我是制作Android应用程序的新手。我正在尝试创建一个简单的应用程序，从themoviedb.org提取电影数据，并在主页上显示电影中的海报。我正在使用带有自定义适配器的GridView和ImageView，但屏幕显示为空白。我不确定我需要做些什么才能让图像显示出来。
自定义适配器：
public class CustomImageAdapter extends BaseAdapter {
private Context mContext;
private String[] inputs;
private List<ImageView> imageList;
LayoutInflater inflater;
public CustomImageAdapter(Context c, String[] inputs) {
mContext = c;
this.inputs = inputs;
inflater = (LayoutInflater) this.mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public int getCount() {
return inputs.length;
}
public Object getItem(int position) {
return imageList.get(position);
}
public long getItemId(int position) {
return position;
}
public void add(String[] results) {
inputs = results;
imageList = new ArrayList<ImageView>();
for (int i = 0; i < inputs.length; i++){
ImageView imageView = new ImageView(mContext);
Picasso.with(mContext)
.load(inputs[i])
.into(imageView);
imageList.add(imageView);
}
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View gridView;
if (convertView == null) {
gridView = new View(mContext);
convertView = inflater.inflate(R.layout.grid_layout, null);
ImageView imageView = (ImageView) gridView.findViewById(R.id.grid_layout_image_view);
imageView = imageList.get(position);
} else {
gridView = (View) convertView;
}
return gridView;
}
}
主要片段：
public class GridFragment extends Fragment {
private static ImageView imageView;
private static String[] jsonStringHolder = new String[1];
private static CustomImageAdapter customImageAdapter;
private static GridView gridView;
public GridFragment() {
}
@Override
public void onStart() {
super.onStart();
FetchMovieTask fetchMovieTask = new FetchMovieTask();
fetchMovieTask.execute();
}
private void loadImageView(String[] result) {
try {
getMovieDataFromJson(result);
} catch (JSONException e) {
Log.e("LOG_TAG", e.getMessage(), e);
e.printStackTrace();
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
//customImageAdapter = new CustomImageAdapter(getContext(), null);
gridView = (GridView) rootView.findViewById(R.id.grid_view);
//gridView.setAdapter(customImageAdapter);
return rootView;
}
private void getMovieDataFromJson(String[] jsonStringHolder)
throws JSONException {
final String OWM_POSTER_PATH = "poster_path";
final String OWM_RESULTS = "results";
String movieJsonStr = jsonStringHolder[0];
JSONObject movieJsonObject = new JSONObject(movieJsonStr);
JSONArray movieJsonArray = movieJsonObject.getJSONArray(OWM_RESULTS);
String[] resultStrs = new String[movieJsonArray.length()];
for (int i = 0; i < movieJsonArray.length(); i++) {
JSONObject movieDescriptionJsonObject = movieJsonArray.getJSONObject(i);
String posterPathPlaceholder =
movieDescriptionJsonObject.getString(OWM_POSTER_PATH);
final String FORECAST_BASE_URL =
"http://api.themoviedb.org/3/movie/";
final String SIZE = "w185";
resultStrs[i] = FORECAST_BASE_URL + SIZE + posterPathPlaceholder;
}
customImageAdapter = new CustomImageAdapter(getContext(), null);
customImageAdapter.add(resultStrs);
gridView.setAdapter(customImageAdapter);
}
public class FetchMovieTask extends AsyncTask<Void, Void, String[]> {
private final String LOG_TAG = FetchMovieTask.class.getSimpleName();
@Override
protected String[] doInBackground(Void... params) {
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
// Will contain the raw JSON response as a string.
String movieJsonStr = null;
// String format = "json";
//String units = "metric";
//int numDays = 7;
try {
// Construct the URL for the OpenWeatherMap query
// Possible parameters are avaiable at OWM's forecast API page, at
// http://openweathermap.org/API#forecast
final String FORECAST_BASE_URL =
"http://api.themoviedb.org/3/movie/";
final String PREFERENCE = "now_playing?";
final String API_KEY = "api_key=e0cbb327025cf835dfc53ca51d11db68";
//final String UNITS_PARAM = "units";
//final String DAYS_PARAM = "cnt";
String urlString = FORECAST_BASE_URL + PREFERENCE + API_KEY;
URL url = new URL(urlString);
// Create the request to OpenWeatherMap, and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
movieJsonStr = buffer.toString();
} catch (IOException e) {
Log.e(LOG_TAG, "Error pits", e);
// If the code didn't successfully get the weather data, there's no point in attemping
// to parse it.
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);
}
}
}
String[] movieJsonStrArray = new String[1];
movieJsonStrArray[0] = movieJsonStr;
return movieJsonStrArray;
}
@Override
protected void onPostExecute(String[] result) {
if (result != null) {
jsonStringHolder[0] = result[0];
}
loadImageView(result);
}
}
XML：
<RelativeLayout 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=".MainActivityFragment">
<GridView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/grid_view"
android:layout_alignParentBottom="true"
android:layout_centerInParent="true">
</GridView>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/grid_layout_image_view" />
</RelativeLayout>
答案 0 :(得分：0)
如果你试图用行填充列表，并且你是android的新手，也许你应该尝试从ListActivity或FragmentList扩展，请参阅http://developer.android.com/guide/topics/ui/layout/listview.html的google指南，ListActivity和FragmentList是帮手clases，他们有一个方法＆＃34; setListAdapter＆＃34;这样做。