问题描述
我查询CallLog内容提供商和需要检测列类型
I'm querying the CallLog content provider and need to detect the column types.
在蜂窝和更高版本（API等级11+），您可以通过调用方法得到一个列preferred数据类型 Cursor.getType（INT参数：columnIndex）返回以下类型之一：
In Honeycomb and newer (API Level 11+) you can get a columns preferred data type by calling the method Cursor.getType(int columnIndex) which returns one of the following types:
- FIELD_TYPE_NULL（0）
- FIELD_TYPE_INTEGER（1）
- FIELD_TYPE_FLOAT（2）
- FIELD_TYPE_STRING（3）
- FIELD_TYPE_BLOB（4）
我怎样才能做到这一点的pre-蜂窝＆LT; 11台设备
How can I accomplish this on pre-Honeycomb <11 devices?
我已经试过如下：
for ( int i = 0; i < cursor.getColumnCount(); i++ ) {
int columnType = -1;
try {
cursor.getInt( i );
columnType = Cursor.FIELD_TYPE_INTEGER;
} catch ( Exception ignore ) {
try {
cursor.getString( i );
columnType = Cursor.FIELD_TYPE_STRING;
} catch ( Exception ignore1 ) {
try {
cursor.getFloat( i );
columnType = Cursor.FIELD_TYPE_FLOAT;
} catch ( Exception ignore2 ) {
try {
cursor.getBlob( i );
columnType = Cursor.FIELD_TYPE_BLOB;
} catch ( Exception ignore3 ) {
columnType = Cursor.FIELD_TYPE_NULL;
}
}
}
}
}
但是，没有异常。该数据总是浇铸在要检查的第一类型，在这种情况下，调用getInt（）。这意味着，我得到了正确的值，如果列类型是整数但是 0 对于所有其他类型。
However, no exception is thrown. The data is always casted in the first type you are checking for, in this case getInt(). That means, I get the correct values if the column type is Integer but a 0 for all other types.
为什么我不看检查什么类型存储的文档中？列不同而有所不同设备制造商，而不是所有的人都记录在案，看到了这个问题：How处理制造商依赖于ContentProviders差异？
Why am I not looking in the documentation to check what type is stored?The columns differ depending on the device manufacturer and not all of them are documented, see this question: How to handle manufacturer-dependent differences in ContentProviders?
任何想法？
推荐答案
您可以使用此code时，光标定位在一个有效行：
You can use this code when cursor is positioned in a valid row:
CursorWrapper cw = (CursorWrapper)cursor;
Class<?> cursorWrapper = CursorWrapper.class;
Field mCursor = cursorWrapper.getDeclaredField("mCursor");
mCursor.setAccessible(true);
AbstractWindowedCursor abstractWindowedCursor = (AbstractWindowedCursor)mCursor.get(cw);
CursorWindow cursorWindow = abstractWindowedCursor.getWindow();
int pos = abstractWindowedCursor.getPosition();
for ( int i = 0; i < cursor.getColumnCount(); i++ ) {
String type = null;
if (cursorWindow.isNull(pos, i)) {
type = "Cursor.FIELD_TYPE_NULL";
} else if (cursorWindow.isLong(pos, i)) {
type = "Cursor.FIELD_TYPE_INTEGER";
} else if (cursorWindow.isFloat(pos, i)) {
type = "Cursor.FIELD_TYPE_FLOAT";
} else if (cursorWindow.isString(pos, i)) {
type = "Cursor.FIELD_TYPE_STRING";
} else if (cursorWindow.isBlob(pos, i)) {
type = "Cursor.FIELD_TYPE_BLOB";
}
}
需要注意的是Cursor.FIELD_TYPE_ *常量的定义从蜂巢开始。
Note that Cursor.FIELD_TYPE_* constant values are defined starting from HONEYCOMB.
这篇关于Cursor.getType（）的API级别＆LT; 11的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！