將ContentProvider封裝成SharedPreference相同使用方式

摘要： 一、初略介紹 ContentProvider，即內容提供者，是 Android 四大元件之一。主要功能是程序間資料互動/共享。詳細內容請看這篇文章：Android：關於ContentProvider的知識都在這裡了！ 二、程式碼實現 1、首先...

一、初略介紹

ContentProvider，即內容提供者，是 Android 四大元件之一。主要功能是程序間資料互動/共享。詳細內容請看這篇文章：Android：關於ContentProvider的知識都在這裡了！

二、程式碼實現

1、首先要在一個應用中註冊ContentProvider元件

/**
 * 定義一個儲存contentprovider資料的資料庫
 */
public class WhhConfigDB extends SQLiteOpenHelper {

private static final String DATABASE_NAME = "whhconfig.db";
private static final int DATABASE_VERSION = 1;

public WhhConfigDB(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {

String sql = "CREATE TABLE IF NOT EXISTS " + WhhConfigConstant.TABLE_NAME + "(" +
WhhConfigConstant._ID + " integer primary key autoincrement," +
WhhConfigConstant.KEY + " text," +
WhhConfigConstant.VALUE + " text" +
")";
db.execSQL(sql);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.d("whh", "WhhConfigDB onUpgrade");
}

}

/**
 * 定義一個ContentProvider,記得在AndroidManifest.xml中靜態註冊
 */
public class WhhConfigProvider extends ContentProvider {
private WhhConfigDB sharedDB;
private static final UriMatcher MATCHER;
private static final int SHARES = 1;
//private static final int SHARE = 2;
static {
MATCHER = new UriMatcher(UriMatcher.NO_MATCH);
MATCHER.addURI(WhhConfigConstant.AUTHORITY, WhhConfigConstant.TABLE_NAME, SHARES);
//MATCHER.addURI("com.evideo.kmbox.kmshareprovider", "kmshare/#", SHARE);
}

@Override
public boolean onCreate() {
EvLog.d("WhhConfigProvider onCreate...");
//在這建立資料庫
this.sharedDB = new WhhConfigDB(this.getContext());
return false;
}

@Override
public Cursor query(@NonNull Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteDatabase db = sharedDB.getReadableDatabase();
if (db == null) {
return null;
}
switch (MATCHER.match(uri)) {
case SHARES:
return db.query(WhhConfigConstant.TABLE_NAME, projection, selection, selectionArgs,
null, null, sortOrder);

//case SHARE:
//long id = ContentUris.parseId(uri);
//String where = "_id=" + id;
//if (selection != null && !"".equals(selection)) {
//where = selection + " and " + where;
//}
//return db.query("kmshare", projection, where, selectionArgs, null,
//null, sortOrder);
default:
throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());
}
}

//返回資料的MIME型別。
@Override
public String getType(@NonNull Uri uri) {
switch (MATCHER.match(uri)) {
case SHARES:
return WhhConfigConstant.DIR_TYPE;
//case SHARE:
//return "vnd.android.cursor.item/kmshare";
default:
throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());
}
}

@Override
public Uri insert(@NonNull Uri uri, ContentValues values) {
SQLiteDatabase db = sharedDB.getWritableDatabase();
if (db == null) {
return null;
}
switch (MATCHER.match(uri)) {
case SHARES:
// 第二個引數是當key欄位為空時，將自動插入一個NULL。
long rowid = db.insert(WhhConfigConstant.TABLE_NAME, WhhConfigConstant.KEY, values);
Uri insertUri = ContentUris.withAppendedId(uri, rowid);
//this.getContext().getContentResolver().notifyChange(uri, null);
ContentResolver cr = this.getContext().getContentResolver();
if (cr != null) {
cr.notifyChange(Uri.withAppendedPath(uri, values.getAsString(WhhConfigConstant.KEY)), null);
}

return insertUri;
default:
throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());
}
}

@Override
public int delete(@NonNull Uri uri, String selection, String[] selectionArgs) {
SQLiteDatabase db = sharedDB.getWritableDatabase();
if (db == null) {
return 0;
}
int count = 0;
switch (MATCHER.match(uri)) {
case SHARES:
count = db.delete(WhhConfigConstant.TABLE_NAME, selection, selectionArgs);
return count;

//case SHARE:
//long id = ContentUris.parseId(uri);
//String where = "_id=" + id;
//if (selection != null && !"".equals(selection)) {
//where = selection + " and " + where;
//}
//count = db.delete("kmshare", where, selectionArgs);
//return count;

default:
throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());
}
}

@Override
public int update(@NonNull Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
SQLiteDatabase db = sharedDB.getWritableDatabase();
if (db == null) {
return 0;
}
int count = 0;
switch (MATCHER.match(uri)) {
case SHARES:
count = db.update(WhhConfigConstant.TABLE_NAME, values, selection, selectionArgs);
ContentResolver cr = this.getContext().getContentResolver();
if (cr != null) {
cr.notifyChange(Uri.withAppendedPath(uri, values.getAsString(WhhConfigConstant.KEY)), null);
}
return count;
//case SHARE:
//long id = ContentUris.parseId(uri);
//String where = "_id=" + id;
//if (selection != null && !"".equals(selection)) {
//where = selection + " and " + where;
//}
//count = db.update("kmshare", values, where, selectionArgs);
//return count;
default:
throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());
}
}
}

//注意在AndroidManifest.xml中靜態註冊一下ContentProvider
<provider
android:name=".provider.WhhConfigProvider"
android:authorities="com.whh.shareprovider"
android:exported="true" />

/**
 * 資料庫常量類
 */
public class KmConfigConstant {
public static final String AUTHORITY = "com.evideo.kmbox.kmshareprovider";
public static final String TABLE_NAME = "tblWhhconfig";
public static final String DIR_TYPE = "vnd.android.cursor.dir/tblKmconfig";
public static final String KEY = "key";
public static final String VALUE = "value";
public static final String _ID = "_id";
public static final String SCHEME = "content://";
public static final String URI = "content://com.whh.shareprovider/tblWhhconfig";
public static final String SELECTION = "key=?";
}

三、封裝呼叫

public class WhhConfigManager {
private Uri selectUri;
private Context mContext;

private WhhConfigManager() {
this.selectUri = Uri.parse("content://com.whh.shareprovider/tblWhhconfig");
this.mContext = ApplicationUtil.getInstance();
}

public static WhhConfigManager getInstance() {
return WhhConfigManager.LazyHold.sInstance;
}

public boolean putBoolean(String key, boolean value) {
String bValue = String.valueOf(value);
return this.put(key, bValue);
}

public boolean putString(String key, String value) {
return this.put(key, value);
}

public boolean putInt(String key, int value) {
String iValue = String.valueOf(value);
return this.put(key, iValue);
}

public boolean putLong(String key, long value) {
String lValue = String.valueOf(value);
return this.put(key, lValue);
}

public boolean putFloat(String key, float value) {
String fValue = String.valueOf(value);
return this.put(key, fValue);
}

private boolean put(String key, String value) {
if (TextUtils.isEmpty(key)) {
return false;
} else {
ContentResolver cr = this.mContext.getContentResolver();
ContentValues cv = new ContentValues();
cv.put("key", key);
cv.put("value", value);
if (!this.contains(key)) {
cr.insert(this.selectUri, cv);
} else {
cr.update(this.selectUri, cv, "key=?", new String[]{key});
}

cr.notifyChange(this.selectUri, (ContentObserver)null);
return true;
}
}

public boolean getBoolean(String key, boolean def) {
if (TextUtils.isEmpty(key)) {
return def;
} else {
ContentResolver cr = this.mContext.getContentResolver();
Cursor c = cr.query(this.selectUri, (String[])null, "key=?", new String[]{key}, (String)null);
if (c == null) {
return def;
} else if (!c.moveToFirst()) {
c.close();
return def;
} else {
int col = c.getColumnIndex("value");
String value = c.getString(col);
c.close();
return Boolean.valueOf(value);
}
}
}

public String getString(String key, String def) {
ContentResolver cr = this.mContext.getContentResolver();
Cursor c = cr.query(this.selectUri, (String[])null, "key=?", new String[]{key}, (String)null);
if (c == null) {
return def;
} else if (!c.moveToFirst()) {
c.close();
return def;
} else {
int col = c.getColumnIndex("value");
String value = c.getString(col);
c.close();
return value;
}
}

public int getInt(String key, int def) {
ContentResolver cr = this.mContext.getContentResolver();
Cursor c = cr.query(this.selectUri, (String[])null, "key=?", new String[]{key}, (String)null);
if (c == null) {
return def;
} else if (!c.moveToFirst()) {
c.close();
return def;
} else {
int col = c.getColumnIndex("value");
String value = c.getString(col);
c.close();
return Integer.valueOf(value);
}
}

public float getFloat(String key, float def) {
ContentResolver cr = this.mContext.getContentResolver();
Cursor c = cr.query(this.selectUri, (String[])null, "key=?", new String[]{key}, (String)null);
if (c == null) {
return def;
} else if (!c.moveToFirst()) {
c.close();
return def;
} else {
int col = c.getColumnIndex("value");
String value = c.getString(col);
c.close();
return Float.valueOf(value);
}
}

public Long getLong(String key, long def) {
ContentResolver cr = this.mContext.getContentResolver();
Cursor c = cr.query(this.selectUri, (String[])null, "key=?", new String[]{key}, (String)null);
if (c == null) {
return def;
} else if (!c.moveToFirst()) {
c.close();
return def;
} else {
int col = c.getColumnIndex("value");
String value = c.getString(col);
c.close();
return Long.valueOf(value);
}
}

public boolean contains(String key) {
ContentResolver cr = this.mContext.getContentResolver();
Cursor c = cr.query(this.selectUri, (String[])null, "key=?", new String[]{key}, (String)null);
if (c == null) {
return false;
} else if (!c.moveToFirst()) {
c.close();
return false;
} else {
c.close();
return true;
}
}

public boolean remove(String key) {
ContentResolver cr = this.mContext.getContentResolver();
int result = cr.delete(this.selectUri, "key=?", new String[]{key});
return result != -1;
}

public Map<String, String> getAllInfo() {
Map<String, String> contentInfo = new HashMap();
ContentResolver cr = this.mContext.getContentResolver();
Cursor c = cr.query(this.selectUri, (String[])null, (String)null, (String[])null, (String)null);
if (c == null) {
return contentInfo;
} else {
while(c.moveToNext()) {
int colKey = c.getColumnIndex("key");
int colValue = c.getColumnIndex("value");
contentInfo.put(c.getString(colKey), c.getString(colValue));
}

c.close();
return contentInfo;
}
}

public void registerContentObserver(ContentObserver observer) {
if (observer != null) {
this.mContext.getContentResolver().registerContentObserver(this.selectUri, true, observer);
}
}

public void unregisterContentObserver(ContentObserver observer) {
if (observer != null) {
this.mContext.getContentResolver().unregisterContentObserver(observer);
}
}

private static class LazyHold {
static final WhhConfigManager sInstance = new WhhConfigManager();

private LazyHold() {
}
}
}