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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