Question

我是android新手。我需要下载一个图像并在活动中显示该图像。我尝试了更多我无法得到输出。有人可以帮帮我吗？

public class Home_Appliances extends AppCompatActivity {
private static final String TAG = Home_Appliances.class.getSimpleName();

// Movies json url
private static final String url = "http://quickiz.com/abdullah/json/pickspage?commonId=125";

private ProgressDialog pDialog;
private List<City> cityList = new ArrayList<City>();
private ListView listView;
private CustomListAdapter adapter;

private TextView textView;
private BroadcastReceiver receiver = new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {
        Bundle bundle = intent.getExtras();
        if (bundle != null) {
            String string = bundle.getString(DownloadService.FILEPATH);
            int resultCode = bundle.getInt(DownloadService.RESULT);
            if (resultCode == RESULT_OK) {
                Toast.makeText(Home_Appliances.this,
                        "Download complete. Download URI: " + string,
                        Toast.LENGTH_LONG).show();
                textView.setText("Download done");
            } else {
                Toast.makeText(Home_Appliances.this, "Download failed",
                        Toast.LENGTH_LONG).show();
                textView.setText("Download failed");
            }
        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home__appliances);
    textView = (TextView) findViewById(R.id.status);

    listView = (ListView) findViewById(R.id.list);
    /*adapter = new CustomListAdapter(this, cityList);
    listView.setAdapter(adapter);*/
    pDialog = new ProgressDialog(this);

    pDialog.setMessage("Loading...");
    pDialog.show();
    JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
            url,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    Log.d(TAG, response.toString());
                    hidePDialog();
                    JSONArray jsonarr = null;
                    try {
                        jsonarr = response.getJSONArray("productDetails");
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                    for (int i = 0; i < jsonarr.length(); i++) {


                        JSONObject obj = null;
                        try {
                            obj = jsonarr.getJSONObject(i);

                            City city = new City();
                            city.setTitle(obj.getString("productName"));
                            city.setThumbnailUrl(obj.getString("Image"));

                            // adding movie to movies array
                            cityList.add(city);


                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }

                    //adapter.notifyDataSetChanged();
                }
            }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d(TAG, "Error: " + error.getMessage());
            pDialog.hide();
        }
    });

    // Adding request to request queue
    AppController.getInstance().addToRequestQueue(jsonObjReq);

}

public void onDestroy() {
    super.onDestroy();
    hidePDialog();
}

private void hidePDialog() {
    if (pDialog != null) {
        pDialog.dismiss();
        pDialog = null;
    }
}

protected void onResume() {
    super.onResume();
    registerReceiver(receiver, new IntentFilter(
            DownloadService.NOTIFICATION));
}
@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(receiver);
}

public void onClick(View view) {



    Intent intent = new Intent(this, DownloadService.class);
    // add infos for the service which file to download and where to store
    intent.putExtra(DownloadService.FILENAME, "MyImages");
    intent.putExtra(DownloadService.URL,cityList.get(0).getThumbnailUrl());
    startService(intent);
    textView.setText("Service started");
    System.out.println("-----URL image---------"+cityList.get(0).getThumbnailUrl());
}
}

这是我的服务类

public class DownloadService extends IntentService {

private int result = Activity.RESULT_CANCELED;
public static final String URL = "urlpath";
public static final String FILENAME = "filename";
public static final String FILEPATH = "filepath";
public static final String RESULT = "result";
public static final String NOTIFICATION = "com.vogella.android.service.receiver";

public DownloadService() {
    super("DownloadService");
}

// will be called asynchronously by Android
@Override
protected void onHandleIntent(Intent intent) {
    String urlPath = intent.getStringExtra(URL);
    System.out.println("urlpath=================================>"+urlPath);
    String fileName = intent.getStringExtra(FILENAME);
    File output = new File(Environment.getExternalStorageDirectory(),
            fileName);
    if (output.exists()) {
        output.delete();
        System.out.println("am in download if class=============================>");
    }

    InputStream stream = null;
    FileOutputStream fos = null;
    try {

       URL url = new URL(urlPath);
        stream = url.openConnection().getInputStream();
        InputStreamReader reader = new InputStreamReader(stream);
        fos = new FileOutputStream(output.getPath());
        int next = -1;
        while ((next = reader.read()) != -1) {
            fos.write(next);
        }
        // successfully finished
        result = Activity.RESULT_OK;

    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (stream != null) {
            try {
                stream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (fos != null) {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    publishResults(output.getAbsolutePath(), result);
}

private void publishResults(String outputPath, int result) {
    Intent intent = new Intent(NOTIFICATION);
    intent.putExtra(FILEPATH, outputPath);
    intent.putExtra(RESULT, result);
    sendBroadcast(intent);
}
}

Answer 1

创建一个图像视图来保存图像，然后使用Picasso下载并在imageview中插入图像。查看毕加索图书馆的广场。

在Gradle中添加以下行：

compile 'com.squareup.picasso:picasso:2.5.2'

然后在您的活动中：Picasso.with(context).load("YourURL").into(imageView);

imageView是您希望它显示在您的imageview。

使用服务下载图像

1 个答案: