Android 如何将URL路径转换为图像并显示在列表视图上
根据我尝试搜索商店的位置，搜索结果显示在单元格的列表视图中。我正在从Google获取名称、地址、相关图标和评级，但问题是如何在列表单元格的列表视图上显示图像。我获取了图像的URL路径。我还使用位图getBitmapFromURL（）将URL路径转换为BitMapImage。但它显示了NPE（空指针异常）。下面我将粘贴代码Android 如何将URL路径转换为图像并显示在列表视图上,android,Android,根据我尝试搜索商店的位置，搜索结果显示在单元格的列表视图中。我正在从Google获取名称、地址、相关图标和评级，但问题是如何在列表单元格的列表视图上显示图像。我获取了图像的URL路径。我还使用位图getBitmapFromURL（）将URL路径转换为BitMapImage。但它显示了NPE（空指针异常）。下面我将粘贴代码 public class NearByActivity extends Activity implements LocationListener { // private
public class NearByActivity extends Activity implements LocationListener
{
// private ListAdapter adapter;
ListView lvPlaces;
ImageView ivPhone,ivCamera,ivPrinter,ivMore;
String name,vicinity,formatted_phone_number,rating,icon;
double mLatitude=0;
double mLongitude=0;
SharedPreferences spref;
ArrayList<HashMap<String, String>> placesListItems = new ArrayList<HashMap<String,String>>();
// CustomListAdapter customListAdapter;
public ImageLoader imageLoader;
private static final String Name = "name";
private static final String Vicinity = "vicinity";
private static final String Rating="rating";
private static final String Icon="icon";
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.nearby);
lvPlaces=(ListView)findViewById(R.id.lvPlaces);
final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1);
lvPlaces.setAdapter(adapter);
lvPlaces.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
@Override
public void onItemClick(AdapterView<?> MainActivity, final View view,int position, long id)
{
final TextView tvVicinity=(TextView)view.findViewById(R.id.tvVicinity);
final TextView tvRating=(TextView)view.findViewById(R.id.tvRating);
final TextView tvName=(TextView)view.findViewById(R.id.tvName);
final ImageView ivPhone = (ImageView)findViewById(R.id.ivPhone);
final ImageView ivCamera = (ImageView)findViewById(R.id.ivCamera);
final ImageView ivPrinter = (ImageView)findViewById(R.id.ivPrinter);
final ImageView ivMore = (ImageView)findViewById(R.id.ivMore);
ivPhone.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
Toast.makeText(getApplication(),"Do you want the call",Toast.LENGTH_SHORT).show();
}
});
ivCamera.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
Toast.makeText(getApplication(),"Do you want to take pics",Toast.LENGTH_SHORT).show();
}
});
ivPrinter.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
Toast.makeText(getApplication(),"Do you want to print",Toast.LENGTH_SHORT).show();
}
});
ivMore.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
Toast.makeText(getApplication(),"Do you want more",Toast.LENGTH_SHORT).show();
}
});
tvName.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
String getName=tvName.getText().toString();
String getVicinity=tvVicinity.getText().toString();
String getRating=tvRating.getText().toString();
Intent i = new Intent(getApplication(),Information.class);
i.putExtra(Name,getName);
i.putExtra(Vicinity,getVicinity);
i.putExtra(Rating,getRating);
startActivity(i);
}
});
}
});
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
// Creating a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Getting the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
// Getting Current Location From GPS
Location location = locationManager.getLastKnownLocation(provider);
if(location!=null)
{
onLocationChanged(location);
}
locationManager.requestLocationUpdates(provider,20000,0,this);
StringBuilder sb = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
sb.append("location="+mLatitude+","+mLongitude);
sb.append("&radius=1000");
sb.append("&types=beauty_salon");
sb.append("&sensor=true");
sb.append("&key=AIzaSyBgtVo5lfnDQFY8W44TfMevgg2klgj5WeA");
// Creating a new non-ui thread task to download json data
PlacesTask placesTask = new PlacesTask();
// Invokes the "doInBackground()" method of the class PlaceTask
placesTask.execute(sb.toString());
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException
{
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try{
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuffer sb1 = new StringBuffer();
String line = "";
while( ( line = br.readLine()) != null)
{
sb1.append(line);
}
data = sb1.toString();
br.close();
}
catch(Exception e)
{
Log.d("Exception while downloading url", e.toString());
}
finally
{
iStream.close();
urlConnection.disconnect();
}
return data;
}
@Override
public void onLocationChanged(Location location)
{
mLatitude = location.getLatitude();
mLongitude = location.getLongitude();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
}
@Override
public void onProviderEnabled(String provider)
{
}
@Override
public void onProviderDisabled(String provider)
{
}
public Bitmap getBitmapFromURL(String icon ) {
try {
URL url = new URL(icon);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap myBitmap = BitmapFactory.decodeStream(input);
return myBitmap;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
private class PlacesTask extends AsyncTask<String, Integer, String>
{
String data = null;
@Override
protected String doInBackground(String... url)
{
try
{
data = downloadUrl(url[0]);
}
catch(Exception e)
{
Log.d("Background Task",e.toString());
}
return data;
}
@Override
protected void onPostExecute(String result)
{
ParserTask parserTask = new ParserTask();
// Start parsing the Google places in JSON format
// Invokes the "doInBackground()" method of the class ParseTask
parserTask.execute(result);
}
}
private class ParserTask extends AsyncTask<String, Integer, List<HashMap<String,String>>>
{
@Override
protected List<HashMap<String, String>> doInBackground(String... jsonData)
{
JSONObject jObject;
List<HashMap<String, String>> places = null;
PlaceJSONParser placeJsonParser = new PlaceJSONParser();
try
{
jObject = new JSONObject(jsonData[0]);
/** Getting the parsed data as a List construct */
places = placeJsonParser.parse(jObject);
}
catch(Exception e)
{
Log.d("Exception",e.toString());
}
return places;
}
@Override
protected void onPostExecute(List<HashMap<String,String>> list)
{
for(int i=0;i<list.size();i++)
{
HashMap<String, String> hmPlace = list.get(i);
name = hmPlace.get("place_name");
vicinity = hmPlace.get("vicinity");
rating=hmPlace.get("rating");
formatted_phone_number = hmPlace.get("phone_number");
icon = hmPlace.get("icon");
placesListItems.add(hmPlace);
}
Toast.makeText(getApplication(),""+icon,Toast.LENGTH_SHORT).show();
ImageView ivPics = (ImageView)findViewById(R.id.ivPics);
ivPics.setImageBitmap(getBitmapFromURL(icon));
ListAdapter adapter=new SimpleAdapter(NearByActivity.this,placesListItems,
R.layout.myplace,
new String[]{"place_name","vicinity","rating","phone_number"},
new int[]{R.id.tvName,R.id.tvVicinity,R.id.tvRating,R.id.ivPhone});
lvPlaces.setAdapter(adapter);
}
}
URL url = new URL("http://abcd.com/resize?sq=60&uid=2216744464");
Bitmap bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
imageView.setImageBitmap(bmp);
您是否向manifest.xml添加了INTERNET权限
<uses-permission android:name="android.permission.INTERNET" />
是的，我已经添加了权限。当我尝试调试应用程序时，我得到了URL路径，但如何使用简单列表适配器显示图像我不确定，先生。。。。先生，如果您对我的完整程序有任何其他想法，请告诉我。公共位图getBitmapFromURL（字符串图标）{try{URL URL URL=新URL（图标）；在这里，当我添加断点时，我得到了图像URl。@Gautaw Yadav您好，先生，问题只存在于ivpics中。在这种情况下，您能否将此标记为正确答案。您不能使用默认适配器您必须自定义适配器
<uses-permission android:name="android.permission.INTERNET" />
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageBitmap(android.graphics.Bitmap)' on a null object reference