Android GreenDao 條件查詢問題

問題描述

使用GreenDao保存了全國城市的屬性(名字，代碼,省份等等),保存可以成功，無條件查詢全部數據時可以成功:

private List<CityInfo> queryCitiesInfo(){List<CityInfo> cityInfos = mCityQUery.list();for (int i = 0; i < cityInfos.size(); i++) { Log.d(TAG,'所有的城市CountryEn'+cityInfos.get(i).getCountryEn());}return cityInfos; }

但是使用條件查詢，時數據為0，不知道哪里出錯了，對了下屬性，沒知道原因：

//這個方法查詢的數據為0private void queryCitiesByLeader(){mCityInfoDao = nDaoSession.getCityInfoDao();mCityQUery = mCityInfoDao.queryBuilder().orderAsc(CityInfoDao.Properties.Id).build();List<CityInfo> cityInfos = mCityInfoDao.queryBuilder().where(CityInfoDao.Properties.CountryEn.eq('China')).orderAsc(CityInfoDao.Properties.Id).list();for (int i = 0; i < cityInfos.size(); i++) { Log.d(TAG,'條件查詢城市名稱' + cityInfos.get(i).getCityEn());} }

@Entitypublic class CityInfo {@Id private Long id; private String cityEn; private String cityZh; private String countryCode; private String countryEn; private String countryZh; private String provinceEn; private String provinceZh; private String leaderEn; private String leaderZh; private String lat; private String lon; @Generated(hash = 69148619) public CityInfo(Long id, String cityEn, String cityZh, String countryCode, String countryEn, String countryZh, String provinceEn, String provinceZh, String leaderEn, String leaderZh, String lat, String lon) {this.id = id;this.cityEn = cityEn;this.cityZh = cityZh;this.countryCode = countryCode;this.countryEn = countryEn;this.countryZh = countryZh;this.provinceEn = provinceEn;this.provinceZh = provinceZh;this.leaderEn = leaderEn;this.leaderZh = leaderZh;this.lat = lat;this.lon = lon; } @Generated(hash = 300452937) public CityInfo() { } public Long getId() {return this.id; } public void setId(Long id) {this.id = id; } public String getCityEn() {return this.cityEn; } public void setCityEn(String cityEn) {this.cityEn = cityEn; } public String getCityZh() {return this.cityZh; } public void setCityZh(String cityZh) {this.cityZh = cityZh; } public String getCountryCode() {return this.countryCode; } public void setCountryCode(String countryCode) {this.countryCode = countryCode; } public String getCountryEn() {return this.countryEn; } public void setCountryEn(String countryEn) {this.countryEn = countryEn; } public String getCountryZh() {return this.countryZh; } public void setCountryZh(String countryZh) {this.countryZh = countryZh; } public String getProvinceEn() {return this.provinceEn; } public void setProvinceEn(String provinceEn) {this.provinceEn = provinceEn; } public String getProvinceZh() {return this.provinceZh; } public void setProvinceZh(String provinceZh) {this.provinceZh = provinceZh; } public String getLeaderEn() {return this.leaderEn; } public void setLeaderEn(String leaderEn) {this.leaderEn = leaderEn; } public String getLeaderZh() {return this.leaderZh; } public void setLeaderZh(String leaderZh) {this.leaderZh = leaderZh; } public String getLat() {return this.lat; } public void setLat(String lat) {this.lat = lat; } public String getLon() {return this.lon; } public void setLon(String lon) {this.lon = lon; }}

下面是部分日志,打印出CountryEn:

第一次用GreenDao， 找了很久沒發現問題，望解答，感謝。

問題解答

沒有看到你的表結構及數據字段結構組成，沒法準確判斷你的問題了，我對你的“China”條件存疑，你檢查你的條件是否正確。