毕加索图像不能在GridView的装载Android版 [英] Picasso Images are not loading in Gridview Android
本文介绍了毕加索图像不能在GridView的装载Android版的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我一直在拍电影应用程序（用于学习上udacity机器人BTW项目工作）。我遇到了一些问题，但按照线程这类<解决他们href=\"http://stackoverflow.com/questions/3200551/unable-to-modify-arrayadapter-in-listview-unsupportedoperationexception\">Unable修改ArrayAdapter中的ListView：UnsupportedOperationException异常
不过，虽然我的应用程序不会崩溃，图像不加载，我无法找出原因。这里是我的code：
布局XML文件movies_item.xml
＆LT;？XML版本=1.0编码=UTF-8＆GT？;
＆LT; ImageView的的xmlns：机器人=http://schemas.android.com/apk/res/android
机器人：layout_width =WRAP_CONTENT
机器人：layout_height =WRAP_CONTENT
机器人：ID =@ + ID / movies_item_thumbnail
＆GT;
＆LT; / ImageView的＆GT;
fragment_main.xml
＆LT;的FrameLayout的xmlns：机器人=http://schemas.android.com/apk/res/android
的xmlns：工具=http://schemas.android.com/tools的android：layout_width =match_parent
机器人：layout_height =match_parent机器人：paddingLeft =@扪/ activity_horizontal_margin
机器人：paddingRight =@扪/ activity_horizontal_margin
机器人：paddingTop =@扪/ activity_vertical_margin
机器人：paddingBottom会=@扪/ activity_vertical_margin
工具：上下文=com.example.cindy.popularmovies.MoviesFragment＆GT; ＆LT; GridView控件
机器人：ID =@ + ID / movies_gridview
机器人：layout_width =match_parent
机器人：layout_height =match_parent
机器人：为numColumns =auto_fit
机器人：比重=中心
/＆GT;＆LT; /＆的FrameLayout GT;
MovieArrayAdapter.java
公共类MovieArrayAdapter扩展ArrayAdapter＆LT;电影及GT; {
私人最终上下文的背景下;
私人最终名单＆LT;电影及GT;电影; 公共MovieArrayAdapter（上下文的背景下，列表与LT;电影＆GT;电影）{
超（背景下，0，电影）;
this.context =背景;
this.movies =电影;
} / *
*内getView（）方法，你能吹一个基于XML的布局和
*然后设置的基于Java对象该行对个人意见的内容。
* * / @覆盖
公共查看getView（INT位置，查看convertView，父母的ViewGroup）{ 查看rowView = convertView;
如果（rowView == NULL）{
//充气基于XML布局
LayoutInflater吹气=（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
rowView = inflater.inflate（R.layout.movies_item，父母，假）; //获取的ImageView
ImageView的movieThumbnail =（ImageView的）rowView.findViewById（R.id.movies_item_thumbnail）;
//加载图片到ImageView的
Picasso.with（上下文）.load（movies.get（位置）.getThumbnail（））到（movieThumbnail）。 Log.v（填充，movies.get（位置）.getThumbnail（））;
}
返回rowView;
} @覆盖
公众诠释的getCount（）{
返回super.getCount（）;
} @覆盖
公众诠释为getPosition（电影项目）{
返回super.getPosition（项目）;
}
}
MovieFragment.java公共类MoviesFragment扩展片段{ 私人MovieArrayAdapter mMoviesAdapter; 公共MoviesFragment（）{
} @覆盖
公共无效调用onStart（）{
super.onStart（）;
新FetchMoviesTask（）执行（）;
} @覆盖
公共查看onCreateView（LayoutInflater充气器，容器的ViewGroup，
捆绑savedInstanceState）{
查看rootView = inflater.inflate（R.layout.fragment_main，集装箱，FALSE）; mMoviesAdapter =新MovieArrayAdapter（getActivity（），新的ArrayList＆LT;电影及GT;（））; GridView控件moviesGridView =（GridView控件）rootView.findViewById（R.id.movies_gridview）;
moviesGridView.setAdapter（mMoviesAdapter）; 返回rootView;
} 公共类FetchMoviesTask扩展的AsyncTask＆LT;弦乐，太虚，电影[]＆GT; { 最后弦乐LOG_TAG = this.getClass（）getSimpleName（）。 @覆盖
保护电影[] doInBackground（字符串... PARAMS）{ //检索大众电影JSON字符串
串moviesJsonString = getMoviesJsonString（）; //解析JSON字符串来获得重要数据
尝试{
返回getPopularMoviesInfo（moviesJsonString）;
}赶上（JSONException E）{
Log.e（LOG_TAG，e.getMessage（），E）;
}
返回null;
} @覆盖
保护无效onPostExecute（动画[]电影）{
如果（电影！= NULL）{
mMoviesAdapter.clear（）;
mMoviesAdapter.addAll（电影）;
}
} / *
*此功能是从Web API获取热门电影JSON字符串
* * /
私人字符串getMoviesJsonString（）{
HttpURLConnection类的URLConnection = NULL;
的BufferedReader的BufferedReader = NULL;
字符串moviesJsonString = NULL; 尝试{ //设置的URI
最后弦乐MOVIES_BASE_URL =http://api.themoviedb.org/3/discover/movie？
最后弦乐SORT_PARAM =sort_by;
最后弦乐API_PARAM =API_KEY; 乌里moviesUri = Uri.parse（MOVIES_BASE_URL）.buildUpon（）
.appendQueryParameter（SORT_PARAMpopularity.desc）
.appendQueryParameter（API_PARAM，的getString（R.string.movies_api））
。建立（）; //打开连接
网址URL =新的URL（moviesUri.toString（））;
URLConnection的=（HttpURLConnection类）url.openConnection（）;
urlConnection.setRequestMethod（GET）;
urlConnection.connect（）; //读取输入流中的字符串
为InputStream的InputStream = urlConnection.getInputStream（）;
如果（InputStream的== NULL）{
返回null;
} 的BufferedReader =新的BufferedReader（新的InputStreamReader（InputStream的））; 串线;
StringBuffer的缓冲区=新的StringBuffer（）;
而（（行= bufferedReader.readLine（））！= NULL）{
buffer.append（行+\\ n）;
} 如果（buffer.length（）== 0）{
//流是空的
返回null;
} moviesJsonString = buffer.toString（）; }赶上（IOException异常五）{
Log.e（LOG_TAG，错误，E）;
} {最后
如果（URLConnection的！= NULL）{
urlConnection.disconnect（）;
}
如果（的BufferedReader！= NULL）{
尝试{
bufferedReader.close（）;
}赶上（IOException异常五）{
Log.e（LOG_TAG，错误收盘流，E）;
}
}
} 返回moviesJsonString;
} / *
*此功能是解析JSON字符串来检索信息
* * /
民营电影[] getPopularMoviesInfo（字符串jsonString）抛出JSONException { //缩略图的基本URL
最后弦乐THUMBNAIL_BASE_URL =http://image.tmdb.org/t/p/w185; //属性名，我们感兴趣的是JSON字符串
最后弦乐M_RESULTS =成果;
最后弦乐M_THUMBNAIL =backdrop_path;
最后弦乐M_TITLE =ORIGINAL_TITLE;
最后弦乐M_ID =ID;
最后弦乐M_SYPNOSIS =概览;
最后弦乐M_USER_RATING =vote_average;
最后弦乐M_RELEASE_DATE =RELEASE_DATE;
//转换JSON字符串以JSON对象
JSONObject的moviesJsonObject =新的JSONObject（jsonString）; //获取JSON数组
JSONArray moviesJsonArray = moviesJsonObject.getJSONArray（M_RESULTS）; 电影[] =电影新电影[moviesJsonArray.length（）];
的for（int i = 0; I＆LT; moviesJsonArray.length（）;我++）{
的JSONObject电影= moviesJsonArray.getJSONObject（ⅰ）; 电影由[i] =新电影（THUMBNAIL_BASE_URL + movie.getString（M_THUMBNAIL）
movie.getString（M_TITLE）
movie.getString（M_ID）
movie.getString（M_SYPNOSIS）
movie.getString（M_USER_RATING）
movie.getString（M_RELEASE_DATE））; Log.v（电影，movie.getString（M_TITLE））;
} 回归电影; }
}
}
有没有错误，但图像不加载。我一直在寻找在其他线程，但无法找到答案我的问题。非常感谢你。
根据下面的讨论[增订]更改了code：
@覆盖
公共查看getView（INT位置，查看convertView，父母的ViewGroup）{ 如果（convertView == NULL）{
//充气基于XML布局
LayoutInflater吹气=（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
convertView = inflater.inflate（R.layout.movies_item，父母，假）;
} //获取的ImageView
ImageView的movieThumbnail =（ImageView的）convertView.findViewById（R.id.movies_item_thumbnail）; //加载图片到ImageView的
Picasso.with（上下文）.load（movies.get（位置）.getThumbnail（））到（movieThumbnail）。 Log.v（填充，movies.get（位置）.getThumbnail（））; 返回convertView;
}
解决方案
这些行：
//获取的ImageView
ImageView的movieThumbnail =（ImageView的）rowView.findViewById（R.id.movies_item_thumbnail）; //加载图片到ImageView的
Picasso.with（上下文）.load（movies.get（位置）.getThumbnail（））到（movieThumbnail）。
去外面的如果（rowView == NULL）{
您总是会得到只有一个空 convertView ，你必须调用两行，而你正在更新/填充你的 GridView控件。此刻你应该看到遍地常存第一张图像。请不要忘了上网权限添加到清单
I have been making a Movie App (project work for learning android on udacity btw). I encountered a few problems but resolved them by following threads such as these Unable to modify ArrayAdapter in ListView: UnsupportedOperationException
However, although my app does not crash, the images are not loading and I cannot figure out why. Here is my code:
Layout XMl files movies_item.xml
<?xml version="1.0" encoding="utf-8"?>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id = "@+id/movies_item_thumbnail"
>
</ImageView>
fragment_main.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.example.cindy.popularmovies.MoviesFragment">
<GridView
android:id="@+id/movies_gridview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:numColumns="auto_fit"
android:gravity="center"
/>
</FrameLayout>
MovieArrayAdapter.java
public class MovieArrayAdapter extends ArrayAdapter<Movie> {
private final Context context;
private final List<Movie> movies;
public MovieArrayAdapter(Context context,List<Movie> movies) {
super(context,0,movies);
this.context = context;
this.movies = movies;
}
/*
* Within the getView() method you would inflate an XML based layout and
* then set the content of the individual views based on the Java object for this row.
* */
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView = convertView;
if(rowView == null) {
//Inflate the XML based Layout
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
rowView = inflater.inflate(R.layout.movies_item, parent, false);
//Get the ImageView
ImageView movieThumbnail = (ImageView) rowView.findViewById(R.id.movies_item_thumbnail);
//Load Image into the ImageView
Picasso.with(context).load(movies.get(position).getThumbnail()).into(movieThumbnail);
Log.v("Populating", movies.get(position).getThumbnail());
}
return rowView;
}
@Override
public int getCount() {
return super.getCount();
}
@Override
public int getPosition(Movie item) {
return super.getPosition(item);
}
}
MovieFragment.java
public class MoviesFragment extends Fragment {
private MovieArrayAdapter mMoviesAdapter;
public MoviesFragment() {
}
@Override
public void onStart() {
super.onStart();
new FetchMoviesTask().execute();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
mMoviesAdapter = new MovieArrayAdapter(getActivity(),new ArrayList<Movie>());
GridView moviesGridView = (GridView) rootView.findViewById(R.id.movies_gridview);
moviesGridView.setAdapter(mMoviesAdapter);
return rootView;
}
public class FetchMoviesTask extends AsyncTask<String,Void,Movie[]> {
final String LOG_TAG = this.getClass().getSimpleName();
@Override
protected Movie[] doInBackground(String...params) {
//Retrieve the Popular Movies Json String
String moviesJsonString = getMoviesJsonString();
//Parse the Json String to get important data
try {
return getPopularMoviesInfo(moviesJsonString);
} catch(JSONException e) {
Log.e(LOG_TAG,e.getMessage(),e);
}
return null;
}
@Override
protected void onPostExecute(Movie[] movies) {
if(movies != null) {
mMoviesAdapter.clear();
mMoviesAdapter.addAll(movies);
}
}
/*
* This Function is to retrieve the Popular movies Json String from a WEB API
* */
private String getMoviesJsonString() {
HttpURLConnection urlConnection = null;
BufferedReader bufferedReader = null;
String moviesJsonString = null;
try {
//Set up the URI
final String MOVIES_BASE_URL = "http://api.themoviedb.org/3/discover/movie?";
final String SORT_PARAM = "sort_by";
final String API_PARAM ="api_key";
Uri moviesUri = Uri.parse(MOVIES_BASE_URL).buildUpon()
.appendQueryParameter(SORT_PARAM, "popularity.desc")
.appendQueryParameter(API_PARAM,getString(R.string.movies_api))
.build();
//Open the connection
URL url = new URL(moviesUri.toString());
urlConnection = (HttpURLConnection)url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
//Read the input stream into a string
InputStream inputStream = urlConnection.getInputStream();
if(inputStream == null) {
return null;
}
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
StringBuffer buffer = new StringBuffer();
while((line = bufferedReader.readLine()) != null) {
buffer.append(line + "\n");
}
if(buffer.length() == 0){
//Stream was empty
return null;
}
moviesJsonString = buffer.toString();
}catch(IOException e) {
Log.e(LOG_TAG,"Error",e);
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if(bufferedReader != null) {
try {
bufferedReader.close();
} catch(IOException e) {
Log.e(LOG_TAG, "Error closing stream", e);
}
}
}
return moviesJsonString;
}
/*
* This function is to parse the JSON String to retrieve info
* */
private Movie[] getPopularMoviesInfo(String jsonString) throws JSONException{
//Base URL of thumbnail
final String THUMBNAIL_BASE_URL = " http://image.tmdb.org/t/p/w185";
//The attribute names we are interested in the JSON String
final String M_RESULTS = "results";
final String M_THUMBNAIL = "backdrop_path";
final String M_TITLE = "original_title";
final String M_ID = "id";
final String M_SYPNOSIS = "overview";
final String M_USER_RATING = "vote_average";
final String M_RELEASE_DATE = "release_date";
//Convert Json String to Json Object
JSONObject moviesJsonObject = new JSONObject(jsonString);
//Get the Json Array
JSONArray moviesJsonArray = moviesJsonObject.getJSONArray(M_RESULTS);
Movie[] movies = new Movie[moviesJsonArray.length()];
for(int i=0;i<moviesJsonArray.length();i++) {
JSONObject movie = moviesJsonArray.getJSONObject(i);
movies[i] = new Movie(THUMBNAIL_BASE_URL + movie.getString(M_THUMBNAIL),
movie.getString(M_TITLE),
movie.getString(M_ID),
movie.getString(M_SYPNOSIS),
movie.getString(M_USER_RATING),
movie.getString(M_RELEASE_DATE));
Log.v("Movie",movie.getString(M_TITLE));
}
return movies;
}
}
}
There is no error, but the images are not loading. I have been looking in other threads, but cannot find the answer to my problem. Thank you very much.
[UPDATED] Changed the code according to discussion below:
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null) {
//Inflate the XML based Layout
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.movies_item, parent, false);
}
//Get the ImageView
ImageView movieThumbnail = (ImageView) convertView.findViewById(R.id.movies_item_thumbnail);
//Load Image into the ImageView
Picasso.with(context).load(movies.get(position).getThumbnail()).into(movieThumbnail);
Log.v("Populating", movies.get(position).getThumbnail());
return convertView;
}
解决方案
those line:
//Get the ImageView
ImageView movieThumbnail = (ImageView) rowView.findViewById(R.id.movies_item_thumbnail);
//Load Image into the ImageView
Picasso.with(context).load(movies.get(position).getThumbnail()).into(movieThumbnail);
go outside the if(rowView == null) {
You will always get only one null convertView, and you have to call that two lines while you are updating/populating your GridView . At the moment you should see alway the first image over and over. Please don't forget to add the Internet permission to the manifest
这篇关于毕加索图像不能在GridView的装载Android版的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
