Question

我正在使用loopj的AsyncHttpClient来从互联网上获取图像文件并将其显示在典型的图像视图中。

我找到了一个名为FileAsyncHttpClient的方便处理程序，我检查了以下简单代码，以及我预期的。

public class MainActivity extends ActionBarActivity {
    ImageView imgView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        imgView = (ImageView) findViewById(R.id.imgView);

        AsyncHttpClient client = new AsyncHttpClient();
        client.get("http://www.some_image_url.png",
            new FileAsyncHttpResponseHandler(this){
                @Override
                public void onFailure(int statusCode, Header[] headers, Throwable throwable, File response) {}

                @Override
                public void onSuccess(int statusCode, Header[] headers, File response) {
                    imgView.setImageBitmap(BitmapFactory.decodeFile(response.getPath()));
                }
        });
    }
}

但是当我在ArrayAdpater课程中使用此代码时，Activity不在setImageBitmap(...)课程中，setVisibility(...)不起作用。此外，似乎不允许任何视图控制，例如public class MainActivity extends Activity { private List<CustomClass> objectList = new ArrayList<CustomClass>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // ... make objectList from given data ... (omitted) ArrayAdapter<CustomClass> adapter = new CustomListAdapter(); ListView list = (ListView) findViewById(R.id.customListView); list.setAdapter(adapter); } private class CustomListAdapter extends ArrayAdapter<CustomClass> { private View itemView; ImageView imgView; public MemberListAdapter() { super(MainActivity.this, R.layout.custom_list, objectList); } @Override public View getView(int position, View convertView, ViewGroup parent) { itemView = convertView; if(itemView == null){ itemView = getLayoutInflater().inflate(R.layout.custom_list, parent, false); } CustomClass currentObj = objectList.get(position); imgView = (ImageView) itemView.findViewById(R.id.imgView); AsyncHttpClient client = new AsyncHttpClient(); client.get("http://www.some_image_url.png", new FileAsyncHttpResponseHandler(this){ @Override public void onFailure(int statusCode, Header[] headers, Throwable throwable, File response) {} @Override public void onSuccess(int statusCode, Header[] headers, File response) { imgView.setImageBitmap(BitmapFactory.decodeFile(response.getPath())); } }); return itemView; } } }。

以下代码是有问题的。

.menu li.active a{
  color: blue;
}

.menu li a{
  color: red;
}

我不知道为什么这不起作用。请让我咨询一下。感谢。

P.S。我已经检查了控制器内部的控制视图，但是在处理程序之外是可能的。

Answer 1

我已经尝试过你的代码了，我没有看到任何错误，但这是我的。（我添加了一些增强功能，例如ViewHolder模式）。

主要活动。对不起一个大胖子。

public class LoopJAsync extends AppCompatActivity {

  @Override protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_loop_jasync);
    ListView myListView = (ListView) findViewById(R.id.my_list_view);

    List<MyObject> myObjectList = new ArrayList<>();
    for (String imageUrl : ImageData.URLS) {
      myObjectList.add(new MyObject(imageUrl));
    }
    ArrayAdapter<MyObject> adapter = new CustomListAdapter(myObjectList);
    myListView.setAdapter(adapter);
  }

  private class MyObject {
    public String url;

    public MyObject(String url) {
      this.url = url;
    }
  }

  private class CustomListAdapter extends ArrayAdapter<MyObject> {
    private View itemView;
    private List<MyObject> myObjectList = Collections.emptyList();

    public CustomListAdapter(List<MyObject> myObjectList) {
      super(LoopJAsync.this, R.layout.row_loopj_test, myObjectList);
      this.myObjectList = myObjectList;
    }

    @Override public View getView(int position, View convertView, ViewGroup parent) {
      itemView = convertView;
      if (convertView == null) {
        LayoutInflater inflater = getLayoutInflater();
        itemView = inflater.inflate(R.layout.row_loopj_test, null);
        // configure view holder
        ViewHolder viewHolder = new ViewHolder();
        viewHolder.imageView = (ImageView) itemView.findViewById(R.id.image);
        viewHolder.mProgressView = (ProgressBar) itemView.findViewById(R.id.progress);
        itemView.setTag(viewHolder);
      }

      // fill data
      final ViewHolder holder = (ViewHolder) itemView.getTag();
      MyObject currentObj = myObjectList.get(position);
      AsyncHttpClient client = new AsyncHttpClient();

      // Show the progress circle and show the image
      holder.mProgressView.setVisibility(View.VISIBLE);
      holder.imageView.setVisibility(View.GONE);
      client.get(currentObj.url, new FileAsyncHttpResponseHandler(LoopJAsync.this) {
        @Override public void onFailure(int statusCode, Header[] headers, Throwable throwable,
            File response) {
        }

        @Override public void onSuccess(int statusCode, Header[] headers, File response) {

          // Hide the progress circle and show the image
          holder.mProgressView.setVisibility(View.GONE);
          holder.imageView.setVisibility(View.VISIBLE);

          Log.i("success", " yup done. Look at status - " + statusCode);
          holder.imageView.setImageBitmap(BitmapFactory.decodeFile(response.getPath()));
        }
      });

      return itemView;
    }

    private class ViewHolder {
      ProgressBar mProgressView;
      ImageView imageView;
    }
  }
}

以下是ImageData类。

// From Picasso
// https://github.com/square/picasso/blob/master/picasso-sample%2Fsrc%2Fmain%2Fjava%2Fcom%2Fexample%2Fpicasso%2FData.java

final class ImageData {
  static final String BASE = "http://i.imgur.com/";
  static final String EXT = ".jpg";
  static final String[] URLS = {
      BASE + "CqmBjo5" + EXT, BASE + "zkaAooq" + EXT, BASE + "0gqnEaY" + EXT,
      BASE + "9gbQ7YR" + EXT, BASE + "aFhEEby" + EXT, BASE + "0E2tgV7" + EXT,
      BASE + "P5JLfjk" + EXT, BASE + "nz67a4F" + EXT, BASE + "dFH34N5" + EXT,
      BASE + "FI49ftb" + EXT, BASE + "DvpvklR" + EXT, BASE + "DNKnbG8" + EXT,
      BASE + "yAdbrLp" + EXT, BASE + "55w5Km7" + EXT, BASE + "NIwNTMR" + EXT,
      BASE + "DAl0KB8" + EXT, BASE + "xZLIYFV" + EXT, BASE + "HvTyeh3" + EXT,
      BASE + "Ig9oHCM" + EXT, BASE + "7GUv9qa" + EXT, BASE + "i5vXmXp" + EXT,
      BASE + "glyvuXg" + EXT, BASE + "u6JF6JZ" + EXT, BASE + "ExwR7ap" + EXT,
      BASE + "Q54zMKT" + EXT, BASE + "9t6hLbm" + EXT, BASE + "F8n3Ic6" + EXT,
      BASE + "P5ZRSvT" + EXT, BASE + "jbemFzr" + EXT, BASE + "8B7haIK" + EXT,
      BASE + "aSeTYQr" + EXT, BASE + "OKvWoTh" + EXT, BASE + "zD3gT4Z" + EXT,
      BASE + "z77CaIt" + EXT,
  };

  private ImageData() {
    // No instances.
  }
}

这是适配器行布局。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

  <ProgressBar
      android:id="@+id/progress"
      style="?android:progressBarStyle"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      tools:text="Hello World"
      />

  <ImageView
      android:id="@+id/image"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:contentDescription="@string/title_activity_loop_jasync"
      />

</LinearLayout>

主要布局。

<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/my_list_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.yelinaung.playground.LoopJAsync"
    />

如果可能的话，我想提出的建议之一就是使用图像加载库。他们可以优雅地处理图像下载和缓存。仅举几例，这些是受欢迎的。

Loopj AsyncHttpClient - 控制ArrayAdapter中处理程序的视图

1 个答案: