Joblogs——ContentValues的使用

ContentValues在Android的SQLiteDatabase.update (String table, ContentValues values, String whereClause, String[] whereArgs)中以参数的形式使用。

至于ContentValues的具体使用。查看SQLiteDatabase.update 方法源码：

public int updateWithOnConflict(String table, ContentValues values,
String whereClause, String[] whereArgs, int conflictAlgorithm) {
if (values == null || values.size() == 0) {
throw new IllegalArgumentException("Empty values");
}

acquireReference();
try {
StringBuilder sql = new StringBuilder(120);
sql.append("UPDATE ");
sql.append(CONFLICT_VALUES[conflictAlgorithm]);
sql.append(table);
sql.append(" SET ");

// move all bind args to one array
int setValuesSize = values.size();
int bindArgsSize = (whereArgs == null) ? setValuesSize : (setValuesSize + whereArgs.length);
Object[] bindArgs = new Object[bindArgsSize];
int i = 0;
for (String colName : values.keySet()) {
sql.append((i > 0) ? "," : "");
sql.append(colName);
bindArgs[i++] = values.get(colName);
sql.append("=?");
}
if (whereArgs != null) {
for (i = setValuesSize; i < bindArgsSize; i++) {
bindArgs[i] = whereArgs[i - setValuesSize];
}
}
if (!TextUtils.isEmpty(whereClause)) {
sql.append(" WHERE ");
sql.append(whereClause);
}

SQLiteStatement statement = new SQLiteStatement(this, sql.toString(), bindArgs);
try {
return statement.executeUpdateDelete();
} finally {
statement.close();
}
} finally {
releaseReference();
}
}

ContentValues，使用Has和Map来保存数据，同时还可以序列化：

public final class ContentValues implements Parcelable {
public static final String TAG = "ContentValues";

/** Holds the actual values */
private HashMap<String, Object> mValues;

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