36.Android 自定義ContentProvider
ContentProvider 介紹
有一種情景：假如A應用存儲的數據，B也用到。那麼，要怎麼共享數據呢？
其實有很多種解決辦法，比如存在SD卡上、網絡等等。
其實Android上的相冊、聯繫人也都是Google給Android系統寫的App。也提供了對應的一套API給我們調用到其相應的數據，這就是ContentProvider。
ContentProvider是獲取數據和存儲都用的是統一的封裝接口，涉及到Uri的概念。
當然了，如果用到Uri了，我們可以使用Google提供的工具類 UriMatcher 和 ContentUris ，以下會講到這些。
ContentProvider 優點
- 可以獲取系統原生一些App的數據。
- 不同App之間可以共享數據。
- 對數據進行封裝，存儲和獲取提供統一的API。
Android 自帶的ContentProvider
如果想獲取一些系統自帶App的數據，可以參考：
android.provider 包下的ContentProvider。
ContentProvider Uri 結構
content://com.camnter.content.provider/message/6
- content:// ：Scheme
- com.camnter.content.provider ：Authority（主機名），這個ContentProvider的唯一標識。
- message ：Table（表名）
- 6 ：Id
幾個例子：
content://com.camnter.content.provider/message：表示操作message表的所有記錄。
content://com.camnter.content.provider/message/6：表示操作message表的Id = 6的記錄。
content://com.camnter.content.provider/message/6/content：表示操作message表的Id = 6的記錄的content字段。
Google Uri 工具類
UriMatcher ：
public void addURI(String authority, String path, int code)：添加Uri，Uri會被添加到一個ArrayList裏，提供match(Uri uri)去匹配。public int match(Uri uri)：根據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的源碼特別簡單，整個類就調用了Uri類的兩個方法 T T# 。
所以就看看UriMatcher源碼吧。
由於對其他類的依賴不多，我就自定義了一份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.
* 創建Uri樹的根節點
*
* @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.
* 添加一個URI匹配，並且這裏添加code值會在這個URI匹配成功的時候返回。URI節點可能精確匹配字符串，
* token爲“*”的時候會匹配爲text，token爲“#”的時候只會匹配爲數字
* <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.
* 匹配路徑，*可能是作爲一個通配符用於任何文本,和#可能用作通配符數字。
*
* @param code the code that is returned when a URI is matched
* against the given components. Must be positive.
* 該URI匹配成功時返回的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.
* 嘗試匹配一個url的路徑。
*
* @param uri The url whose path we will match against.
* 將匹配的url路徑。
*
* @return The code for the matched node (added using addURI),
* or -1 if there is no matched node.
* 匹配節點設置的code（在使用addURI時，給對應URI設置code），
* 或者沒有匹配節點，則反悔-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;
}以上註釋還有使用，Google告訴我們怎麼使用UriMatcher的範例代碼。
自定義 ContentProvider
代碼都重複看過，都寫上了註釋。
BaseContentProvider
public abstract class BaseContentProvider extends ContentProvider {
// 單一數據的MIME類型字符串應該以vnd.android.cursor.item/開頭
protected static final String MIME_SINGLE = "vnd.android.cursor.item/";
// 數據集的MIME類型字符串則應該以vnd.android.cursor.dir/開頭
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 {
// 主機名
private static final String AUTHORITY = "com.camnter.content.provider";
// Message uri
public static final Uri MESSAGE_URI = Uri.parse("content://" + AUTHORITY + "/message");
// 數據集的MIME類型字符串則應該以vnd.android.cursor.dir/開頭
private static final String TOPIC_SINGLE = MIME_SINGLE + "message";
// 單一數據的MIME類型字符串應該以vnd.android.cursor.item/開頭
private static final String TOPIC_MULTIPLE = MIME_MULTIPLE + "message";
// 有id匹配碼
private static final int MESSAGE = 6;
// 有無匹配碼
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替換舊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;
// 把其它條件附加上
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;
// 把其它條件附加上
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;
// 把其它條件附加上
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() {
// 實例化LinearLayoutManager
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
// 設置垂直佈局
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
// 設置佈局管理器
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，該信息被用於自身的優化
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;
}
}
}