问题
This is a question about image saving in android app. I am trying to make popular movies app of an udacity project.Link - https://docs.google.com/document/d/1gtXUu1nzLGWrGfVCD6tEA0YHoYA9UNyT2yByqjJemp8/pub?embedded=true
I have picasso library for image downloading in ImageAdapter--
Here is my ImageAdapter code -
package jindal5.mayank.popular_movies_14ce10032_gsc;
public class ImageAdapter extends BaseAdapter {
private String drawablePrefix;
private Context mContext;
private ArrayList<String> mThumbUris;
private ArrayList<String> mov_id_arr;
private ArrayList<String> mov_tit_arr;
public ImageAdapter(Context c) {
mContext = c;
String packName=mContext.getPackageName();
drawablePrefix="android.resource://" +packName+ "/";
ArrayList<String> mov_id_arr =new ArrayList<>();
ArrayList<String> mov_tit_arr=new ArrayList<>();
mov_tit_arr.add("asdf");
mov_tit_arr.add("asdf");
mov_tit_arr.add("asdf");
mov_tit_arr.add("asdf");
mov_tit_arr.add("asdf");
mov_tit_arr.add("asdf");
ArrayList<String> uriPaths=new ArrayList<>();// place your drawables.
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
mThumbUris=uriPaths;
}
public int getCount() {
return mThumbUris.size();
}
public Object getItem(int position) {
return mThumbUris.get(position);
}
public long getItemId(int position) {
return 0;
}
// create a new ImageView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
// if it's not recycled, initialize some attributes
imageView = new ImageView(mContext);
// imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
// imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
// imageView.setPadding(8, 8, 8, 8);
} else {
imageView = (ImageView) convertView;
}
Uri imgUri=Uri.parse(mThumbUris.get(position));
Picasso.with(mContext)
.load(imgUri)
.placeholder(R.drawable.sample_0)
.centerCrop()
.resize(400,400)
.into(imageView);
imageView.setImageResource(mThumbIds[position]);
// imageView.setAdjustViewBounds(true);
return imageView;
}
public ArrayList<String> getUriList(){
return mThumbUris;
}
public ArrayList<String> getidlist(){
return mov_id_arr;
}
public ArrayList<String> gettitlist(){
return mov_tit_arr;
}
// references to our images
private Integer[] mThumbIds = {
R.drawable.sample_2, R.drawable.sample_3,
R.drawable.sample_4, R.drawable.sample_5,
R.drawable.sample_6, R.drawable.sample_7,
R.drawable.sample_0, R.drawable.sample_1,
R.drawable.sample_2, R.drawable.sample_3,
R.drawable.sample_4, R.drawable.sample_5,
R.drawable.sample_6, R.drawable.sample_7,
R.drawable.sample_0, R.drawable.sample_1,
R.drawable.sample_2, R.drawable.sample_3,
R.drawable.sample_4, R.drawable.sample_5,
R.drawable.sample_6, R.drawable.sample_7
};
}
Now I have two problems -
- When I return back to Main Activity from another activity ,local images appear rather than previously downloading images.
- When I close my app and open again I see the local images appear rather than downloaded images at last time. Somebody told that you have to save that images after downloading in local memory using File or content provider. But I don't know how to do that ?? .
3.When I change my device orientation I face the same problem.
This is my fragment of main activity-
package jindal5.mayank.popular_movies_14ce10032_gsc;
/**
* A placeholder fragment containing a simple view.
*/
public class MainActivityFragment extends Fragment {
public ImageAdapter imag_adap;
public String movieJsonStr;
public ArrayList<String > tit_arr = new ArrayList<String>();
public ArrayList<String > rel_dat_arr = new ArrayList<String>();
public ArrayList<String > url1_arr = new ArrayList<String>();
public ArrayList<String > over_arr = new ArrayList<String>();
public ArrayList<String > id_arr = new ArrayList<String>();
public String put_ext_tit;
public String rel_date_ext;
public String url_for_pos_ex;
public String over_ex;
public String id_ex;
public MainActivityFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Add this line in order for this fragment to handle menu events.
setHasOptionsMenu(true);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.menu_fragment, menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_refresh) {
//SharedPreferences share = PreferenceManager.getDefaultSharedPreferences();
// String order = share.getString()
getimage imageTask = new getimage();
imageTask.execute("popularity.desc");
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootview = inflater.inflate(R.layout.fragment_main, container, false);
GridView grid = (GridView) rootview.findViewById(R.id.gridView);
imag_adap = new ImageAdapter(getActivity());
grid.setAdapter(imag_adap);
grid.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
String[] tit1 = tit_arr.toArray(new String[tit_arr.size()]);
String[] rel_date = rel_dat_arr.toArray(new String[rel_dat_arr.size()]);
String[] url_for_pos = url1_arr.toArray(new String[url1_arr.size()]);
String[] over = url1_arr.toArray(new String[over_arr.size()]);
String[] id = id_arr.toArray(new String[over_arr.size()]);
// Log.v("mayank",tit1[3]);
try{
put_ext_tit = tit1[i];
rel_date_ext = rel_date[i];
url_for_pos_ex = url_for_pos[i];
over_ex = over[i];
id_ex =id[i];
Intent intent = new Intent(getActivity(),det_mov.class);
//.putExtra(Intent.EXTRA_TEXT,put_ext_tit);
Bundle extras = new Bundle();
extras.putString("title",put_ext_tit);
extras.putString("rel_date",rel_date_ext);
extras.putString("url_pos",url_for_pos_ex);
extras.putString("over_ex",over_ex);
extras.putString("id_ex", id_ex);
extras.putInt("posit",i);
intent.putExtras(extras);
startActivity(intent);
}
catch (ArrayIndexOutOfBoundsException p){
Log.e("mayank","reg",p);
}
}
});
return rootview;
}
public class getimage extends AsyncTask<String, String, String[]> {
ConnectivityManager conMgr = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
private final String LOG_TAG = getimage.class.getSimpleName();
public int count;
String[] pos_path;
String[] mov_id;
String[] tit;
String[] rev;
String[] rel_dat;
String[] url1;
String[] over;
String[] id;
public ImageAdapter getad(){
return imag_adap;
}
@Override
protected String[] doInBackground(String... params) {
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
try {
final String movie_url_str = "http://api.themoviedb.org/3/discover/movie?sort_by="+ params[0] +"&api_key=8d7a48043ba1d3348181e2b6615cedc7";
URL movie_url = new URL(movie_url_str);
urlConnection = (HttpURLConnection) movie_url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
return null;
}
movieJsonStr = buffer.toString();
JSONObject movieJson = new JSONObject(movieJsonStr);
JSONArray movieJsonarray = movieJson.getJSONArray("results");
count = movieJsonarray.length();
pos_path = new String[count];
mov_id = new String[count];
tit = new String[count];
rev = new String[count];
rel_dat = new String[count];
url1 = new String[count];
over = new String[count];
id = new String[count];
for(int i=0;i<count;i++){
JSONObject sin_movie = movieJsonarray.getJSONObject(i);
pos_path[i] = sin_movie.getString("poster_path");
over[i] = sin_movie.getString("overview");
Uri.Builder url_for_poster = new Uri.Builder();
String qw = "t";
String as = "p";
Uri.Builder url_build = url_for_poster.scheme("http").authority("image.tmdb.org").appendPath(qw).appendPath(as).appendPath("w500").appendEncodedPath(pos_path[i]);
url1[i] = url_build.toString();
// mov_id[i] = sin_movie.getString("id");
tit[i] = sin_movie.getString("title");
//rev[i] = sin_movie.getString("review");
rel_dat[i] = sin_movie.getString("release_date");
id[i] = sin_movie.getString("id");
publishProgress((String)(tit[i]),(String)(rel_dat[i]),(String)(url1[i]),(String)(over[i]),(String)(id[i]));
Log.v(LOG_TAG, "Forecast string: " + id[i]);
}
} catch (IOException | JSONException e) {
Log.e(LOG_TAG, "Error ", e);
return null;
}
finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e(LOG_TAG, "Error closing stream", e);
}
}
}
return pos_path;
}
@Override
protected void onProgressUpdate(String... values) {
tit_arr.add(values[0]);
rel_dat_arr.add(values[1]);
url1_arr.add(values[2]);
over_arr.add(values[3]);
id_arr.add(values[4]);
}
@Override
protected void onPostExecute(String[] result) {
ArrayList<String> uriPaths = imag_adap.getUriList();
uriPaths.clear();
// ImageView[] im_vi = new ImageView[count];
for(int j=0;j<count;j++) {
String pos_sin_path = pos_path[j];
String id_mov = id[j];
Uri.Builder url_for_poster = new Uri.Builder();
Uri.Builder url_for_rev = new Uri.Builder();
String qw = "t";
String as = "p";
Uri.Builder url_build = url_for_poster.scheme("http").authority("image.tmdb.org").appendPath(qw).appendPath(as).appendPath("w500").appendEncodedPath(pos_sin_path);
String url = url_build.toString();
Uri.Builder url_build_rev = url_for_rev.scheme("http").encodedAuthority("api.themoviedb.org/3/movie").appendPath(id_mov).appendPath("reviews");
uriPaths.add(url);
// mov_title.add(tit[j]);
//mov_id_arr.add(id);
// mov_tit_arr.add(title);
// }
//catch (UnsupportedEncodingException e){
//}
//url_build.clearQuery();
//Picasso.with(getActivity()).load("http://image.tmdb.org/t/p/w185//nBNZadXqJSdt05SHLqgT0HuC5Gm.jpg").into(im_vi[j]);
//imag_adap.getItem(j) = im_vi[j];\
}
imag_adap.notifyDataSetChanged();
}
}
}
Looking for a help As I am new in android.
回答1:
When I close my app and open again I see the local images appear rather than downloaded images at last time. Somebody told that you have to save that images after downloading in local memory using File or content provider. But I don't know how to do that ?? .
This is expected since you do not have the photos anywhere on your device.Save the image in a database (SQLite) If you want it persisted and available when you return to your app. Or you load them each time you restart your activity, preferably through an AsyncTask.
To store images in the SQLite database, take a look at How to store(bitmap image) and retrieve image from sqlite database in android? Tells you everything you need to know about saving and retrieving images.
回答2:
try this,
answer-1:
try to change adapter initialization logic to onCreateView to onCreate. put this line in onCreate.
imag_adap = new ImageAdapter(getActivity());
answer-2:
after download images save that uri paths in database or file or in sharedpreference. and then retrieve that uri's in creation adapter.
ArrayList<String> uriPathsFromDb=getListOfUriFromDatabase();
if(uriPathsFromDb.size()==0){
ArrayList<String> uriPaths=new ArrayList<>();// place your drawables.
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
uriPaths.add(drawablePrefix+ R.drawable.sample_0);
mThumbUris=uriPaths;
}else{
mThumbUris=uriPathsFromDb;
}
来源：https://stackoverflow.com/questions/31267286/save-images-locally-in-image-adapter-in-android