安卓Cursor封装，取值带设置默认值

目的

有时候，使用Cursor查询数据库中某个不存在的字段时，要求能返回一个默认值。

代码

class CursorHelper(private var cursor: Cursor?) {

    init {
        if (cursor == null) {
            Log.e("", "cursor is null")
        }
    }

    fun swapCursor(cursor: Cursor) {
        this.cursor = cursor
    }

    fun getBoolean(columnName: String?, defValue: Boolean): Boolean {
        return try {
            if (cursor == null) {
                defValue
            } else {
                cursor!!.getInt(cursor!!.getColumnIndexOrThrow(columnName)) != 0
            }
        } catch (e: Exception) {
            e.printStackTrace()
            defValue
        }
    }

    fun getFloat(columnName: String?, defValue: Float): Float {
        return try {
            cursor?.getFloat(cursor!!.getColumnIndexOrThrow(columnName)) ?: defValue
        } catch (e: Exception) {
            e.printStackTrace()
            defValue
        }
    }

    fun getInt(columnName: String?, defValue: Int): Int {
        return try {
            cursor?.getInt(cursor!!.getColumnIndexOrThrow(columnName)) ?: defValue
        } catch (e: Exception) {
            e.printStackTrace()
            defValue
        }
    }

    fun getDouble(columnName: String?, defValue: Double): Double {
        return try {
            cursor?.getDouble(cursor!!.getColumnIndexOrThrow(columnName)) ?: defValue
        } catch (e: Exception) {
            e.printStackTrace()
            defValue
        }
    }

    fun getLong(columnName: String?, defValue: Long): Long {
        return try {
            cursor?.getLong(cursor!!.getColumnIndexOrThrow(columnName)) ?: defValue
        } catch (e: Exception) {
            e.printStackTrace()
            defValue
        }
    }

    fun getString(columnName: String?, defValue: String): String {
        return try {
            cursor?.getString(cursor!!.getColumnIndexOrThrow(columnName)) ?: defValue
        } catch (e: Exception) {
            e.printStackTrace()
            defValue
        }
    }

    fun moveToNext(): Boolean {
        return cursor != null && cursor!!.moveToNext()
    }

    fun moveToFirst(): Boolean {
        return cursor != null && cursor!!.moveToFirst()
    }

    fun getCount(): Int {
        return if (cursor == null) {
            0
        } else {
            cursor!!.count
        }
    }

    fun close() {
        if (cursor != null && !cursor!!.isClosed) {
            cursor!!.close()
        }
    }

    companion object {
        fun from(cursor: Cursor?): CursorHelper {
            return CursorHelper(cursor)
        }
    }

}
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示例

int limitSecond = cursorHelper.getInt(TIME_LIMIT, Integer.MAX_VALUE)
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作者：帅得不敢出门