應用程序在滾動列表時崩潰
[英]App is crashing on scrolling of list
問題描述
在我的應用中，我正在顯示地圖和項目列表。 我正在使用Google Place API獲取最近的位置，並在地圖上顯示為具有名稱和附近以及列表的標記。 這是我的代碼
GooglePlacesActivity.java
import android.app.ActionBar;
import android.location.Location;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.CameraPosition;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import java.io.IOException;
import java.util.List;
public class GooglePlacesActivity extends FragmentActivity implements LocationListener, GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener{
GoogleMap mMap;
private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;
private double latitude;
private double longitude;
List<Place> placeList;
ListView listView;
PlaceAdapter mPlaceAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_google_places);
ActionBar actionBar = getActionBar();
actionBar.show();
mGoogleApiClient = new GoogleApiClient.Builder(this).
addApi(LocationServices.API).
addConnectionCallbacks(this).
addOnConnectionFailedListener(this).
build();
actionBar.setCustomView(R.layout.search_actionbar);
final EditText search = (EditText) actionBar.getCustomView().findViewById(R.id.searchField);
listView = (ListView) findViewById(R.id.list_item);
search.setOnEditorActionListener(new TextView.OnEditorActionListener() {
@Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
String value = search.getText().toString();
StringBuilder googlePlacesUrl = new StringBuilder("https://maps.googleapis.com/maps/api/place/search/json?");
googlePlacesUrl.append("location=" + latitude + "," + longitude);
googlePlacesUrl.append("&radius=" + 1000);
googlePlacesUrl.append("&types=" + value);
googlePlacesUrl.append("&key=" + API_KEY);
GooglePlacesTask googlePlacesTask = new GooglePlacesTask();
googlePlacesTask.execute(googlePlacesUrl.toString());
return false;
}
});
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM | ActionBar.DISPLAY_SHOW_HOME);
if (mMap == null){
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.googleMap)).getMap();
mMap.setMyLocationEnabled(true);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_google_places, menu);
return true;
}
@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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
protected void onStart() {
super.onStart();
mGoogleApiClient.connect();
}
@Override
protected void onStop() {
mGoogleApiClient.disconnect();
super.onStop();
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = LocationRequest.create();
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest.setInterval(1000*60);
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
@Override
public void onLocationChanged(Location location) {
latitude = location.getLatitude();
longitude = location.getLongitude();
LatLng latLng = new LatLng(latitude, longitude);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(12));
}
private class GooglePlacesTask extends AsyncTask<String, Void, String>{
String data;
@Override
protected String doInBackground(String... params) {
try{
data = Http.read(params[0]);
Log.d("DATA", data);
}catch (IOException e){
e.printStackTrace();
}
return data;
}
@Override
protected void onPostExecute(String result) {
placeList = ParseJson.parsedata(result);
for (Place place : placeList){
Log.d("Latitude", String.valueOf(place.getLatitude()));
Log.d("Longitude", String.valueOf(place.getLongitude()));
Log.d("Name", place.getName());
Log.d("Vicinity", place.getVicinity());
}
for (int i = 0; i < placeList.size(); i++) {
mMap.addMarker(new MarkerOptions()
.title(placeList.get(i).getName())
.position(
new LatLng(placeList.get(i).getLatitude(), placeList
.get(i).getLongitude()))
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN))
.snippet(placeList.get(i).getVicinity()));
}
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(placeList.get(0).getLatitude(), placeList
.get(0).getLongitude())) // Sets the center of the map to
// Mountain View
.zoom(14) // Sets the zoom
.tilt(30) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
mMap.animateCamera(CameraUpdateFactory
.newCameraPosition(cameraPosition));
mPlaceAdapter = new PlaceAdapter(GooglePlacesActivity.this, placeList);
mPlaceAdapter.notifyDataSetChanged();
listView.setAdapter(mPlaceAdapter);
}
}
}
PlaceAdapter.java
package com.aquib.android.placefinder;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.List;
/**
* Created by dell on 2/19/2015.
*/
public class PlaceAdapter extends ArrayAdapter<Place>{
private final List<Place> list;
private final Context context;
public PlaceAdapter(Context context, List<Place> list){
super(context, R.layout.place_list, list);
this.context = context;
this.list = list;
}
static class ViewHolder{
protected TextView text;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = null;
ViewHolder viewHolder;
if (convertView == null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.place_list, parent, false);
viewHolder = new ViewHolder();
viewHolder.text = (TextView) view.findViewById(R.id.placeName);
view.setTag(viewHolder);
}
else {
viewHolder = (ViewHolder) view.getTag();
}
viewHolder.text.setText(list.get(position).getName());
return view;
}
}
當我滾動列表時，應用程序崩潰並生成NullPointerException。
這個錯誤正在產生
java.lang.NullPointerException
at com.aquib.android.placefinder.PlaceAdapter.getView(PlaceAdapter.java:46)
at android.widget.AbsListView.obtainView(AbsListView.java:2255)
at android.widget.ListView.makeAndAddView(ListView.java:1790)
at android.widget.ListView.fillDown(ListView.java:691)
at android.widget.ListView.fillGap(ListView.java:655)
at android.widget.AbsListView.trackMotionScroll(AbsListView.java:5143)
at android.widget.AbsListView.scrollIfNeeded(AbsListView.java:3243)
at android.widget.AbsListView.onTouchMove(AbsListView.java:3587)
at android.widget.AbsListView.onTouchEvent(AbsListView.java:3431)
at android.view.View.dispatchTouchEvent(View.java:7706)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2210)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1945)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2068)
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1515)
at android.app.Activity.dispatchTouchEvent(Activity.java:2458)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2016)
at android.view.View.dispatchPointerEvent(View.java:7886)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:3947)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3826)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3392)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3442)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3411)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3518)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3419)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3575)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3392)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3442)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3411)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3419)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3392)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5532)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5512)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5483)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:5612)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method)
at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:176)
at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:5585)
at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:5631)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:542)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographe.
1 個解決方案
解決方案1
1 2015-02-19 10:12:21
發生這種情況是因為在滾動列表時會調用getView()方法。 現在您的視圖為空，因此顯示ANR
要克服這種情況，你應該這樣做
@Override
public View getView(int position, View convertView, ViewGroup parent) {
//View view = null;
ViewHolder viewHolder;
if (convertView == null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView= inflater.inflate(R.layout.place_list, parent, false);
viewHolder = new ViewHolder();
viewHolder.text = (TextView) view.findViewById(R.id.placeName);
convertView.setTag(viewHolder);
}
else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.text.setText(list.get(position).getName());
return convertView;
}
滾動列表視圖時應用崩潰
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