Display images from Salesforce Document folder

Question

I currently managed to display some images(from salesforce Documents folder) on an extracted Excel sheet from Salesforce but I have hard coded the document Ids. So this might not work after creating package and after installing to different orgs.

I'm looking for a way to get the document Ids without hard coding them. Is there any way doing this ?

Apex Code:-

            movementDirUp = System.URL.getSalesforceBaseUrl().toExternalForm().replace('https','http')+'/servlet/servlet.ImageServerid=015240000005U3V&oid='+UserInfo.getOrganizationId();
            movementDirDown = System.URL.getSalesforceBaseUrl().toExternalForm().replace('https','http')+'/servlet/servlet.ImageServer?id=015240000005U3T&oid='+UserInfo.getOrganizationId();
            movementDirRight = System.URL.getSalesforceBaseUrl().toExternalForm().replace('https','http')+'/servlet/servlet.ImageServer?id=015240000005U3U&oid='+UserInfo.getOrganizationId();
            //Map to display images
            mapClimateMovement = new Map<String, String>{'climate_up_arrow' => movementDirUp , 'climate_down_arrow' => movementDirDown , 'climate_right_arrow' => movementDirRight.toLowerCase()};

Visualforce Code:-

<apex:image value="{!IF(CONTAINS(reportRow.parentInfo[field],'Up'),mapClimateMovement['risk_climate_up_arrow'],'')}"  rendered="{!CONTAINS(reportRow.parentInfo[field],'Up')}" />
                                <apex:image value="{!IF(CONTAINS(reportRow.parentInfo[field],'Down'),mapClimateMovement['risk_climate_down_arrow'],'')}" rendered="{!CONTAINS(reportRow.parentInfo[field],'Down')}" />
                                <apex:image value="{!IF(CONTAINS(reportRow.parentInfo[field],'Level'),mapClimateMovement['risk_climate_right_arrow'],'')}" rendered="{!CONTAINS(reportRow.parentInfo[field],'Level')}"/>

Answer 1

You can use something like this

List<String> lstDocNames; //Populate list with document names
Map<String, id> mapDocs; 

public void getDocuments(){
    mapDocs = new Map<id, String>();
    for(Document d: [Select Id from Document d where d.DeveloperName in :lstDocNames]){
        mapDocs.put(d.name, d.id); 
    }
}

Answer 2

You can perform a query on the document object. Something like this:

public Document doc;

public void setDocument(){
    this.doc = [Select Id from Document d where d.DeveloperName = 'DocumentUniqueName']
}

public string DocId {
    get {
        return doc.id
    }
}

This requires that you know the unique name assigned to the document. This will be the same in every instance you install your package

Now you can make a property that returns the Id of this document object so that you can reference it in your servlet urls.

Sorry for terrible formatting on my cell phone..

Answer 3

to retrieve the Id from the Map instead of hard coded Id, used the following line. movementDirUp = System.URL.getSalesforceBaseUrl().toExternalForm().replace('https','http')+'/servlet/servlet.ImageServer?id='+residualDocs.get('Climate_Up_Arrow')+'&oid='+UserInfo.getOrganizationId();