我正在编写一个 phonegap/jquery 移动应用程序并且有一个我似乎无法解决的问题。
当应用程序加载（设备就绪和 jqm_mobile_init）触发并且应用程序创建/打开数据库并检查用户是否登录时（只是数据库中的一个标志）。如果是这样，应用程序调用 $.mobile.changePage("#home", {transition:"none"}); 将它们重定向到“主页”页面。
然后在“主页”页面显示事件中，我从数据库中获取大量信息并将其附加到主页内的列表视图中。
但是，第一次运行（使用 $.mobile.changePage 事件）时，不会触发 pageshow 事件（因此我的数据都不会附加到列表视图）。如果我浏览应用程序然后访问该页面，则数据显示正常。这只发生在使用 $.mobile.changePage 更改到主页时。
如何让 pageshow() 在 $.mobile.changePage 上触发？还是有其他方法可以做到这一点？
这是我的代码：
/************************************************
Try to create/open the DB, if not catch the error
***********************************************/
try {
if (!window.openDatabase) {
alert('not supported');
} else {
var shortName = 'test';
var version = '1.0';
var displayName = 'test Database';
var maxSize = 200000; // in bytes
// database instance in db.
var db = openDatabase(shortName, version, displayName, maxSize);
// Create tables
createTables(db);
// Check if there is a signedin user
isUserSignedInQuery(db);
}
} catch(e) {
// Error handling code goes here.
if (e == 2) {
// Version number mismatch.
alert("Invalid database version.");
} else {
alert("Unknown error "+e+".");
}
return;
}
// Universal null/blank data handler
function nullDataHandler(transaction, results) { }
// Universal error callback
function errorHandler(error) {
//alert("Error processing SQL: " +error.message+ " Error Code: " +error.code);
}
// Create tables if dont already exist
function createTables(db) {
db.transaction(
function (transaction) {
// create tables
}
);
}
/**********************************************************************************************
Check if there is a signed in user, if so redirect to listings page, if not display login page
**********************************************************************************************/
function isUserSignedInQuery(db) {
db.transaction(
function (transaction) {
transaction.executeSql("SELECT * FROM USERS WHERE signedIn=1;",
[], // array of values for the ? placeholders
isUserSignedInDataHandler, errorHandler);
}
);
}
function isUserSignedInDataHandler(transaction, results) {
// Handle the results
if (results.rows.length > 0) {
//console.log("someones logged in!");
// Assign signed in user to global var
console.log("logged in user = " + results.rows.item(0).id);
window.currentSignedInUserId = results.rows.item(0).id;
$.mobile.changePage( "#home", { transition: "none"} );
} else {
$.mobile.changePage( "#login", { transition: "none"} );
}
}
/**********************************************************************************************
Sign in page:
**********************************************************************************************/
function doesSigningInUserAlreadyExistQuery(db) {
db.transaction(
function (transaction) {
transaction.executeSql("SELECT * FROM USERS WHERE username='"+usernameValue+"' ORDER BY id LIMIT 0,1;",
[], // array of values for the ? placeholders
doesSigningInUserAlreadyExistDataHandler, errorHandler);
}
);
}
function doesSigningInUserAlreadyExistDataHandler(transaction, results) {
// User exists, sign them in.
if (results.rows.length > 0) {
//console.log("user exists");
// Find number of rows
var len = results.rows.length;
//console.log(len);
for (var i=0; i<len; i++){
//console.log(results.rows.item(i));
db.transaction(
function (transaction) {
transaction.executeSql('UPDATE USERS SET signedIn = 1 WHERE username="'+usernameValue+'"');
}
);
// Assign signed in user to global var
window.currentSignedInUserId = results.rows.item(0).id;
// Redirect to home/listings page
$.mobile.changePage( "#home", { transition: "slidefade"} );
}
// User is new, create them and sign them in
} else {
db.transaction(
function (transaction) {
transaction.executeSql('INSERT INTO USERS (username, password, userId, defaultHandler, autoSync, updateCaseTypes'
+', updateHistorical, updateFavorite, signedIn) '
+'VALUES ("'+usernameValue+'", "eclipse", "userid321", "Another User", 1, 1, 1, 1, 1);', [],
function (transaction, resultSet) {
if (!resultSet.rowsAffected) {
// Previous insert failed.
alert('No rows affected!');
return false;
}
alert('insert ID was '+resultSet.insertId);
//Assign signed in user to global var
window.currentSignedInUserId = resultSet.insertId;
});
}
);
// Redirect to home/listings page
$.mobile.changePage( "#home", {
reloadPage: true,
transition: "slidefade"} );
}
}
$('#login').live('pageshow', function(event) {
console.log(window.currentSignedInUserId); // This is empty - global var not working
// Should this be tap??????? Find out. -----------
$('a#signIn').click(function() {
// Get values of all fields & buld vars
var username = $('#login-username');
var password = $('#login-password');
// Check if fields are empty
if( !username.val() ) {
username.addClass('empty');
$('label.login-username').addClass('blank');
}
if( !password.val() ) {
password.addClass('empty');
$('label.login-password').addClass('blank');
}
// If both not empty, check if user exists, if so sql update if not sql insert
if (username.val() && password.val()) {
// Get username
usernameValue = username.val();
// Run function
doesSigningInUserAlreadyExistQuery(db);
}
});
});
$('#home').live('pageshow', function(event) {
console.log("Page show fired on recordings page");
db.transaction(getRecordingsQuery, getRecordingsDataHandler, errorHandler);
// get stuff, loop through it and append
// Refresh the list to add JQM styles etc
$('#recordings-list').listview('refresh');
}
});