首页 \ 问答 \ 当与ViewPager一起使用选项卡时，获取错误“Java.lang.IllegalStateException Activity已被销毁”(Getting the error “Java.lang.IllegalStateException Activity has been destroyed” when using tabs with ViewPager)

当与ViewPager一起使用选项卡时，获取错误“Java.lang.IllegalStateException Activity已被销毁”(Getting the error “Java.lang.IllegalStateException Activity has been destroyed” when using tabs with ViewPager)

 我有一个应用程序，包括在选项卡模式下使用ActionBarSherlock。我有5个选项卡，每个选项卡的内容都使用片段来处理。 对于tab2而言，我有一个片段，其xml文件包含一个ViewPager元素，后者又有一些片段页面。 当我最初启动应用程序的应用程序时，我可以在选项卡之间切换没有问题，但是当我第二次按tab2时，我得到上面提到的错误。 主要活动如下： 
 

public class MainActivity extends SherlockFragmentActivity
{
    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ActionBar actionBar = getSupportActionBar();

        ActionBar.Tab tab1 = actionBar.newTab().setText("Tab1");
        ActionBar.Tab tab3 = actionBar.newTab().setText("Tab3");
        ActionBar.Tab tab2 = actionBar.newTab().setText("Tab2");
        ActionBar.Tab tab4 = actionBar.newTab().setText("Tab4");
        ActionBar.Tab tab5 = actionBar.newTab().setText("Tab5");

        Fragment fragment1 = new Tab1();
        Fragment fragment3 = new Tab3();
        Fragment fragment2 = new Tab2();
        Fragment fragment5 = new Tab5();
        Fragment fragment4 = new Tab4();

        tab1.setTabListener(new MyTabListener(fragment1));
        tab3.setTabListener(new MyTabListener(fragment3));
        tab2.setTabListener(new MyTabListener(fragment2));
        tab5.setTabListener(new MyTabListener(fragment5));
        tab4.setTabListener(new MyTabListener(fragment4));

        actionBar.addTab(tab1);
        actionBar.addTab(tab2);
        actionBar.addTab(tab3);
        actionBar.addTab(tab4);
        actionBar.addTab(tab5); 

        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    }

    class MyTabListener implements ActionBar.TabListener
    {
        Fragment fragment;

        public MyTabListener(Fragment fragment)
        {
            this.fragment = fragment;
        }

        @Override
        public void onTabSelected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft) 
        {
            ft.replace(R.id.fragment_container,fragment);
        }

        @Override
        public void onTabUnselected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft) 
        {

        }

        @Override
        public void onTabReselected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft) 
        {

        }
    }
}

 

 没有ViewPager的片段类如下： 
 

public class Tab1 extends Fragment 
{
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState)
    {
        return inflater.inflate(R.layout.activity_tab1, container, false);
    }
}

 

 ViewPager的片段类如下： 
 

public class Tab2 extends Fragment 
{
    ViewPager mViewPager;
    private MyFragmentPagerAdapter mMyFragmentPagerAdapter;  
    private static int NUMBER_OF_PAGES = 5;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState)
    {
        View view =  inflater.inflate(R.layout.activity_tab2, container, false); 
        return view;
    }

    @Override
    public void onViewCreated(View view,Bundle savedInstanceState)
    {
        super.onViewCreated(view, savedInstanceState);
        mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
        mMyFragmentPagerAdapter = new MyFragmentPagerAdapter(getChildFragmentManager());  
        mViewPager.setAdapter(mMyFragmentPagerAdapter);  
    }

    private static class MyFragmentPagerAdapter extends FragmentPagerAdapter 
    {    
        public MyFragmentPagerAdapter(FragmentManager fm) 
        {  
             super(fm);  
        }  

        @Override  
        public Fragment getItem(int index) 
        {  
             return PageFragment.newInstance("My Message " + index);
        }  

        @Override  
        public int getCount() 
        {  
             return NUMBER_OF_PAGES;  
        }  
   }
}

 

 从我在不同地方阅读的内容（如果我错了，请更正我），这是因为第二遍的片段管理器尝试重用不存在的活动的片段，从而导致错误。但是我不知道为什么这样会发生在这里，因为我没有使用片段活动。 根据logcat的错误是在Tab2类，onViewCreated方法的行上说的mViewPager.setAdapter（mMyFragmentPagerAdapter）。 任何帮助非常感谢...谢谢。 
 

03-04 12:01:05.468: E/AndroidRuntime(2474): FATAL EXCEPTION: main
03-04 12:01:05.468: E/AndroidRuntime(2474): java.lang.IllegalStateException: Activity has been destroyed
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1342)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:578)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:139)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.view.ViewPager.populate(ViewPager.java:1011)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.view.ViewPager.populate(ViewPager.java:880)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.view.ViewPager.setAdapter(ViewPager.java:433)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at com.example.tabs.Tab2.onViewCreated(Tab2.java:31)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:925)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:429)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.os.Handler.handleCallback(Handler.java:587)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.os.Handler.dispatchMessage(Handler.java:92)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.os.Looper.loop(Looper.java:123)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.app.ActivityThread.main(ActivityThread.java:3687)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at java.lang.reflect.Method.invokeNative(Native Method)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at java.lang.reflect.Method.invoke(Method.java:507)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at dalvik.system.NativeStart.main(Native Method)


I have an application that consists of using ActionBarSherlock in tab mode.I have 5 tabs and the content of each tab is handled using fragments. For tab2 though, I have a fragment the xml file of which holds a ViewPager element which in turn has some fragment pages. When I initially start the application the application, I am able to switch between tabs no problem but when I press on tab2 for the second time I get the error mentioned above. The main activity is as follows:
 

public class MainActivity extends SherlockFragmentActivity
{
    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ActionBar actionBar = getSupportActionBar();

        ActionBar.Tab tab1 = actionBar.newTab().setText("Tab1");
        ActionBar.Tab tab3 = actionBar.newTab().setText("Tab3");
        ActionBar.Tab tab2 = actionBar.newTab().setText("Tab2");
        ActionBar.Tab tab4 = actionBar.newTab().setText("Tab4");
        ActionBar.Tab tab5 = actionBar.newTab().setText("Tab5");

        Fragment fragment1 = new Tab1();
        Fragment fragment3 = new Tab3();
        Fragment fragment2 = new Tab2();
        Fragment fragment5 = new Tab5();
        Fragment fragment4 = new Tab4();

        tab1.setTabListener(new MyTabListener(fragment1));
        tab3.setTabListener(new MyTabListener(fragment3));
        tab2.setTabListener(new MyTabListener(fragment2));
        tab5.setTabListener(new MyTabListener(fragment5));
        tab4.setTabListener(new MyTabListener(fragment4));

        actionBar.addTab(tab1);
        actionBar.addTab(tab2);
        actionBar.addTab(tab3);
        actionBar.addTab(tab4);
        actionBar.addTab(tab5); 

        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    }

    class MyTabListener implements ActionBar.TabListener
    {
        Fragment fragment;

        public MyTabListener(Fragment fragment)
        {
            this.fragment = fragment;
        }

        @Override
        public void onTabSelected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft) 
        {
            ft.replace(R.id.fragment_container,fragment);
        }

        @Override
        public void onTabUnselected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft) 
        {

        }

        @Override
        public void onTabReselected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft) 
        {

        }
    }
}

 

The fragment class without the ViewPager is as follows:
 

public class Tab1 extends Fragment 
{
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState)
    {
        return inflater.inflate(R.layout.activity_tab1, container, false);
    }
}

 

The fragment class with the ViewPager is as follows:
 

public class Tab2 extends Fragment 
{
    ViewPager mViewPager;
    private MyFragmentPagerAdapter mMyFragmentPagerAdapter;  
    private static int NUMBER_OF_PAGES = 5;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState)
    {
        View view =  inflater.inflate(R.layout.activity_tab2, container, false); 
        return view;
    }

    @Override
    public void onViewCreated(View view,Bundle savedInstanceState)
    {
        super.onViewCreated(view, savedInstanceState);
        mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
        mMyFragmentPagerAdapter = new MyFragmentPagerAdapter(getChildFragmentManager());  
        mViewPager.setAdapter(mMyFragmentPagerAdapter);  
    }

    private static class MyFragmentPagerAdapter extends FragmentPagerAdapter 
    {    
        public MyFragmentPagerAdapter(FragmentManager fm) 
        {  
             super(fm);  
        }  

        @Override  
        public Fragment getItem(int index) 
        {  
             return PageFragment.newInstance("My Message " + index);
        }  

        @Override  
        public int getCount() 
        {  
             return NUMBER_OF_PAGES;  
        }  
   }
}

 

From what I've read in different places (and please correct me if I'm wrong), this happens because the fragment manager on the second pass tries to reuse the fragments from the activity which doesn't exist anymore thus giving the error.But I'm not sure why this happens over here since I'm not using fragment activity. According to logcat the error is in the Tab2 class, onViewCreated method on the line that says mViewPager.setAdapter(mMyFragmentPagerAdapter). Any help is greatly appreciated...Thanks.
 

03-04 12:01:05.468: E/AndroidRuntime(2474): FATAL EXCEPTION: main
03-04 12:01:05.468: E/AndroidRuntime(2474): java.lang.IllegalStateException: Activity has been destroyed
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1342)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:578)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:139)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.view.ViewPager.populate(ViewPager.java:1011)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.view.ViewPager.populate(ViewPager.java:880)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.view.ViewPager.setAdapter(ViewPager.java:433)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at com.example.tabs.Tab2.onViewCreated(Tab2.java:31)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:925)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:429)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.os.Handler.handleCallback(Handler.java:587)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.os.Handler.dispatchMessage(Handler.java:92)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.os.Looper.loop(Looper.java:123)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at android.app.ActivityThread.main(ActivityThread.java:3687)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at java.lang.reflect.Method.invokeNative(Native Method)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at java.lang.reflect.Method.invoke(Method.java:507)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
03-04 12:01:05.468: E/AndroidRuntime(2474):     at dalvik.system.NativeStart.main(Native Method)


原文：https://stackoverflow.com/questions/15207305
更新时间：2023-06-08 17:06

最满意答案

 Xcode 8.2.1•Swift 3.0.2 
 

 

import UIKit

class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {

    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var filterButton: UIButton!
    @IBOutlet weak var saveButton: UIButton!

    let destinationUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        .appendingPathComponent("filteredImage.png")
    let imagePicker = UIImagePickerController()
    let messageFrame = UIView()
    var activityIndicator = UIActivityIndicatorView()
    var strLabel = UILabel()

    let effectView = UIVisualEffectView(effect: UIBlurEffect(style: .dark))

    func activityIndicator(_ title: String) {

        strLabel.removeFromSuperview()
        activityIndicator.removeFromSuperview()
        effectView.removeFromSuperview()

        strLabel = UILabel(frame: CGRect(x: 50, y: 0, width: 160, height: 46))
        strLabel.text = title
        strLabel.font = UIFont.systemFont(ofSize: 14, weight: UIFontWeightMedium)
        strLabel.textColor = UIColor(white: 0.9, alpha: 0.7)

        effectView.frame = CGRect(x: view.frame.midX - strLabel.frame.width/2, y: view.frame.midY - strLabel.frame.height/2 , width: 160, height: 46)
        effectView.layer.cornerRadius = 15
        effectView.layer.masksToBounds = true

        activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .white)
        activityIndicator.frame = CGRect(x: 0, y: 0, width: 46, height: 46)
        activityIndicator.startAnimating()

        effectView.addSubview(activityIndicator)
        effectView.addSubview(strLabel)
        view.addSubview(effectView)
    }

    func saveImage() {
        do {
            try imageView.image?.data?.write(to: destinationUrl, options: .atomic)
            print("file saved")
        } catch {
            print(error)
        }
    }

    func applyFilterToImage() {
        imageView.image = imageView.image?.applying(contrast: 1.5)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        guard let url = URL(string: "https://upload.wikimedia.org/wikipedia/commons/a/a8/VST_images_the_Lagoon_Nebula.jpg"), let data = try? Data(contentsOf: url), let image = UIImage(data: data) else { return }
        view.backgroundColor = UIColor(white: 0, alpha: 1)
        imageView.image = image
    }

    @IBAction func startSavingImage(_ sender: AnyObject) {
        saveButton.isEnabled = false
        filterButton.isEnabled = false
        activityIndicator("Saving Image")
        DispatchQueue.main.async {
            self.saveImage()
            DispatchQueue.main.async {
                self.effectView.removeFromSuperview()
                self.saveButton.isEnabled = true
                self.filterButton.isEnabled = true
            }
        }
    }

    @IBAction func filterAction(_ sender: AnyObject) {
        filterButton.isEnabled = false
        saveButton.isEnabled = false
        activityIndicator("Applying Filter")
        DispatchQueue.main.async {
            self.applyFilterToImage()
            DispatchQueue.main.async {
                self.effectView.removeFromSuperview()
                self.filterButton.isEnabled = true
                self.saveButton.isEnabled = true
            }
        }
    }

    @IBAction func cameraAction(_ sender: AnyObject) {
        if UIImagePickerController.isSourceTypeAvailable(.camera) {
            imagePicker.delegate = self
            imagePicker.sourceType = .camera
            present(imagePicker, animated: true)
        }
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingImage image: UIImage!, editingInfo: [AnyHashable: Any]!) {
        dismiss(animated: true, completion: nil)
        imageView.image = image
    }

}

extension Data {
    var image: UIImage? { return UIImage(data: self) }
}

extension UIImage {
    var data: Data? { return UIImagePNGRepresentation(self) }
    func applying(contrast value: NSNumber) -> UIImage? {
        guard let ciImage = CIImage(image: self)?.applyingFilter("CIColorControls", withInputParameters: [kCIInputContrastKey: value]) else { return nil }
        UIGraphicsBeginImageContextWithOptions(size, false, scale)
        defer { UIGraphicsEndImageContext() }
        UIImage(ciImage: ciImage).draw(in: CGRect(origin: .zero, size: size))
        return UIGraphicsGetImageFromCurrentImageContext()
    }
}

 

 

 示例项目 

Xcode 8.2.1 • Swift 3.0.2
 

 

import UIKit

class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {

    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var filterButton: UIButton!
    @IBOutlet weak var saveButton: UIButton!

    let destinationUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        .appendingPathComponent("filteredImage.png")
    let imagePicker = UIImagePickerController()
    let messageFrame = UIView()
    var activityIndicator = UIActivityIndicatorView()
    var strLabel = UILabel()

    let effectView = UIVisualEffectView(effect: UIBlurEffect(style: .dark))

    func activityIndicator(_ title: String) {

        strLabel.removeFromSuperview()
        activityIndicator.removeFromSuperview()
        effectView.removeFromSuperview()

        strLabel = UILabel(frame: CGRect(x: 50, y: 0, width: 160, height: 46))
        strLabel.text = title
        strLabel.font = .systemFont(ofSize: 14, weight: UIFontWeightMedium)
        strLabel.textColor = UIColor(white: 0.9, alpha: 0.7)

        effectView.frame = CGRect(x: view.frame.midX - strLabel.frame.width/2, y: view.frame.midY - strLabel.frame.height/2 , width: 160, height: 46)
        effectView.layer.cornerRadius = 15
        effectView.layer.masksToBounds = true

        activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .white)
        activityIndicator.frame = CGRect(x: 0, y: 0, width: 46, height: 46)
        activityIndicator.startAnimating()

        effectView.addSubview(activityIndicator)
        effectView.addSubview(strLabel)
        view.addSubview(effectView)
    }

    func saveImage() {
        do {
            try imageView.image?.data?.write(to: destinationUrl, options: .atomic)
            print("file saved")
        } catch {
            print(error)
        }
    }

    func applyFilterToImage() {
        imageView.image = imageView.image?.applying(contrast: 1.5)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        guard let url = URL(string: "https://upload.wikimedia.org/wikipedia/commons/a/a8/VST_images_the_Lagoon_Nebula.jpg"), let data = try? Data(contentsOf: url), let image = UIImage(data: data) else { return }
        view.backgroundColor = UIColor(white: 0, alpha: 1)
        imageView.image = image
    }

    @IBAction func startSavingImage(_ sender: AnyObject) {
        saveButton.isEnabled = false
        filterButton.isEnabled = false
        activityIndicator("Saving Image")
        DispatchQueue.main.async {
            self.saveImage()
            DispatchQueue.main.async {
                self.effectView.removeFromSuperview()
                self.saveButton.isEnabled = true
                self.filterButton.isEnabled = true
            }
        }
    }

    @IBAction func filterAction(_ sender: AnyObject) {
        filterButton.isEnabled = false
        saveButton.isEnabled = false
        activityIndicator("Applying Filter")
        DispatchQueue.main.async {
            self.applyFilterToImage()
            DispatchQueue.main.async {
                self.effectView.removeFromSuperview()
                self.filterButton.isEnabled = true
                self.saveButton.isEnabled = true
            }
        }
    }

    @IBAction func cameraAction(_ sender: AnyObject) {
        if UIImagePickerController.isSourceTypeAvailable(.camera) {
            imagePicker.delegate = self
            imagePicker.sourceType = .camera
            present(imagePicker, animated: true)
        }
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingImage image: UIImage!, editingInfo: [AnyHashable: Any]!) {
        dismiss(animated: true, completion: nil)
        imageView.image = image
    }

}

extension Data {
    var image: UIImage? { return UIImage(data: self) }
}

extension UIImage {
    var data: Data? { return UIImagePNGRepresentation(self) }
    func applying(contrast value: NSNumber) -> UIImage? {
        guard let ciImage = CIImage(image: self)?.applyingFilter("CIColorControls", withInputParameters: [kCIInputContrastKey: value]) else { return nil }
        UIGraphicsBeginImageContextWithOptions(size, false, scale)
        defer { UIGraphicsEndImageContext() }
        UIImage(ciImage: ciImage).draw(in: CGRect(origin: .zero, size: size))
        return UIGraphicsGetImageFromCurrentImageContext()
    }
}

 

 

sample project
 

Xcode 9.0 • Swift 4.0
 

    func activityIndicator(_ title: String) {

        strLabel.removeFromSuperview()
        activityIndicator.removeFromSuperview()
        effectView.removeFromSuperview()

        strLabel = UILabel(frame: CGRect(x: 50, y: 0, width: 160, height: 46))
        strLabel.text = title
        strLabel.font = .systemFont(ofSize: 14, weight: .medium)
        strLabel.textColor = UIColor(white: 0.9, alpha: 0.7)

        effectView.frame = CGRect(x: view.frame.midX - strLabel.frame.width/2, y: view.frame.midY - strLabel.frame.height/2 , width: 160, height: 46)
        effectView.layer.cornerRadius = 15
        effectView.layer.masksToBounds = true

        activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .white)
        activityIndicator.frame = CGRect(x: 0, y: 0, width: 46, height: 46)
        activityIndicator.startAnimating()

        effectView.contentView.addSubview(activityIndicator)
        effectView.contentView.addSubview(strLabel)
        view.addSubview(effectView)
    }

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