

：添加Id。

UriMatcher 解析

ContentUris的源码特别简单，整个类就调用了Uri类的两个方法 T T# 。

所以就看看UriMatcher源码吧。

由于对其他类的依赖不多，我就自定义了一份UriMatcher。

import android.net.Uri;

import java.util.ArrayList;
import java.util.List;

/**
Utility class to aid in matching URIs in content providers.

<p>To use this class, build up a tree of <code>UriMatcher</code> objects.
For example:
<pre>
private static final int PEOPLE = 1;
private static final int PEOPLE_ID = 2;
private static final int PEOPLE_PHONES = 3;
private static final int PEOPLE_PHONES_ID = 4;
private static final int PEOPLE_CONTACTMETHODS = 7;
private static final int PEOPLE_CONTACTMETHODS_ID = 8;

private static final int DELETED_PEOPLE = 20;

private static final int PHONES = 9;
private static final int PHONES_ID = 10;
private static final int PHONES_FILTER = 14;

private static final int CONTACTMETHODS = 18;
private static final int CONTACTMETHODS_ID = 19;

private static final int CALLS = 11;
private static final int CALLS_ID = 12;
private static final int CALLS_FILTER = 15;

private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);

static
{
sURIMatcher.addURI("contacts", "people", PEOPLE);
sURIMatcher.addURI("contacts", "people/#", PEOPLE_ID);
sURIMatcher.addURI("contacts", "people/#/phones", PEOPLE_PHONES);
sURIMatcher.addURI("contacts", "people/#/phones/#", PEOPLE_PHONES_ID);
sURIMatcher.addURI("contacts", "people/#/contact_methods", PEOPLE_CONTACTMETHODS);
sURIMatcher.addURI("contacts", "people/#/contact_methods/#", PEOPLE_CONTACTMETHODS_ID);
sURIMatcher.addURI("contacts", "deleted_people", DELETED_PEOPLE);
sURIMatcher.addURI("contacts", "phones", PHONES);
sURIMatcher.addURI("contacts", "phones/filter/*", PHONES_FILTER);
sURIMatcher.addURI("contacts", "phones/#", PHONES_ID);
sURIMatcher.addURI("contacts", "contact_methods", CONTACTMETHODS);
sURIMatcher.addURI("contacts", "contact_methods/#", CONTACTMETHODS_ID);
sURIMatcher.addURI("call_log", "calls", CALLS);
sURIMatcher.addURI("call_log", "calls/filter/*", CALLS_FILTER);
sURIMatcher.addURI("call_log", "calls/#", CALLS_ID);
}
</pre>
<p>Starting from API level {@link android.os.Build.VERSION_CODES#JELLY_BEAN_MR2}, paths can start
with a leading slash.  For example:
<pre>
sURIMatcher.addURI("contacts", "/people", PEOPLE);
</pre>
<p>Then when you need to match against a URI, call {@link #match}, providing
the URL that you have been given.  You can use the result to build a query,
return a type, insert or delete a row, or whatever you need, without duplicating
all of the if-else logic that you would otherwise need.  For example:
<pre>
public String getType(Uri url)
{
int match = sURIMatcher.match(url);
switch (match)
{
case PEOPLE:
return "vnd.android.cursor.dir/person";
case PEOPLE_ID:
return "vnd.android.cursor.item/person";
... snip ...
return "vnd.android.cursor.dir/snail-mail";
case PEOPLE_ADDRESS_ID:
return "vnd.android.cursor.item/snail-mail";
default:
return null;
}
}
</pre>
instead of:
<pre>
public String getType(Uri url)
{
List<String> pathSegments = url.getPathSegments();
if (pathSegments.size() >= 2) {
if ("people".equals(pathSegments.get(1))) {
if (pathSegments.size() == 2) {
return "vnd.android.cursor.dir/person";
} else if (pathSegments.size() == 3) {
return "vnd.android.cursor.item/person";
... snip ...
return "vnd.android.cursor.dir/snail-mail";
} else if (pathSegments.size() == 3) {
return "vnd.android.cursor.item/snail-mail";
}
}
}
return null;
}
</pre>
*/
public class UriMatcher
{
public static final int NO_MATCH = -1;
/**
* Creates the root node of the URI tree.
* 创建Uri树的根节点
*
* @param code the code to match for the root URI
*/
public UriMatcher(int code)
{
mCode = code;
mWhich = -1;
mChildren = new ArrayList<UriMatcher>();
mText = null;
}

private UriMatcher()
{
mCode = NO_MATCH;
mWhich = -1;
mChildren = new ArrayList<UriMatcher>();
mText = null;
}

/**
* Add a URI to match, and the code to return when this URI is
* matched. URI nodes may be exact match string, the token "*"
* that matches any text, or the token "#" that matches only
* numbers.
* 添加一个URI匹配，并且这里添加code值会在这个URI匹配成功的时候返回。URI节点可能精确匹配字符串，
* token为“*”的时候会匹配为text，token为“#”的时候只会匹配为数字
* <p>
* Starting from API level {@link android.os.Build.VERSION_CODES#JELLY_BEAN_MR2},
* this method will accept a leading slash in the path.
*
* @param authority the authority to match
*                  ContentProvider的authority
*
* @param path the path to match. * may be used as a wild card for
* any text, and # may be used as a wild card for numbers.
*             匹配路径，*可能是作为一个通配符用于任何文本,和#可能用作通配符数字。
*
* @param code the code that is returned when a URI is matched
* against the given components. Must be positive.
*             该URI匹配成功时返回的code
*/
public void addURI(String authority, String path, int code)
{
if (code < 0) {
throw new IllegalArgumentException("code " + code + " is invalid: it must be positive");
}

String[] tokens = null;
if (path != null) {
String newPath = path;
// Strip leading slash if present.
if (path.length() > 0 && path.charAt(0) == '/') {
newPath = path.substring(1);
}
tokens = newPath.split("/");
}

int numTokens = tokens != null ? tokens.length : 0;
UriMatcher node = this;
for (int i = -1; i < numTokens; i++) {
String token = i < 0 ? authority : tokens[i];
ArrayList<UriMatcher> children = node.mChildren;
int numChildren = children.size();
UriMatcher child;
int j;
for (j = 0; j < numChildren; j++) {
child = children.get(j);
if (token.equals(child.mText)) {
node = child;
break;
}
}
if (j == numChildren) {
// Child not found, create it
child = new UriMatcher();
if (token.equals("#")) {
child.mWhich = NUMBER;
} else if (token.equals("*")) {
child.mWhich = TEXT;
} else {
child.mWhich = EXACT;
}
child.mText = token;
node.mChildren.add(child);
node = child;
}
}
node.mCode = code;
}

/**
* Try to match against the path in a url.
* 尝试匹配一个url的路径。
*
* @param uri       The url whose path we will match against.
*                  将匹配的url路径。
*
* @return  The code for the matched node (added using addURI),
* or -1 if there is no matched node.
*          匹配节点设置的code（在使用addURI时，给对应URI设置code），
*          或者没有匹配节点，则反悔-1。
*/
public int match(Uri uri)
{
final List<String> pathSegments = uri.getPathSegments();
final int li = pathSegments.size();

UriMatcher node = this;

if (li == 0 && uri.getAuthority() == null) {
return this.mCode;
}

for (int i=-1; i<li; i++) {
String u = i < 0 ? uri.getAuthority() : pathSegments.get(i);
ArrayList<UriMatcher> list = node.mChildren;
if (list == null) {
break;
}
node = null;
int lj = list.size();
for (int j=0; j<lj; j++) {
UriMatcher n = list.get(j);
which_switch:
switch (n.mWhich) {
case EXACT:
if (n.mText.equals(u)) {
node = n;
}
break;
case NUMBER:
int lk = u.length();
for (int k=0; k<lk; k++) {
char c = u.charAt(k);
if (c < '0' || c > '9') {
break which_switch;
}
}
node = n;
break;
case TEXT:
node = n;
break;
}
if (node != null) {
break;
}
}
if (node == null) {
return NO_MATCH;
}
}

return node.mCode;
}

private static final int EXACT = 0;
private static final int NUMBER = 1;
private static final int TEXT = 2;

private int mCode;
private int mWhich;
private String mText;
private ArrayList<UriMatcher> mChildren;
}

以上注释还有使用，Google告诉我们怎么使用UriMatcher的范例代码。

自定义 ContentProvider

代码都重复看过，都写上了注释。

BaseContentProvider

public abstract class BaseContentProvider extends ContentProvider {

// 单一数据的MIME类型字符串应该以vnd.android.cursor.item/开头
protected static final String MIME_SINGLE = "vnd.android.cursor.item/";

// 数据集的MIME类型字符串则应该以vnd.android.cursor.dir/开头
protected static final String MIME_MULTIPLE = "vnd.android.cursor.dir/";

/**
* Implement this to initialize your content provider on startup.
* This method is called for all registered content providers on the
* application main thread at application launch time.  It must not perform
* lengthy operations, or application startup will be delayed.
* <p/>
* <p>You should defer nontrivial initialization (such as opening,
* upgrading, and scanning databases) until the content provider is used
* (via {@link #query}, {@link #insert}, etc).  Deferred initialization
* keeps application startup fast, avoids unnecessary work if the provider
* turns out not to be needed, and stops database errors (such as a full
* disk) from halting application launch.
* <p/>
* <p>If you use SQLite, {@link SQLiteOpenHelper}
* is a helpful utility class that makes it easy to manage databases,
* and will automatically defer opening until first use.  If you do use
* SQLiteOpenHelper, make sure to avoid calling
* {@link SQLiteOpenHelper#getReadableDatabase} or
* {@link SQLiteOpenHelper#getWritableDatabase}
* from this method.  (Instead, override
* {@link SQLiteOpenHelper#onOpen} to initialize the
* database when it is first opened.)
*
* @return true if the provider was successfully loaded, false otherwise
*/
@Override
public abstract boolean onCreate();

/**
* Implement this to handle query requests from clients.
* This method can be called from multiple threads, as described in
* <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html#Threads">Processes
* and Threads</a>.
* <p/>
* Example client call:<p>
* <pre>// Request a specific record.
* Cursor managedCursor = managedQuery(
* ContentUris.withAppendedId(Contacts.People.CONTENT_URI, 2),
* projection,    // Which columns to return.
* null,          // WHERE clause.
* null,          // WHERE clause value substitution
* People.NAME + " ASC");   // Sort order.</pre>
* Example implementation:<p>
* <pre>// SQLiteQueryBuilder is a helper class that creates the
* // proper SQL syntax for us.
* SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder();
* <p/>
* // Set the table we're querying.
* qBuilder.setTables(DATABASE_TABLE_NAME);
* <p/>
* // If the query ends in a specific record number, we're
* // being asked for a specific record, so set the
* // WHERE clause in our query.
* if((URI_MATCHER.match(uri)) == SPECIFIC_MESSAGE){
* qBuilder.appendWhere("_id=" + uri.getPathLeafId());
* }
* <p/>
* // Make the query.
* Cursor c = qBuilder.query(mDb,
* projection,
* selection,
* selectionArgs,
* groupBy,
* having,
* sortOrder);
* c.setNotificationUri(getContext().getContentResolver(), uri);
* return c;</pre>
*
* @param uri           The URI to query. This will be the full URI sent by the client;
*                      if the client is requesting a specific record, the URI will end in a record number
*                      that the implementation should parse and add to a WHERE or HAVING clause, specifying
*                      that _id value.
* @param projection    The list of columns to put into the cursor. If
*                      {@code null} all columns are included.
* @param selection     A selection criteria to apply when filtering rows.
*                      If {@code null} then all rows are included.
* @param selectionArgs You may include ?s in selection, which will be replaced by
*                      the values from selectionArgs, in order that they appear in the selection.
*                      The values will be bound as Strings.
* @param sortOrder     How the rows in the cursor should be sorted.
*                      If {@code null} then the provider is free to define the sort order.
* @return a Cursor or {@code null}.
*/
@Override
public abstract Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder);

/**
* Implement this to handle requests for the MIME type of the data at the
* given URI.  The returned MIME type should start with
* <code>vnd.android.cursor.item</code> for a single record,
* or <code>vnd.android.cursor.dir/</code> for multiple items.
* This method can be called from multiple threads, as described in
* <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html#Threads">Processes
* and Threads</a>.
* <p/>
* <p>Note that there are no permissions needed for an application to
* access this information; if your content provider requires read and/or
* write permissions, or is not exported, all applications can still call
* this method regardless of their access permissions.  This allows them
* to retrieve the MIME type for a URI when dispatching intents.
*
* @param uri the URI to query.
* @return a MIME type string, or {@code null} if there is no type.
*/
@Override
public abstract String getType(Uri uri);

/**
* Implement this to handle requests to insert a new row.
* As a courtesy, call {@link ContentResolver#notifyChange(Uri, ContentObserver) notifyChange()}
* after inserting.
* This method can be called from multiple threads, as described in
* <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html#Threads">Processes
* and Threads</a>.
*
* @param uri    The content:// URI of the insertion request. This must not be {@code null}.
* @param values A set of column_name/value pairs to add to the database.
*               This must not be {@code null}.
* @return The URI for the newly inserted item.
*/
@Override
public abstract Uri insert(Uri uri, ContentValues values);

/**
* Implement this to handle requests to delete one or more rows.
* The implementation should apply the selection clause when performing
* deletion, allowing the operation to affect multiple rows in a directory.
* As a courtesy, call {@link ContentResolver#notifyChange(Uri, ContentObserver) notifyChange()}
* after deleting.
* This method can be called from multiple threads, as described in
* <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html#Threads">Processes
* and Threads</a>.
* <p/>
* <p>The implementation is responsible for parsing out a row ID at the end
* of the URI, if a specific row is being deleted. That is, the client would
* pass in <code>content://contacts/people/22</code> and the implementation is
* responsible for parsing the record number (22) when creating a SQL statement.
*
* @param uri           The full URI to query, including a row ID (if a specific record is requested).
* @param selection     An optional restriction to apply to rows when deleting.
* @param selectionArgs
* @return The number of rows affected.
* @throws SQLException
*/
@Override
public abstract int delete(Uri uri, String selection, String[] selectionArgs);

/**
* Implement this to handle requests to update one or more rows.
* The implementation should update all rows matching the selection
* to set the columns according to the provided values map.
* As a courtesy, call {@link ContentResolver#notifyChange(Uri, ContentObserver) notifyChange()}
* after updating.
* This method can be called from multiple threads, as described in
* <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html#Threads">Processes
* and Threads</a>.
*
* @param uri           The URI to query. This can potentially have a record ID if this
*                      is an update request for a specific record.
* @param values        A set of column_name/value pairs to update in the database.
*                      This must not be {@code null}.
* @param selection     An optional filter to match rows to update.
* @param selectionArgs
* @return the number of rows affected.
*/
@Override
public abstract int update(Uri uri, ContentValues values, String selection, String[] selectionArgs);

}

MessageSQLiteHelper

public class MessageSQLiteHelper extends SQLiteOpenHelper {

private static final String TAG = "MessageSQLiteHelper";

private static final String DB_NAME = "message.db";
private static final int VERSION = 1;

public static final String TB_MESSAGE = "tb_message";
public static final String TB_MESSAGE_SQL = "CREATE TABLE IF NOT EXISTS " + TB_MESSAGE + "(_id  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT," +
" content text)";

private static MessageSQLiteHelper ourInstance;

public MessageSQLiteHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
}

public static MessageSQLiteHelper getInstance(Context context) {
if (ourInstance == null) ourInstance = new MessageSQLiteHelper(context);
return ourInstance;
}

public MessageSQLiteHelper(Context context) {
this(context, DB_NAME, null, VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(TB_MESSAGE_SQL);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.i(TAG, "onUpgrade");
}

}

MessageContentProvider

public class MessageContentProvider extends BaseContentProvider {

// 主机名
private static final String AUTHORITY = "com.camnter.content.provider";

// Message uri
public static final Uri MESSAGE_URI = Uri.parse("content://" + AUTHORITY + "/message");

// 数据集的MIME类型字符串则应该以vnd.android.cursor.dir/开头
private static final String TOPIC_SINGLE = MIME_SINGLE + "message";

// 单一数据的MIME类型字符串应该以vnd.android.cursor.item/开头
private static final String TOPIC_MULTIPLE = MIME_MULTIPLE + "message";

// 有id匹配码
private static final int MESSAGE = 6;
// 有无匹配码
public static final int MESSAGES = 7;

// Message SQLite helper
private MessageSQLiteHelper messageSQLiteHelper;

private static final UriMatcher messageUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

static {
// content://com.camnter.content.provider/message
messageUriMatcher.addURI(AUTHORITY, "message", MESSAGES);
// content://com.camnter.content.provider/message/#
messageUriMatcher.addURI(AUTHORITY, "message/#", MESSAGE);
}

@Override
public boolean onCreate() {
this.messageSQLiteHelper = MessageSQLiteHelper.getInstance(this.getContext());
return true;
}

@Override
public String getType(Uri uri) {
int match = messageUriMatcher.match(uri);
switch (match) {
case MESSAGE:
return TOPIC_SINGLE;
case MESSAGES:
return TOPIC_MULTIPLE;
default:
return null;
}
}

@Override
public Uri insert(Uri uri, ContentValues values) {
SQLiteDatabase db = this.messageSQLiteHelper.getWritableDatabase();
long id;
switch (messageUriMatcher.match(uri)) {
case MESSAGE:
id = db.insert(MessageSQLiteHelper.TB_MESSAGE, "content", values);
this.getContext().getContentResolver().notifyChange(uri, null);
return ContentUris.withAppendedId(uri, id);
case MESSAGES:
id = db.insert(MessageSQLiteHelper.TB_MESSAGE, "content", values);
String path = uri.toString();
this.getContext().getContentResolver().notifyChange(uri, null);
// 新id的Uri替换旧id的Uri
return Uri.parse(path.substring(0, path.lastIndexOf("/")) +"/"+ id);
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
}

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
SQLiteDatabase db = this.messageSQLiteHelper.getWritableDatabase();
int count;
switch (messageUriMatcher.match(uri)) {
case MESSAGE:
count = db.delete(MessageSQLiteHelper.TB_MESSAGE, selection, selectionArgs);
this.getContext().getContentResolver().notifyChange(uri, null);
break;
case MESSAGES:
long messageId = ContentUris.parseId(uri);
// 指定id
String where = "_id=" + messageId;
// 把其它条件附加上
where += !TextUtils.isEmpty(selection) ? " and (" + selection + ")" : "";
count = db.delete(MessageSQLiteHelper.TB_MESSAGE, where, selectionArgs);
this.getContext().getContentResolver().notifyChange(uri, null);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
return count;
}

@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
SQLiteDatabase db = this.messageSQLiteHelper.getWritableDatabase();
int count;
switch (messageUriMatcher.match(uri)) {
case MESSAGE:
long messageId = ContentUris.parseId(uri);
// 指定id
String where = "_id=" + messageId;
// 把其它条件附加上
where += !TextUtils.isEmpty(selection) ? " and (" + selection + ")" : "";
count = db.update(MessageSQLiteHelper.TB_MESSAGE, values, where, selectionArgs);
this.getContext().getContentResolver().notifyChange(uri, null);
break;
case MESSAGES:
count = db.update(MessageSQLiteHelper.TB_MESSAGE, values, selection, selectionArgs);
this.getContext().getContentResolver().notifyChange(uri, null);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
return count;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteDatabase db = this.messageSQLiteHelper.getReadableDatabase();
Cursor cursor;
switch (messageUriMatcher.match(uri)) {
case MESSAGE:
long messageId = ContentUris.parseId(uri);
// 指定id
String where = "_id=" + messageId;
// 把其它条件附加上
where += !TextUtils.isEmpty(selection) ? " and (" + selection + ")" : "";
cursor = db.query(MessageSQLiteHelper.TB_MESSAGE, projection, where, selectionArgs, null, null, sortOrder);
this.getContext().getContentResolver().notifyChange(uri, null);
return cursor;
case MESSAGES:
cursor = db.query(MessageSQLiteHelper.TB_MESSAGE, projection, selection, selectionArgs, null, null, sortOrder);
this.getContext().getContentResolver().notifyChange(uri, null);
return cursor;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
}

}

CustomContentProviderActivity

public class CustomContentProviderActivity extends AppCompatActivity {

private RecyclerView providerRV;
private ProviderRecyclerViewAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.activity_custom_content_provider);

this.getContentResolver().registerContentObserver(MessageContentProvider.MESSAGE_URI, true, new MessageProviderObserver(new Handler()));

this.providerRV = (RecyclerView) this.findViewById(R.id.provider_rv);
this.adapter = new ProviderRecyclerViewAdapter(this.getContentResolver(), MessageContentProvider.MESSAGE_URI);
this.providerRV.setAdapter(this.adapter);
this.initRecyclerView();
}

private void initRecyclerView() {
// 实例化LinearLayoutManager
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
// 设置垂直布局
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);

// 设置布局管理器
this.providerRV.setLayoutManager(linearLayoutManager);

this.providerRV.setItemAnimator(new DefaultItemAnimator());
this.providerRV.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));

// 使RecyclerView保持固定的大小，该信息被用于自身的优化
this.providerRV.setHasFixedSize(true);

ArrayList<SQLiteData> allData = new ArrayList<>();
allData.add(new SQLiteData());
this.adapter.setList(allData);
this.adapter.notifyDataSetChanged();
}

private class MessageProviderObserver extends ContentObserver {

/**
* Creates a content observer.
*
* @param handler The handler to run {@link #onChange} on, or null if none.
*/
public MessageProviderObserver(Handler handler) {
super(handler);
}

@Override
public void onChange(boolean selfChange, Uri uri) {
super.onChange(selfChange, uri);
}
}

/**
* Provider RecyclerView Adapter
*/
private class ProviderRecyclerViewAdapter extends EasyRecyclerViewAdapter implements View.OnClickListener {

private static final int ITEM_PROVIDER_OPERATION = 0;
private static final int ITEM_PROVIDER_DATA = 1;

private ContentResolver resolver;
private Uri uri;

public ProviderRecyclerViewAdapter(ContentResolver resolver, Uri uri) {
this.resolver = resolver;
this.uri = uri;
}

@Override
public int[] getItemLayouts() {
return new int[]{R.layout.item_content_provider_operation, R.layout.item_content_provider_data};
}

@Override
public void onBindRecycleViewHolder(EasyRecyclerViewHolder easyRecyclerViewHolder, int position) {
int itemType = this.getRecycleViewItemType(position);
switch (itemType) {
case ITEM_PROVIDER_OPERATION:
easyRecyclerViewHolder.findViewById(R.id.provider_add_bt).setOnClickListener(this);
easyRecyclerViewHolder.findViewById(R.id.provider_del_bt).setOnClickListener(this);
easyRecyclerViewHolder.findViewById(R.id.provider_mod_bt).setOnClickListener(this);
easyRecyclerViewHolder.findViewById(R.id.provider_query_bt).setOnClickListener(this);
break;
case ITEM_PROVIDER_DATA:
ProviderData data = (ProviderData) this.getList().get(position);
TextView idTV = easyRecyclerViewHolder.findViewById(R.id.provider_id_tv);
TextView contentTV = easyRecyclerViewHolder.findViewById(R.id.provider_content_tv);
idTV.setText(data.id + "");
contentTV.setText(data.content + "");
break;
}
}

@Override
public int getRecycleViewItemType(int i) {
if (i == 0) {
return ITEM_PROVIDER_OPERATION;
} else {
return ITEM_PROVIDER_DATA;
}
}

/**
* Called when a view has been clicked.
*
* @param v The view that was clicked.
*/
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.provider_add_bt: {
ContentValues values = new ContentValues();
values.put("content", "Save you from anything");
this.resolver.insert(this.uri, values);
this.refresh();
break;
}
case R.id.provider_del_bt: {
this.resolver.delete(this.uri, null, null);
this.refresh();
break;
}
case R.id.provider_mod_bt: {
List<ProviderData> allData = this.queryAll();
int firstId = allData.get(0).id;
ContentValues values = new ContentValues();
values.put("content", UUID.randomUUID().toString());
String path = this.uri.toString();
this.resolver.update(Uri.parse(path.substring(0, path.lastIndexOf("/")) +"/message/"+ firstId), values, null, null);
this.refresh();
break;
}
case R.id.provider_query_bt: {
this.refresh();
break;
}
}
}

private void refresh() {
List<ProviderData> l = this.queryAll();
l.add(0,new ProviderData());
this.setList(l);
this.notifyDataSetChanged();
}

private List<ProviderData> queryAll() {
List<ProviderData> allData = new ArrayList<>();
Cursor result = this.resolver.query(this.uri, null, null, null, null);
for (result.moveToFirst(); !result.isAfterLast(); result.moveToNext()) {
ProviderData data = new ProviderData();
data.id = result.getInt(result.getColumnIndex("_id"));
data.content = result.getString(result.getColumnIndex("content"));
allData.add(data);
}
result.close();
return allData;
}

}

}