[TIMOB-13642] Android: Fixed bug where "relative" image paths won't load

[jquick-axway]

JIRA:
https://jira.appcelerator.org/browse/TIMOB-13642

Summary:

• Relative image path was broken due to extra slash added to path, which Android asset manager could not handle.
  • Solved by trimming extra slashes.
  • Not an issue with external files since filesystem can handle extra slashes.
• Fixed resolution of paths containing "../" when loading an image from a JS file in a subdirectory.
• Added support for "content://" image URLs. (Used to only work via blobs.)
• Added support for "android.resource://" image URLs. (Used to only work via blobs.)
  • Allows Ti.Filesystem.getResRawDirectory() + "MyImage" to work.
  • Allows "android.resource://" + Ti.App.id + "/drawable/MyImage" to work.

Note:
Relative paths are currently handled differently between platforms.

• On Android, paths are relative to the JavaScript file.
• On iOS and Windows, paths are relative to the app's "Resources" directory.

I have not changed this behavior since that would be a breaking-change.

Test:

1. Create a "Classic App" project.
2. Replace the project's "app.js" with the code below. (This code assumes the project has a "tab1.png".)
3. Build and run the app on Android.
4. Scroll through the app, verifying that every black box has loaded an image.

function createImageGroupFor(path) {
	var container = Ti.UI.createView({
		layout: "vertical",
		top: "5dp",
		left: "5dp",
		right: "5dp",
		backgroundColor: "#222222",
		width: Ti.UI.FILL,
		height: Ti.UI.SIZE,
	});
	container.add(Ti.UI.createLabel({
		text: path,
		color: "#CCCCCC",
		top: "5dp",
		left: "5dp",
		right: "5dp",
	}));
	container.add(Ti.UI.createImageView({
		image: path,
		preventDefaultImage: true,
		bottom: "5dp",
		width: "80dp",
		height: "80dp",
	}));
	return container;
}

var window = Ti.UI.createWindow({ fullscreen: true });
var scrollView = Ti.UI.createScrollView({
	layout: "vertical",
	scrollType: "vertical",
	showHorizontalScrollIndicator: false,
	shorVerticalScrollIndicator: true,
	backgroundColor: "gray",
});
scrollView.add(createImageGroupFor("/assets/images/tab1.png"));
scrollView.add(createImageGroupFor("assets/images/tab1.png"));
scrollView.add(createImageGroupFor("./assets/images/tab1.png"));
scrollView.add(createImageGroupFor("././assets/images/.././images/tab1.png"));
scrollView.add(createImageGroupFor(Ti.Filesystem.getFile("assets/images/tab1.png").nativePath));
if (Ti.Platform.name === "android") {
	var externalFilePath = Ti.Filesystem.applicationDataDirectory + "copy.png";
	Ti.Filesystem.getFile(Ti.Filesystem.resourcesDirectory, "assets/images/tab1.png").copy(externalFilePath);
	scrollView.add(createImageGroupFor(externalFilePath));
	externalFilePath = Ti.Filesystem.getFile(externalFilePath).nativePath;
	scrollView.add(createImageGroupFor(externalFilePath));
	externalFilePath = externalFilePath.substring("file:///".length);
	scrollView.add(createImageGroupFor("content://" + Ti.App.id + ".tifileprovider/filesystem/" + externalFilePath));
	scrollView.add(createImageGroupFor(Ti.Filesystem.resourcesDirectory + "assets/images/tab1.png"));
	scrollView.add(createImageGroupFor("file:///android_asset/Resources/assets/images/tab1.png"));
	scrollView.add(createImageGroupFor("android.resource://" + Ti.App.id + "/drawable/appicon"));
}
scrollView.add(Ti.UI.createView({ width: Ti.UI.FILL, height: "5dp" }));
window.add(scrollView);
window.open();

[garymathews]

I was able to simplify this a little:

private static String trimFront(String sourceString, char trimCharacter)
{
	if (sourceString != null) {
		for (int i = 0; i < sourceString.length(); i++) {
			if (sourceString.charAt(i) != trimCharacter) {
				sourceString = sourceString.substring(i);
				break;
			}
		}
	}
	return sourceString;
}

[jquick-axway]

This doesn't handle the case where all characters in the string are trimmable. That's why I do the substring handling outside of the loop.

[garymathews]

I think that a for is a little easier to read than a while in this case:

private static String trimFront(String sourceString, char trimCharacter)
{
  if (sourceString != null) {
    int i = 0;
    for (; i < sourceString.length(); i++) {
      if (sourceString.charAt(i) != trimCharacter) {
        sourceString = sourceString.substring(i);
        break;
      }
    }
    if (i == sourceString.length()) {
      sourceString = "";
    }
  }
  return sourceString;
}

But they both work, so I'll let you decide.

[jquick-axway]

I originally wrote it with a for like this...

for (; (index < sourceString.length()) && (sourceString.charAt(index) == trimCharacter); index++);

But our lint step didn't like it. (shrugs)

[garymathews]

Could we use TiFileFactory.FILE_URL_SCHEME here? Or even FILE_URL_PREFIX

[jquick-axway]

Yeah, we have several "file:" string literals in the "TiURL.java" code.
I also don't like how "TiURL.java" expects a scheme string to end with a trailing colon ':' either. That's not part of the scheme. That's the character which separates the scheme from the path.

I didn't feel like mucking with this part and left it alone.

[lokeshchdhry]

FR Passed.

Relative path images load successfully.

Studio Ver: 5.1.1.201809051655
SDK Ver: 7.5.0 local build
OS Ver: 10.13.5
Xcode Ver: Xcode 9.4.1
Appc NPM: 4.2.13
Appc CLI: 7.0.6
Daemon Ver: 1.1.3
Ti CLI Ver: 5.1.1
Alloy Ver: 1.13.2
Node Ver: 8.9.1
NPM Ver: 5.5.1
Java Ver: 10.0.2
Devices: ⇨ google Nexus 5 (Android 6.0.1)
⇨ samsung SM-G955U1 (Android 8.0.0)

[lokeshchdhry]

Waiting for CR to pass.

[build]

	Messages
📖	💾 Here's the generated SDK zipfile.

Generated by 🚫 dangerJS

[garymathews]

CR: PASS