我正在处理我正在下载图片的壁纸应用程序，但现在我想在下载图像时显示下载过程。
我想要的是：请参阅此屏幕截图： http://www.techfeb.com/wp-content/uploads/2012/03/download-facebook-photos-on-android-smartphone-2.jpg
这是我的代码：
Utils.java
package info.androidhive.awesomewallpapers.util;
import info.androidhive.awesomewallpapers.R;
import java.io.File;
import java.io.FileOutputStream;
import java.util.Random;
import android.annotation.SuppressLint;
import android.app.WallpaperManager;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Point;
import android.os.Environment;
import android.util.Log;
import android.view.Display;
import android.view.WindowManager;
import android.widget.Toast;
@SuppressLint("NewApi")
public class Utils {
private String TAG = Utils.class.getSimpleName();
private Context _context;
private PrefManager pref;
// constructor
public Utils(Context context) {
this._context = context;
pref = new PrefManager(_context);
}
/*
* getting screen width
*/
@SuppressWarnings("deprecation")
public int getScreenWidth() {
int columnWidth;
WindowManager wm = (WindowManager) _context
.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
final Point point = new Point();
try {
display.getSize(point);
} catch (java.lang.NoSuchMethodError ignore) {
// Older device
point.x = display.getWidth();
point.y = display.getHeight();
}
columnWidth = point.x;
return columnWidth;
}
public void saveImageToSDCard(Bitmap bitmap) {
String dirname = "/Amazing Wallpapers/";
File myDir = new File(Environment
.getExternalStorageDirectory().getPath() + dirname);
myDir.mkdirs();
Random generator = new Random();
int n = 10000;
n = generator.nextInt(n);
String fname = "Wallpaper-" +n+".jpg";
File file = new File(myDir, fname);
if (file.exists())
file.delete();
try {
FileOutputStream out = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
out.flush();
out.close();
Toast.makeText(
_context,
_context.getString(R.string.toast_saved).replace("#",
"\"" + pref.getGalleryName() + "\""),
Toast.LENGTH_LONG).show();
Log.d(TAG, "Wallpaper saved to:" + file.getAbsolutePath());
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(_context,
_context.getString(R.string.toast_saved_failed),
Toast.LENGTH_SHORT).show();
}
}
public void setAsWallpaper(Bitmap bitmap) {
try {
WallpaperManager wm = WallpaperManager.getInstance(_context);
wm.setBitmap(bitmap);
Toast.makeText(_context,
_context.getString(R.string.toast_wallpaper_set),
Toast.LENGTH_SHORT).show();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(_context,
_context.getString(R.string.toast_wallpaper_set_failed),
Toast.LENGTH_SHORT).show();
}
}
}
FullScreenActivity.java
package info.androidhive.awesomewallpapers;
import info.androidhive.awesomewallpapers.app.AppController;
import info.androidhive.awesomewallpapers.picasa.model.Wallpaper;
import info.androidhive.awesomewallpapers.util.Utils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Point;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.ProgressBar;
import android.widget.Toast;
import com.android.volley.Request.Method;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.ImageLoader.ImageContainer;
import com.android.volley.toolbox.ImageLoader.ImageListener;
import com.android.volley.toolbox.JsonObjectRequest;
public class FullScreenViewActivity extends Activity implements OnClickListener {
private static final String TAG = FullScreenViewActivity.class
.getSimpleName();
public static final String TAG_SEL_IMAGE = "selectedImage";
private Wallpaper selectedPhoto;
private ImageView fullImageView;
private LinearLayout llSetWallpaper, llDownloadWallpaper;
private Utils utils;
private ProgressBar pbLoader;
// Picasa JSON response node keys
private static final String TAG_ENTRY = "entry",
TAG_MEDIA_GROUP = "media$group",
TAG_MEDIA_CONTENT = "media$content", TAG_IMG_URL = "url",
TAG_IMG_WIDTH = "width", TAG_IMG_HEIGHT = "height";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fullscreen_image);
fullImageView = (ImageView) findViewById(R.id.imgFullscreen);
llSetWallpaper = (LinearLayout) findViewById(R.id.llSetWallpaper);
llDownloadWallpaper = (LinearLayout) findViewById(R.id.llDownloadWallpaper);
pbLoader = (ProgressBar) findViewById(R.id.pbLoader);
// hide the action bar in fullscreen mode
getActionBar().hide();
utils = new Utils(getApplicationContext());
// layout click listeners
llSetWallpaper.setOnClickListener(this);
llDownloadWallpaper.setOnClickListener(this);
// setting layout buttons alpha/opacity
llSetWallpaper.getBackground().setAlpha(70);
llDownloadWallpaper.getBackground().setAlpha(70);
Intent i = getIntent();
selectedPhoto = (Wallpaper) i.getSerializableExtra(TAG_SEL_IMAGE);
// check for selected photo null
if (selectedPhoto != null) {
// fetch photo full resolution image by making another json request
fetchFullResolutionImage();
} else {
Toast.makeText(getApplicationContext(),
getString(R.string.msg_unknown_error), Toast.LENGTH_SHORT)
.show();
}
}
/**
* Fetching image fullresolution json
* */
private void fetchFullResolutionImage() {
String url = selectedPhoto.getPhotoJson();
// show loader before making request
pbLoader.setVisibility(View.VISIBLE);
llSetWallpaper.setVisibility(View.GONE);
llDownloadWallpaper.setVisibility(View.GONE);
// volley's json obj request
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Method.GET, url,
null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d(TAG,
"Image full resolution json: "
+ response.toString());
try {
// Parsing the json response
JSONObject entry = response
.getJSONObject(TAG_ENTRY);
JSONArray mediacontentArry = entry.getJSONObject(
TAG_MEDIA_GROUP).getJSONArray(
TAG_MEDIA_CONTENT);
JSONObject mediaObj = (JSONObject) mediacontentArry
.get(0);
String fullResolutionUrl = mediaObj
.getString(TAG_IMG_URL);
// image full resolution widht and height
final int width = mediaObj.getInt(TAG_IMG_WIDTH);
final int height = mediaObj.getInt(TAG_IMG_HEIGHT);
Log.d(TAG, "Full resolution image. url: "
+ fullResolutionUrl + ", w: " + width
+ ", h: " + height);
ImageLoader imageLoader = AppController
.getInstance().getImageLoader();
// We download image into ImageView instead of
// NetworkImageView to have callback methods
// Currently NetworkImageView doesn't have callback
// methods
imageLoader.get(fullResolutionUrl,
new ImageListener() {
@Override
public void onErrorResponse(
VolleyError arg0) {
Toast.makeText(
getApplicationContext(),
getString(R.string.msg_wall_fetch_error),
Toast.LENGTH_LONG).show();
}
@Override
public void onResponse(
ImageContainer response,
boolean arg1) {
if (response.getBitmap() != null) {
// load bitmap into imageview
fullImageView
.setImageBitmap(response
.getBitmap());
adjustImageAspect(width, height);
// hide loader and show set &
// download buttons
pbLoader.setVisibility(View.GONE);
llSetWallpaper
.setVisibility(View.VISIBLE);
llDownloadWallpaper
.setVisibility(View.VISIBLE);
}
}
});
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(),
getString(R.string.msg_unknown_error),
Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Error: " + error.getMessage());
// unable to fetch wallpapers
// either google username is wrong or
// devices doesn't have internet connection
Toast.makeText(getApplicationContext(),
getString(R.string.msg_wall_fetch_error),
Toast.LENGTH_LONG).show();
}
});
// Remove the url from cache
AppController.getInstance().getRequestQueue().getCache().remove(url);
// Disable the cache for this url, so that it always fetches updated
// json
jsonObjReq.setShouldCache(false);
// Adding request to request queue
AppController.getInstance().addToRequestQueue(jsonObjReq);
}
/**
* Adjusting the image aspect ration to scroll horizontally, Image height
* will be screen height, width will be calculated respected to height
* */
@SuppressWarnings("deprecation")
@SuppressLint("NewApi")
private void adjustImageAspect(int bWidth, int bHeight) {
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
if (bWidth == 0 || bHeight == 0)
return;
int sHeight = 0;
if (android.os.Build.VERSION.SDK_INT >= 13) {
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
sHeight = size.y;
} else {
Display display = getWindowManager().getDefaultDisplay();
sHeight = display.getHeight();
}
int new_width = (int) Math.floor((double) bWidth * (double) sHeight
/ (double) bHeight);
params.width = new_width;
params.height = sHeight;
Log.d(TAG, "Fullscreen image new dimensions: w = " + new_width
+ ", h = " + sHeight);
fullImageView.setLayoutParams(params);
}
/**
* View click listener
* */
@Override
public void onClick(View v) {
Bitmap bitmap = ((BitmapDrawable) fullImageView.getDrawable())
.getBitmap();
switch (v.getId()) {
// button Download Wallpaper tapped
case R.id.llDownloadWallpaper:
utils.saveImageToSDCard(bitmap);
break;
// button Set As Wallpaper tapped
case R.id.llSetWallpaper:
utils.setAsWallpaper(bitmap);
break;
default:
break;
}
}
}
答案 0 :(得分：0)
这是一个非常好的教程..
http://www.androidbegin.com/tutorial/android-download-image-from-url/ \ 该网站代码的片段如下：
private class DownloadImage extends AsyncTask<String, Void, Bitmap> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Create a progressdialog
mProgressDialog = new ProgressDialog(MainActivity.this);
// Set progressdialog title
mProgressDialog.setTitle("Download Image Tutorial");
// Set progressdialog message
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Bitmap doInBackground(String... URL) {
String imageURL = URL[0];
Bitmap bitmap = null;
try {
// Download Image from URL
InputStream input = new java.net.URL(imageURL).openStream();
// Decode Bitmap
bitmap = BitmapFactory.decodeStream(input);
} catch (Exception e) {
e.printStackTrace();
}
return bitmap;
}
@Override
protected void onPostExecute(Bitmap result) {
// Set the bitmap into ImageView
image.setImageBitmap(result);
// Close progressdialog
mProgressDialog.dismiss();
}
}
答案 1 :(得分：0)
您可以在onCreate方法中使用ProgressDialog。
mProgressDialog = new ProgressDialog(YourActivity.this);
然后您可以添加其他属性，如消息等，如下所示：
mProgressDialog.setMessage("A message");
你也可以像这样添加听众：
mProgressDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
@Override
public void onCancel(DialogInterface dialog) {
// Do stuff on Cancel
}
});
检查此链接：
Download a file with Android, and showing the progress in a ProgressDialog