如何让我的请求在后台运行，同时填充其他EditText（线程）？

Question

我是线程新手，但我有一个EditText视图，每当它失去焦点时，它就会使用用户从EditText输入的图像徽标填充回收视图。但是，每当用户失去焦点并调用该方法时，一切都会停止一段时间（这意味着我不擅长线程）。如何改进此代码，使其能够顺利运行？

我的活动类：

public class addItem extends AppCompatActivity {

    LoadingDialog loadingDialog;
    RecyclerView imgList;
    ArrayList<Bitmap> bitmapList = new ArrayList<>();
    BitmapAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
       /*
       / Code Unnecessary to the problem…
       */
       et_title.setOnFocusChangeListener((v, hasFocus) -> {
            if(!hasFocus){
                getImageLogo(et_title.getText().toString());
            }
        });
    }

    @SuppressLint("NotifyDataSetChanged")
    private void getImageLogo(String serviceName){
        googleRequest googleList = new googleRequest(serviceName);
        googleList.start();
        try {
            googleList.join();
        } catch (InterruptedException e) {
            Log.e("Interrupted Error","Thread Was Interrupted unexpectedly",e);
        }
        if(googleList.getImgRealList() != null) {
            bitmapList.clear();
            bitmapList.addAll(googleList.getImgRealList());
        }else {
            bitmapList.clear();
        }
        adapter.notifyDataSetChanged();
    }

我的googleRequest类：

public class googleRequest extends Thread {

    private ArrayList<Bitmap> imgRealList;
    private final String keyword;

    public googleRequest(String keyword){
        this.keyword = keyword;
    }

    public ArrayList<Bitmap> getImgRealList() {
        return imgRealList;
    }

    @Override
    public void run() {
        String newKeyword = keyword.toLowerCase(Locale.ROOT);
        newKeyword = newKeyword.replace(' ','+');
        String url = "https://www.google.gr/search?bih=427&biw=1835&hl=el&gbv=1&tbm=isch&og=&ags=&q="+ newKeyword;
        try {
            Document document = Jsoup.connect(url).get();
            imgRealList = new ArrayList<>();
            Elements imgList = document.select("img");
            for (int i=1;i<imgList.size();i++) {
                if(i==8)
                    break;
                String imgSrc = imgList.get(i).absUrl("src");
                InputStream input = new java.net.URL(imgSrc).openStream();
                Bitmap bitmap = BitmapFactory.decodeStream(input);
                imgRealList.add(bitmap);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

这是一个如何使用回调实现它的示例，正如我在评论中提到的。为此，我们需要定义一个回调函数，我将其命名为下面的函数，为了方便起见，您可以更改名称。

它是一个简单的java接口。

/// Must be executed in the UI (main) thread.
@MainThread
public interface RequestConsumer {
    void onRequestResult(List<Bitmap> bitmaps);
}

googleRequest线程类。

public class googleRequest extends Thread {

    private ArrayList<Bitmap> imgRealList;
    private final String keyword;
    /*
    We will use the request consumer callback in order to deliver the results
    to the UI from background. Since we need to touch the UI by this callback
    we ensure that it will execute within the UI thread's queue using the
    uiHandler.
    */
    private final RequestConsumer requestConsumer;
    private final Handler uiHandler = new Handler(Looper.getMainLooper());

    public googleRequest(@NonNull String keyword, @NonNull RequestConsumer requestConsumer){
        this.keyword = keyword;
        this.requestConsumer = requestConsumer;
    }

    @Override
    public void run() {
        String newKeyword = keyword.toLowerCase(Locale.ROOT);
        newKeyword = newKeyword.replace(' ','+');
        String url = "https://www.google.gr/search?bih=427&biw=1835&hl=el&gbv=1&tbm=isch&og=&ags=&q="+ newKeyword;
        try {
            Document document = Jsoup.connect(url).get();
            imgRealList = new ArrayList<>();
            Elements imgList = document.select("img");
            for (int i=1;i<imgList.size();i++) {
                if(i==8)
                    break;
                String imgSrc = imgList.get(i).absUrl("src");
                InputStream input = new java.net.URL(imgSrc).openStream();
                Bitmap bitmap = BitmapFactory.decodeStream(input);
                imgRealList.add(bitmap);
            }

            // I think according to your code; the data you've requested is ready
            // to deliver from now on. But attention! we post it to execute it in the UI thread
            uiHandler.post(() -> requestConsumer.onRequestResult(imgRealList));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

addItem活动类

public class addItem extends AppCompatActivity {

    LoadingDialog loadingDialog;
    RecyclerView imgList;
    ArrayList<Bitmap> bitmapList = new ArrayList<>();
    BitmapAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
       /*
       / Code Unnecessary to the problem…
       */
       et_title.setOnFocusChangeListener((v, hasFocus) -> {
            if(!hasFocus){
                getImageLogo(et_title.getText().toString());
            }
        });
    }

    @SuppressLint("NotifyDataSetChanged")
    private void getImageLogo(String serviceName){
        googleRequest googleList = new googleRequest(serviceName, images -> {
            // Here we get the delivered results in this callback
            if(images != null) {
                bitmapList.clear();
                bitmapList.addAll(images);
            }else {
                bitmapList.clear();
            }
            adapter.notifyDataSetChanged();
        });
        googleList.start();


    }
}

注意，我已经在文本编辑器中编写了它，因此代码需要一些功能测试。