NSPathStore2的UIImageView实例泄漏
我正在将Document目录中的png图像加载到UIImageView中。使用xcode 调试内存图时，它会遇到内存问题：
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
public class LibrarySystem {
/** The menu option that will cause the program to end. */
private static final int QUIT_OPTION = 4;
/** The Library to use in the test program. */
private static Library myLibrary = null;
/**
The start point for the program.
@param args no command line arguments are used in this program
*/
public static void main(String[] args) {
/*
Create a Scanner for the input file.
This program assumes that Books.txt exists in the
same directory as this program.
*/
Scanner input = null;
try {
input = new Scanner(new File("Books.txt"));
} catch (FileNotFoundException e) {
System.out.println("File \"Books.txt\" not found in the current directory.");
System.out.println("Exiting the program.");
System.exit(1);
}
/* Read the input file and create the library */
myLibrary = readFile(input);
// create a Scanner for keyboard input
Scanner console = new Scanner(System.in);
boolean runAgain = true;
//display an introduction
displayIntro();
while (runAgain) { // loop until the user chooses to quit
displayMenu();
// get the user's menu choice
int choice = promptForMenuChoice(console, "\nEnter your choice (1 - "
+ QUIT_OPTION + "): ");
// perform some processing based on the menu choice
if (choice == QUIT_OPTION) {
runAgain = false;
} else {
doMenuChoice(choice);
}
}
displayExitMessage();
} // end main
/**
Reads the input file and returns a Library built from the
data in the input file.
@param input A Scanner over the input file
@return a Library built from the data in the input file
*/
private static Library readFile(final Scanner input) {
Library theLibrary = new Library();
/* read the file and populate the Library */
while (input.hasNextLine()) {
//read the first line which is a book title
String title = input.nextLine();
//create an ArrayList for the authors
ArrayList<String> theAuthors = new ArrayList<String>();
//read the authors
boolean readingAuthors = true;
while (input.hasNext() && readingAuthors) {
String author = input.nextLine();
if (author.length() == 0) { //blank line between books
readingAuthors = false;
} else {
theAuthors.add(author);
}
}
Book nextBook = null;
try {
nextBook = new Book(title, theAuthors);
} catch (IllegalArgumentException e) {
continue; //skip to next book in input file
}
theLibrary.add(nextBook);
}
return theLibrary;
} //end readFile
/** Displays an introduction to the program. */
private static void displayIntro() {
System.out.println("\nThis program manages a library of books.");
}
/** Displays the menu of options for the program. */
private static void displayMenu() {
System.out.println("\nProgram Options:");
System.out.println("\n1) Display books");
System.out.println("\n2) Add a book");
System.out.println("\n3) Search by title");
System.out.println("\n4) Quit");
System.out.println("\nPlease type a number and then press the Enter key.");
}
/**
* Prompts for a menu choice in the range 1 to QUIT_OPTION.
*
* @param console a Scanner to read from the keyboard
* @param prompt the prompt to display
* @return the number entered by the user
*/
private static int promptForMenuChoice(final Scanner console, final String prompt) {
int choice = getInt(console, prompt);
while (choice < 1 || choice > QUIT_OPTION) {
System.out.println("Invalid selection. Please try again.");
choice = getInt(console, prompt);
}
return choice;
}
/**
* Prompts for an integer until an integer is entered.
*
* This method is adopted from getInt() of
* "Building Java Programs" by Reges and Stepp
*
* @param console a Scanner used to capture user input
* @param prompt a prompt to the user
* @return the integer entered by the user
*/
private static int getInt(final Scanner console, final String prompt) {
System.out.print(prompt);
while (!console.hasNextInt()) {
console.next();
System.out.println("Invalid selection. Please try again.");
System.out.print(prompt);
}
return console.nextInt();
}
/**
Initiates processing based on the user's menu choice.
@param choice the user's menu choice
*/
private static void doMenuChoice(final int choice) {
//Code for each switch option will usually be a call to some method.
//By just calling a method from each case we can keep this code block clean
switch (choice) {
case 1:
displayBooks();
break;
case 2:
addABook();
break;
case 3:
searchByTitle();
break;
default :
break;
}
}
private static void displayBooks() {
//System.out.println("\n" + myLibrary);
myLibrary.sort();
System.out.println("\nBy title:\n" + myLibrary);
}
private static void addABook() {
String title = getTitle();
ArrayList<String> authors = getAuthors();
Book newBook = new Book(title, authors);
myLibrary.add(newBook);
}
private static void searchByTitle() {
String title = getTitle();
List<Book> found = myLibrary.titleSearch(title);
if (found.size() == 0) {
System.out.println("\nSorry, \"" + title + "\" was not found.");
} else {
System.out.println("\n\"" + title + "\" was found!");
Iterator<Book> scan = found.iterator();
while (scan.hasNext()) {
System.out.println(scan.next());
}
}
}
private static String getTitle() {
Scanner console = new Scanner(System.in);
System.out.print("\nEnter the book title: ");
return console.nextLine();
}
private static ArrayList<String> getAuthors() {
Scanner console = new Scanner(System.in);
ArrayList<String> theAuthors = new ArrayList<String>();
//prompt for the authors
boolean readingAuthors = true;
while (readingAuthors) {
System.out.println("\nEnter an author's name");
System.out.print("or just press Enter after adding the last author: ");
String author = console.nextLine();
if (author.length() == 0) { //blank line
readingAuthors = false;
} else {
theAuthors.add(author);
}
}
return theAuthors;
}
/* Displays an exit message. */
private static void displayExitMessage() {
System.out.println("\nThanks for trying this program. Have a nice day.");
}
} // end class LibrarySystem
我听说仪器的泄漏工具可能报告错误的leaks。
内存似乎没有增加：
问题似乎出在UIImage中，请参阅Instruments Leak报告：
以下是生成图像的代码：
instances of NSPathStore2 leaked产生此问题的工作项目可以在这里找到：UIImageViewNSPathStore2leaked
是否有办法更改代码以消除这些泄漏，或者这是那些虚假的报告之一？
2 个答案:
答案 0 :(得分：6)
我也有问题。
复制
只需创建干净的新项目来重现该问题。
- 将image.png拖到项目中，确保在复制捆绑资源中进行。
- 在viewDidLoad中写这两行。
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let path = Bundle.main.path(forResource: "image", ofType: "png")!
let _ = UIImage(contentsOfFile: path)
}
}
- 构建并运行它。
- 在出现viewController时，单击调试内存图。
- 您可以看到泄漏问题。
不确定是init(contentsOfFile:)的错误吗？
解决方案
我更改了API init(data:)而不是init(contentsOfFile:)来解决问题。
let url = Bundle.main.url(forResource: "image", withExtension: "png")!
let imageData = try! Data(contentsOf: url)
let _ = UIImage(data: imageData)
使用Xcode 11.5 / 11.3.1和Swift 5
答案 1 :(得分：0)
似乎是Instruments中的错误，可能是误报。在Xcode 12 beta 6中，它不再显示为泄漏。
请注意，在Xcode 11.6 / 11.7中，“泄漏”也通过UIImage(named: )方法发生：
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