SettingsProvider 之 SqlArguments

最新推荐文章于 2024-07-02 16:58:27 发布

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#SettingsProvider #SqlArguments

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本文详细解析了如何通过ContentUri获取数据表名、投影和条件参数等信息，并介绍了SqlArguments类的具体实现细节。

转载请注明出处：http://blog.youkuaiyun.com/droyon/article/details/35558611

SqlArguments

    /**
     * Decode a content URL into the table, projection, and arguments
     * used to access the corresponding database rows.
     */

包装请求的ContentUri，插入的数据表、projection，where cause等。

1、限定请求的url地址

if (url.getPathSegments().size() == 1) {
// of the form content://settings/secure, arbitrary where clause
2、必须为content://settings/secure/brightness，包含两级pathSegmentselse if (url.getPathSegments().size() != 2) { throw new IllegalArgumentException("Invalid URI: " + url);

SqlArguments(Uri url, String where, String[] args) {
            if (url.getPathSegments().size() == 1) {
                // of the form content://settings/secure, arbitrary where clause
                this.table = url.getPathSegments().get(0);
                if (!DatabaseHelper.isValidTable(this.table)) {
                    throw new IllegalArgumentException("Bad root path: " + this.table);
                }
                this.where = where;
                this.args = args;
            } else if (url.getPathSegments().size() != 2) {
                throw new IllegalArgumentException("Invalid URI: " + url);
            } else if (!TextUtils.isEmpty(where)) {
                throw new UnsupportedOperationException("WHERE clause not supported: " + url);
            } else {
                // of the form content://settings/secure/element_name, no where clause
                this.table = url.getPathSegments().get(0);
                if (!DatabaseHelper.isValidTable(this.table)) {
                    throw new IllegalArgumentException("Bad root path: " + this.table);
                }
                if (TABLE_SYSTEM.equals(this.table) || TABLE_SECURE.equals(this.table) ||
                    TABLE_GLOBAL.equals(this.table)) {
                    this.where = Settings.NameValueTable.NAME + "=?";
                    final String name = url.getPathSegments().get(1);
                    this.args = new String[] { name };
                    // Rewrite the table for known-migrated names
                    if (TABLE_SYSTEM.equals(this.table) || TABLE_SECURE.equals(this.table)) {
                        if (sSecureGlobalKeys.contains(name) || sSystemGlobalKeys.contains(name)) {
                            this.table = TABLE_GLOBAL;
                        }
                    }
                } else {
                    // of the form content://bookmarks/19
                    this.where = "_id=" + ContentUris.parseId(url);
                    this.args = null;
                }
            }
        }

3、where必须为empty

else if (!TextUtils.isEmpty(where)) {
throw new UnsupportedOperationException("WHERE clause not supported: " + url);
}

4、

               this.table = url.getPathSegments().get(0);
                if (!DatabaseHelper.isValidTable(this.table)) {
                    throw new IllegalArgumentException("Bad root path: " + this.table);
                }
                if (TABLE_SYSTEM.equals(this.table) || TABLE_SECURE.equals(this.table) ||
                    TABLE_GLOBAL.equals(this.table)) {
                    this.where = Settings.NameValueTable.NAME + "=?";
                    final String name = url.getPathSegments().get(1);
                    this.args = new String[] { name };
                    // Rewrite the table for known-migrated names
                    if (TABLE_SYSTEM.equals(this.table) || TABLE_SECURE.equals(this.table)) {
                        if (sSecureGlobalKeys.contains(name) || sSystemGlobalKeys.contains(name)) {//更改table名
                            this.table = TABLE_GLOBAL;
                        }
                    }
                } else {
                    // of the form content://bookmarks/19
                    this.where = "_id=" + ContentUris.parseId(url);
                    this.args = null;
                }