1

我是 Android 和 Java 的新手。我有 36 张图片的 URL。我想下载所有这些图像并在网格视图中显示它们。我指的是下面的代码，所以请如果有人可以编辑此代码以下载多个图像。并在网格视图中显示。 下面的代码只是获取一个 URL 并从该 URL 下载图像。

package com.example.androidhive;

import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;

import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class AndroidDownloadFileByProgressBarActivity extends Activity {

// button to show progress dialog
Button btnShowProgress;

// Progress Dialog
private ProgressDialog pDialog;
ImageView my_image;
// Progress dialog type (0 - for Horizontal progress bar)
public static final int progress_bar_type = 0; 

// File url to download
private static String file_url = "http://api.androidhive.info/progressdialog/hive.jpg";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // show progress bar button
    btnShowProgress = (Button) findViewById(R.id.btnProgressBar);
    // Image view to show image after downloading
    my_image = (ImageView) findViewById(R.id.my_image);
    /**
     * Show Progress bar click event
     * */
    btnShowProgress.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // starting new Async Task
            new DownloadFileFromURL().execute(file_url);
        }
    });
}

/**
 * Showing Dialog
 * */
@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
    case progress_bar_type: // we set this to 0
        pDialog = new ProgressDialog(this);
        pDialog.setMessage("Downloading file. Please wait...");
        pDialog.setIndeterminate(false);
        pDialog.setMax(100);
        pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        pDialog.setCancelable(true);
        pDialog.show();
        return pDialog;
    default:
        return null;
    }
}

/**
 * Background Async Task to download file
 * */
class DownloadFileFromURL extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread
     * Show Progress Bar Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        showDialog(progress_bar_type);
    }

    /**
     * Downloading file in background thread
     * */
    @Override
    protected String doInBackground(String... f_url) {
        int count;
        try {
            URL url = new URL(f_url[0]);
            URLConnection conection = url.openConnection();
            conection.connect();
            // this will be useful so that you can show a tipical 0-100% progress bar
            int lenghtOfFile = conection.getContentLength();

            // download the file
            InputStream input = new BufferedInputStream(url.openStream(), 8192);

            // Output stream
            OutputStream output = new FileOutputStream("/sdcard/downloadedfile.jpg");

            byte data[] = new byte[1024];

            long total = 0;

            while ((count = input.read(data)) != -1) {
                total += count;
                // publishing the progress....
                // After this onProgressUpdate will be called
                publishProgress(""+(int)((total*100)/lenghtOfFile));

                // writing data to file
                output.write(data, 0, count);
            }

            // flushing output
            output.flush();

            // closing streams
            output.close();
            input.close();

        } catch (Exception e) {
            Log.e("Error: ", e.getMessage());
        }

        return null;
    }

    /**
     * Updating progress bar
     * */
    protected void onProgressUpdate(String... progress) {
        // setting progress percentage
        pDialog.setProgress(Integer.parseInt(progress[0]));
   }

    /**
     * After completing background task
     * Dismiss the progress dialog
     * **/
    @Override
    protected void onPostExecute(String file_url) {
        // dismiss the dialog after the file was downloaded
        dismissDialog(progress_bar_type);

        // Displaying downloaded image into image view
        // Reading image path from sdcard
        String imagePath = Environment.getExternalStorageDirectory().toString() + "/downloadedfile.jpg";
        // setting downloaded into image view
        my_image.setImageDrawable(Drawable.createFromPath(imagePath));
    }

}
}

请帮忙

4

1 回答 1

0

我认为你应该使用通用图像加载器在 gridview 中显示图像。它完美无缺！！！

于 2012-11-05T06:15:28.060 回答