javascript ng-cordova sqlite 插件：TypeError：无法读取 null 的属性“transaction”
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ng-cordova sqlite plugin: TypeError: Cannot read property 'transaction' of null
提问by Chucky
I am trying to get values from database using ionic, ng-cordova, sqlitebut i keep getting this error:
我正在尝试使用 ionic、ng-cordova、sqlite从数据库中获取值，但我不断收到此错误：
TypeError: Cannot read property 'transaction' of null: ionic.bundle.js:19387
Here is the code:
这是代码：
HTML
HTML
<ion-view view-title="Search" ng-controller="AppCtrl2">
<ion-content>
<ion-list>
<ion-item ng-repeat="item in resultados">
Hello, {{item}}!
</ion-item>
</ion-list>
</ion-content>
</ion-view>
app.js
应用程序.js
var db = null;
angular.module('starter', ['ionic', 'starter.controllers','ngCordova'])
.run(function($ionicPlatform,$cordovaSQLite) {
$ionicPlatform.ready(function() {
// Hide the accessory bar by default (remove this to show the accessory bar above the keyboard
// for form inputs)
if (window.cordova && window.cordova.plugins.Keyboard) {
cordova.plugins.Keyboard.hideKeyboardAccessoryBar(true);
}
if (window.StatusBar) {
// org.apache.cordova.statusbar required
StatusBar.styleDefault();
}
db = $cordovaSQLite.openDB({ name: "my.db" });
$cordovaSQLite.execute(db, "CREATE TABLE IF NOT EXISTS people (id integer primary key, firstname text, lastname text)");
query = "INSERT INTO people (firstname, lastname) VALUES (?,?)";
$cordovaSQLite.execute(db, query, ["Sumit", "Pal"]).then(function(res) {
console.log("INSERT ID -> " + res.insertId);
});
$cordovaSQLite.execute(db, query, ["Sumti2", "Pal"]);
});
})
controller
控制器
.controller('AppCtrl2', function($scope,$ionicPlatform,$cordovaSQLite) {
$ionicPlatform.ready(function() {
function getCat() {
var selectQuery = "SELECT * FROM people";
$cordovaSQLite.execute(db, selectQuery).then(function(result) {
nombres = [];
for(var i=0; i<result.rows.length; i++){
nombres.push({"nombre":result.rows.item(0).firstname});
}
})
}
$scope.resultados = getCat();
})
});
How can i fix it ? The error could be of because device is not yet ready ?
我该如何解决？错误可能是因为设备尚未准备好？
回答by Charles Mendes
Case you do test your app on Browser/Chrome for example, at windows Console (F12) to be error transaction of null, thats ok!!
如果您在浏览器/Chrome 上测试您的应用程序，例如，在 Windows 控制台 (F12) 是 null 的错误事务，那没问题！！
For good test, you would deploy app ionic any device android or ios, or emulated avd.
为了进行良好的测试，您可以在任何设备 android 或 ios 或模拟 avd 上部署应用程序 ionic。
Look my test github example ng-cordova sqlite SELECT and INSERT commands, good luck!
看看我的测试 github 示例 ng-cordova sqlite SELECT 和 INSERT 命令，祝你好运！
https://github.com/CharlesMendes/ionic-sqlite
and
https://github.com/CharlesMendes/comandos-basicos
https://github.com/CharlesMendes/ionic-sqlite
和
https://github.com/CharlesMendes/comandos-basicos
APP.js
应用程序js
$scope.select = function(lastname) {
var query = "SELECT firstname, lastname FROM people WHERE lastname = ?";
$cordovaSQLite.execute(db, query, [lastname]).then(function(res) {
if(res.rows.length > 0) {
var message = "SELECTED -> " + res.rows.item(0).firstname + " " + res.rows.item(0).lastname;
alert(message);
console.log(message);
} else {
alert("No results found");
console.log("No results found");
}
}, function (err) {
alert(err);
console.error(err);
});
}
Deploy do app Android
部署 do app Android
ionic build android
Install apk your device/smartphone android for test
安装 apk 您的设备/智能手机 android 进行测试
adb install -r platforms/android/ant-build/CordovaApp-debug.apk
回答by bocong
You can manually bootstrap the app after the platform is ready Initialize my angularJs App after Phonegap deviceready
您可以在平台准备好后手动引导应用 程序在 Phonegap deviceready 之后初始化我的 angularJs 应用程序
Or you can first navigate to a static loading page, once all the initialization logic is complete in the platform ready method, then navigates to the first functional page
或者您可以先导航到一个静态加载页面，一旦在平台就绪方法中完成所有初始化逻辑，然后导航到第一个功能页面
回答by Kooldandy
Do some changes.
做一些改变。
Remove database connection from app.run(). Put that code in factory service
dbConnection :function(){ if (window.cordova) { dbconn = $cordovaSQLite.openDB({ name: "my.db" , location: 'default'}); $cordovaSQLite.execute(dbconn, "CREATE TABLE IF NOT EXISTS people (id integer primary key, firstname text, lastname text)"); } else{ dbconn = window.openDatabase("my.db", '1', 'my', 1024 * 1024 * 100); $cordovaSQLite.execute(dbconn, "CREATE TABLE IF NOT EXISTS people (id integer primary key, firstname text, lastname text)"); } return dbconn; }Call your
getCat()function on device ready.document.addEventListener("deviceready", onDeviceReady, false); function onDeviceReady() { $scope.resultados = getCat(); }
从 app.run() 中删除数据库连接。将该代码放入工厂服务中
dbConnection :function(){ if (window.cordova) { dbconn = $cordovaSQLite.openDB({ name: "my.db" , location: 'default'}); $cordovaSQLite.execute(dbconn, "CREATE TABLE IF NOT EXISTS people (id integer primary key, firstname text, lastname text)"); } else{ dbconn = window.openDatabase("my.db", '1', 'my', 1024 * 1024 * 100); $cordovaSQLite.execute(dbconn, "CREATE TABLE IF NOT EXISTS people (id integer primary key, firstname text, lastname text)"); } return dbconn; }getCat()在准备好设备上调用您的函数。document.addEventListener("deviceready", onDeviceReady, false); function onDeviceReady() { $scope.resultados = getCat(); }
回答by Richard Long
$cordovaSQLite.openDB now requires a compulsory location parameter. Change
$cordovaSQLite.openDB 现在需要一个强制性的位置参数。改变
db = $cordovaSQLite.openDB({ name: "my.db" });
to
到
db = $cordovaSQLite.openDB({ name: "my.db", location:"default" });
回答by user7069287
I found the solution for this,
我找到了解决方案，
just declare your variable name above the function in index.jsand hence it will load the DB name throughout the controller.
只需在index.js 中的函数上方声明您的变量名称，因此它将在整个控制器中加载数据库名称。
var myDB;
(function() {
"use strict";
document.addEventListener('deviceready', onDeviceReady.bind(this), false);
function onDeviceReady() {
// Handle the Cordova pause and resume events
document.addEventListener('pause', onPause.bind(this), false);
document.addEventListener('resume', onResume.bind(this), false);
// TODO: Cordova has been loaded. Perform any initialization that requires Cordova here.
var element = document.getElementById("deviceready");
myDB = window.sqlitePlugin.openDatabase({
name: "mySQLite.db",
location: 'default'
});
element.innerHTML = 'Device Ready';
element.className += ' ready';
};
});In Tutorials they have defined myDB within function
在教程中，他们在函数中定义了 myDB
