如何将图像从 URL 加载到 Java Android？ 代码没有错误，但它不起作用

Question

I'm working on a new Android Java program which brings two variables (String title and String imageUrl) then adds buttons named as the String (title).

When the user click on a button the application must load the image from the url in String (imageUrl).

The problem which I face is that none of the load images methodes worked with me!!

Although my project has no errors at all!!

This is my code:

public void start(String res) {
    try {
        JSONArray jarray = new JSONArray(jsonString);
        for (int k = 0; k < jarray.length(); k++) {
            JSONObject obj = jarray.getJSONObject(k);
            Button btn = new Button(this);
            btn.setText(obj.getString("title"));
            final String link = obj.getString("link"); 
            btn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    openImage(link);
                }
            });
            space.addView(btn);
            dialog.dismiss();
        }
    } catch(Exception e) {
    }
}
public void openImage(final String urk) {
    dialog = ProgressDialog.show(this, "", "loading...", true);
    new Thread(new Runnable() {
        public void run() {
            nextstepload(urk);
        }
    });
}
public void nextstepload(final String urk) {
    try {
        ImageView im = findViewById(R.id.img);
        URL url = new URL(urk);
        Bitmap image = BitmapFactory.decodeStream(url.openConnection().getInputStream()); 
        im.setImageBitmap(image); 
        dialog.dismiss(); 
    } catch(IOException e) {
        System.out.println(e);
    }
}

And my Xml form is:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:id="@+id/displayer">
        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/img"/>
    </LinearLayout>
</LinearLayout>

Notice: I read the previous writings about this subject on StackOverFlow but none of them helps me enough. I may need a code suitable for my project especially.

Thanks very much

Answer 1

Give it a try to Glide. https://github.com/bumptech/glide

You can load images like this:

Glide
    .with(context)
    .load(YOUR URL HERE - AS STRING)
    .placeholder(R.drawable.loading_spinner) // if you want some placeholder, it comes here
    .into(myImageView); // The imageview reference.

Answer 2

You just forgot to Thread.start()

new Thread(new Runnable() {
    public void run() {
        nextstepload(urk);
    }
}).start();

A Thread object itself does nothing. You must .start() it after instantiated.