如何正確地設置信息從單個列表項膨脹到ArrayList TextView？

Question

對於可能令人困惑的標題，我事先表示歉意，我不確定該如何表達問題，但我會盡力清楚地說明我的問題是什么...

當我嘗試設置TextViews的文本以顯示各個距離時，就會出現我的問題。 我在list_item.xml中使用單個TextView，然后我的Custom ArrayAdapter對其進行膨脹並填充ListView（word_list.xml）。

我嘗試了許多方法，但僅使用一種特定的方法“成功”了-它僅最終用數據填充了第一個列表項，而沒有填充其余的數據。

我的主要問題是mFormattedDistanceString （位於我在此處復制的ListView活動的最底部）。 它是我所有計算出的位置距離信息所駐留的變量。 我似乎無法將其設置為ArrayList中的TextViews。 我覺得答案可能很簡單，但是我似乎無法直截了當-我已經嘗試了許多我研究過的選項，但都沒有用。

ArrayAdapter的自定義數據類型。

public class Word {

private String mName;

private int mImageResourceId = NO_IMAGE_PROVIDED;

private double mDistanceLat;

private double mDistanceLong;

private String mLocationData;

private static final int NO_IMAGE_PROVIDED = -1;

public Word(String name) {
    mName = name;
}

public Word(String name, int imageResourceId) {
    mName = name;
    mImageResourceId = imageResourceId;
}

public Word(String name, int imageResourceId, double distanceLat, double distanceLong,
            String locationData){
    mName = name;
    mImageResourceId = imageResourceId;
    mDistanceLat = distanceLat;
    mDistanceLong = distanceLong;
    mLocationData = locationData;
}

public Word(int imageResourceId) {
    mImageResourceId = imageResourceId;
}

public String getName() {
    return mName;
}

public int getImageResourceId() {
    return mImageResourceId;
}

public double getDistanceLat() {
    return mDistanceLat;
}

public double getDistanceLong() {
    return mDistanceLong;
}

public String getLocationData() {
    return mLocationData;
}

public boolean hasImage() {
    return mImageResourceId != NO_IMAGE_PROVIDED;
}
}

自定義ArrayAdapter。

我已經研究了幾個小時，甚至嘗試了getView方法中的幾種不同方法，但是我無法獲取所有列表項來顯示數據，僅顯示列表中的第一個元素。

public class LocationsAdapter extends ArrayAdapter<Word> {

private LayoutInflater mInflater;
private Context mContext;
private Location mLocation;
private String mFormattedDistanceString;

static class ViewHolder {
    TextView text;
    ImageView image;
    TextView distanceText;
}

public LocationsAdapter(Activity context, List<Word> locations, String formattedDistanceString) {
    super(context, 0, locations);

    mContext = context;
    mInflater = LayoutInflater.from(context);
    mFormattedDistanceString = formattedDistanceString;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder viewHolder;

    Word currentWord = getItem(position);

    if (convertView == null) {

        convertView = mInflater.inflate(R.layout.list_item, parent, false);

        viewHolder = new ViewHolder();

        viewHolder.text = (TextView) convertView.findViewById(R.id.name_text_view);
        viewHolder.image = (ImageView) convertView.findViewById(R.id.icon_image_view);
        viewHolder.distanceText = (TextView) convertView.findViewById(R.id.distance_text_view);

        convertView.setTag(viewHolder);

    } else {

        viewHolder = (ViewHolder) convertView.getTag();
    }

    viewHolder.text.setText(currentWord.getName());
    viewHolder.distanceText.setText(currentWord.getLocationData());


    if (currentWord.hasImage())

    {
        viewHolder.image.setVisibility(View.VISIBLE);
    } else {
        viewHolder.image.setVisibility(View.GONE);
    }

    return convertView;
}
}

我的ListView活動之一。

public class Locations extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener, LocationListener {

    private static final int PERMISSION_REQUEST_ACCESS_FINE_LOCATION = 100;

    private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;

    private static final String LOG_TAG = Locations.class.getName();

    private GoogleApiClient mGoogleApiClient;

    private LocationRequest mLocationRequest;

    private String mFormattedDistanceString;

    public List<Word> locations = new ArrayList<>();

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[],
                                           int[] grantResults) {
        switch (requestCode) {
            case PERMISSION_REQUEST_ACCESS_FINE_LOCATION: {
                mGoogleApiClient.connect();
            }
        }
    }

    private String simplifiedMilesDecimal(double miles) {
        DecimalFormat simplifiedDistance = new DecimalFormat("0.0 Miles Away");
        return simplifiedDistance.format(miles);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.word_list);

        if (ContextCompat.checkSelfPermission(this,
                ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {

            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    ACCESS_FINE_LOCATION)) {

            } else {

                ActivityCompat.requestPermissions(this,
                        new String[]{ACCESS_FINE_LOCATION},
                        PERMISSION_REQUEST_ACCESS_FINE_LOCATION);
            }
        }

        if (mGoogleApiClient == null) {
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .addApi(LocationServices.API)
                    .build();
        }

        mLocationRequest = LocationRequest.create()
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
                .setInterval(10 * 1000)        // 10 seconds, in milliseconds
                .setFastestInterval(1 * 1000); // 1 second, in milliseconds

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);


        locations.add(new Word("Bristol", R.drawable.bristol,
                41.670374, -71.276565, mFormattedDistanceString));
        locations.add(new Word("Warren", R.drawable.warren,
                41.729085, -71.282283, mFormattedDistanceString));
        locations.add(new Word("Newport", R.drawable.newport_breakers,
                41.486677, -71.315144, mFormattedDistanceString));
        locations.add(new Word("Jamestown", R.drawable.jamestown,
                41.496313, -71.368435, mFormattedDistanceString));
        locations.add(new Word("Beavertail", R.drawable.beavertail,
                41.458054, -71.395744, mFormattedDistanceString));
        locations.add(new Word("Providence", R.drawable.providence,
                41.830279, -71.414955, mFormattedDistanceString));
        locations.add(new Word("Roger Williams Park", R.drawable.roger_williams_park,
                41.788673, -71.414179, mFormattedDistanceString));
        locations.add(new Word("Colt State Park", R.drawable.colt_state_park,
                41.677248, -71.298871, mFormattedDistanceString));

        ListView listView = (ListView) findViewById(R.id.list);

        ViewCompat.setNestedScrollingEnabled(listView, true);

        listView.setAdapter(new LocationsAdapter(this, locations, mFormattedDistanceString));

        // Set a click listener to open the default Maps app when the list item is clicked on
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {

                if (position == 0) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.670374, -71.276565?z=15"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 1) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.729085, -71.282283?z=15"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 2) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.486677, -71.315144?z=13"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 3) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.496313, -71.368435?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 4) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.458054, -71.395744?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 5) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.830279, -71.414955?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 6) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.788673, -71.414179?z=16"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 7) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.677248, -71.298871?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                }
            }
        });
    }

    @Override
    protected void onStart() {
        if (ContextCompat.checkSelfPermission(this,
                ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mGoogleApiClient.connect();
        }
        super.onStart();
    }

    @Override
    protected void onResume() {
        if (ContextCompat.checkSelfPermission(this,
                ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mGoogleApiClient.connect();
        }
        super.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (mGoogleApiClient.isConnected()) {
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient,
                    this);
            mGoogleApiClient.disconnect();
        }
    }

    protected void onStop() {
        // If the user has stopped the app, disconnect from the GoogleApiClient.
        mGoogleApiClient.disconnect();
        super.onStop();
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        Log.i(LOG_TAG, "Location services connected.");

        Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

        if (location == null) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
                    mLocationRequest, this);
        } else {
            handleNewLocation(location);
        }
    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.i(LOG_TAG, "Location services suspended. Please reconnect.");
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        if (connectionResult.hasResolution()) {
            try {
                // Start an Activity that tries to resolve the error
                connectionResult.startResolutionForResult(this,
                        CONNECTION_FAILURE_RESOLUTION_REQUEST);
            } catch (IntentSender.SendIntentException e) {
                e.printStackTrace();
            }
        } else {
            Log.i(LOG_TAG, "Location services connection failed with code " +
                    connectionResult.getErrorCode());
        }
    }

    @Override
    public void onLocationChanged(Location location) {
        handleNewLocation(location);
    }

    private void handleNewLocation(Location location) {
        Log.d(LOG_TAG, location.toString());

        LatLng currentUserCoord = new LatLng(location.getLatitude(), location.getLongitude());

        Word locationsListItem = locations.get(0);

        LatLng destinationCoord = new LatLng(locationsListItem.getDistanceLat(),
                locationsListItem.getDistanceLong());

        double distanceInMiles =
                LatLngTool.distance(currentUserCoord, destinationCoord, LengthUnit.MILE);

        String formattedDistance = simplifiedMilesDecimal(distanceInMiles);
        mFormattedDistanceString = toString().valueOf(formattedDistance);
        Log.i(LOG_TAG, mFormattedDistanceString);
    }
}

我嘗試在Locations Activity中使用for循環來遍歷ArrayList中的元素，但是我不確定是否將其設置為錯誤，或者它是否不是解決問題的正確方法。

最好的方法是以某種方式獲取保存在mFormattedDistanceString的位置數據並將其傳遞給LocationsAdapter，以便getView方法可以執行其操作並使用距離信息填充ListView，就像對ImageViews所做的一樣，等等？

讓我知道我是否錯了，以及您認為我應該怎么做！

更新

這是我的代碼塊，其中包含@cark建議的更改，因此我們可以找到解決方案...我覺得這很簡單，但是我無法弄清楚-有太多變量，引用和方法可以跟蹤的... :(

詞類。

public class Word {

    private static final String LOG_TAG = Word.class.getName();

    private String mName;

    private int mImageResourceId = NO_IMAGE_PROVIDED;

    private double mDistanceLat;

    private double mDistanceLong;

    private Location currentLocation;

    private String mFormattedDistanceString;

    private String simplifiedMilesDecimal(double miles) {
        DecimalFormat simplifiedDistance = new DecimalFormat("0.0 Miles Away");
        return simplifiedDistance.format(miles);
    }

    public void updateDistance(Location location){
        if(location.equals(currentLocation)) return;

        LatLng currentUserCoord = new LatLng(location.getLatitude(), location.getLongitude());
        Log.i(LOG_TAG, toString().valueOf(currentUserCoord));

        LatLng destinationCoord = new LatLng(this.getDistanceLat(),
                this.getDistanceLong());

        double distanceInMiles =
                LatLngTool.distance(currentUserCoord, destinationCoord, LengthUnit.MILE);

        String formattedDistance = simplifiedMilesDecimal(distanceInMiles);
        mFormattedDistanceString = toString().valueOf(formattedDistance);

        currentLocation = location;
    }

    private static final int NO_IMAGE_PROVIDED = -1;

    public Word(String name) {
        mName = name;
    }

    public Word(String name, int imageResourceId) {
        mName = name;
        mImageResourceId = imageResourceId;
    }

    public Word(String name, int imageResourceId, double distanceLat, double distanceLong,
                String formattedDistanceString){
        mName = name;
        mImageResourceId = imageResourceId;
        mDistanceLat = distanceLat;
        mDistanceLong = distanceLong;
        mFormattedDistanceString = formattedDistanceString;
    }

    public Word(String name, int imageResourceId, double distanceLat, double distanceLong){
        mName = name;
        mImageResourceId = imageResourceId;
        mDistanceLat = distanceLat;
        mDistanceLong = distanceLong;
    }

    public Word(int imageResourceId) {
        mImageResourceId = imageResourceId;
    }

    public String getName() {
        return mName;
    }

    public int getImageResourceId() {
        return mImageResourceId;
    }

    public double getDistanceLat() {
        return mDistanceLat;
    }

    public double getDistanceLong() {
        return mDistanceLong;
    }

    public String getFormattedDistance() {
        return mFormattedDistanceString;
    }

    public boolean hasImage() {
        return mImageResourceId != NO_IMAGE_PROVIDED;
    }
}

LocationsAdapter類。

public class LocationsAdapter extends ArrayAdapter<Word> {

    private LayoutInflater mInflater;
    private Context mContext;
    private Location mLocation;

    static class ViewHolder {
        TextView text;
        ImageView image;
        TextView distanceText;
    }

    public LocationsAdapter(Activity context, List<Word> locations, Location location) {
        super(context, 0, locations);

        mLocation = location;
        mContext = context;
        mInflater = LayoutInflater.from(context);
    }

    public void setCurrentLocation(Location lastLocation)
    {
        mLocation = lastLocation;
    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolder viewHolder;

        Word currentWord = getItem(position);

        if (convertView == null) {

            convertView = mInflater.inflate(R.layout.list_item, parent, false);

            viewHolder = new ViewHolder();

            viewHolder.text = (TextView) convertView.findViewById(R.id.name_text_view);
            viewHolder.image = (ImageView) convertView.findViewById(R.id.icon_image_view);
            viewHolder.distanceText = (TextView) convertView.findViewById(R.id.distance_text_view);

            convertView.setTag(viewHolder);

        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        viewHolder.text.setText(currentWord.getName());

        currentWord.updateDistance(mLocation);
        viewHolder.distanceText.setText(currentWord.getFormattedDistance());

        if (currentWord.hasImage())

        {

            viewHolder.image.setImageResource(currentWord.getImageResourceId());

            viewHolder.image.setVisibility(View.VISIBLE);
        } else {
            // Otherwise hide the ImageView (set visibility to GONE)
            viewHolder.image.setVisibility(View.GONE);
        }

        return convertView;
    }
}

位置活動。

public class Locations extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener, LocationListener {

    private static final int PERMISSION_REQUEST_ACCESS_FINE_LOCATION = 100;

    private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;

    private static final String LOG_TAG = Locations.class.getName();

    private GoogleApiClient mGoogleApiClient;

    private LocationRequest mLocationRequest;

    private String mFormattedDistanceString;

    Location mLocation = new Location(LocationManager.NETWORK_PROVIDER);

    private ListView mListView;

    public List<Word> locations = new ArrayList<>();

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[],
                                           int[] grantResults) {
        switch (requestCode) {
            case PERMISSION_REQUEST_ACCESS_FINE_LOCATION: {
                mGoogleApiClient.connect();
            }
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.word_list);

        mListView = (ListView) findViewById(R.id.list);

        if (ContextCompat.checkSelfPermission(this,
                ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {

            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    ACCESS_FINE_LOCATION)) {

            } else {

                ActivityCompat.requestPermissions(this,
                        new String[]{ACCESS_FINE_LOCATION},
                        PERMISSION_REQUEST_ACCESS_FINE_LOCATION);

            }
        }

        if (mGoogleApiClient == null) {
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .addApi(LocationServices.API)
                    .build();
        }

        mLocationRequest = LocationRequest.create()
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
                .setInterval(10 * 1000)        // 10 seconds, in milliseconds
                .setFastestInterval(1 * 1000); // 1 second, in milliseconds

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

        setSupportActionBar(toolbar);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        mFormattedDistanceString = new String();

        locations.add(new Word("Bristol", R.drawable.bristol,
                41.670374, -71.276565, mFormattedDistanceString));
        locations.add(new Word("Warren", R.drawable.warren,
                41.729085, -71.282283, mFormattedDistanceString));
        locations.add(new Word("Newport", R.drawable.newport_breakers,
                41.486677, -71.315144, mFormattedDistanceString));
        locations.add(new Word("Jamestown", R.drawable.jamestown,
                41.496313, -71.368435, mFormattedDistanceString));
        locations.add(new Word("Beavertail", R.drawable.beavertail,
                41.458054, -71.395744, mFormattedDistanceString));
        locations.add(new Word("Providence", R.drawable.providence,
                41.830279, -71.414955, mFormattedDistanceString));
        locations.add(new Word("Roger Williams Park", R.drawable.roger_williams_park,
                41.788673, -71.414179, mFormattedDistanceString));
        locations.add(new Word("Colt State Park", R.drawable.colt_state_park,
                41.677248, -71.298871, mFormattedDistanceString));

        ViewCompat.setNestedScrollingEnabled(mListView, true);

        mListView.setAdapter(new LocationsAdapter(this, locations, mLocation));

        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {

                if (position == 0) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.670374, -71.276565?z=15"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 1) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.729085, -71.282283?z=15"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 2) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.486677, -71.315144?z=13"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 3) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.496313, -71.368435?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 4) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.458054, -71.395744?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 5) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.830279, -71.414955?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 6) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.788673, -71.414179?z=16"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                } else if (position == 7) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse("geo:41.677248, -71.298871?z=14"));
                    if (intent.resolveActivity(getPackageManager()) != null) {
                        startActivity(intent);
                    }
                }
            }
        });
    }

    @Override
    protected void onStart() {
        // If the app already has the permission to access the user's location at high accuracy
        // (fine location), then connect to the GoogleApiClient.
        if (ContextCompat.checkSelfPermission(this,
                ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mGoogleApiClient.connect();
        }
        super.onStart();
    }

    @Override
    protected void onResume() {

        if (ContextCompat.checkSelfPermission(this,
                ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mGoogleApiClient.connect();
        }
        super.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();

        if (mGoogleApiClient.isConnected()) {
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient,
                    this);
            mGoogleApiClient.disconnect();
        }
    }

    protected void onStop() {
        // If the user has stopped the app, disconnect from the GoogleApiClient.
        mGoogleApiClient.disconnect();
        super.onStop();
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        Log.i(LOG_TAG, "Location services connected.");

        mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

        if (mLocation == null) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
                    mLocationRequest, this);
        } else {
            handleNewLocation(mLocation);
        }
    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.i(LOG_TAG, "Location services suspended. Please reconnect.");
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        if (connectionResult.hasResolution()) {
            try {
                connectionResult.startResolutionForResult(this,
                        CONNECTION_FAILURE_RESOLUTION_REQUEST);
            } catch (IntentSender.SendIntentException e) {
                e.printStackTrace();
            }
        } else {
            Log.i(LOG_TAG, "Location services connection failed with code " +
                    connectionResult.getErrorCode());
        }
    }

    @Override
    public void onLocationChanged(Location location) {

        LocationsAdapter adapter = (LocationsAdapter) mListView.getAdapter();
        adapter.setCurrentLocation(location);
        adapter.notifyDataSetChanged();
    }

    private void handleNewLocation(Location location) {
        Log.d(LOG_TAG, location.toString());

    }
}

Answer 1

嘗試這個：

• 調用onLocationChanged時，將位置傳遞給LocationsAdapter（創建方法setCurrentLocation ）。

• 調用(LocationsAdapter)(listView.getAdapter()).notifyDataSetChanged(); （listView必須成為一個類字段）

• 在適配器的getView ，計算距離並將文本設置為textView。

為了優化距離計算，您可以將值存儲在模型中，但請記住也要存儲Location對象。 這樣，您可以在以后的調用中檢查Location對象是否已更改。 如果“位置”對象發生更改，則需要重新計算距離，否則可以顯示上一次計算的距離。

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更新

刪除private String mFormattedDistanceString; 來自LocationsAdapter 。 您不需要它，也可以將其從構造函數中刪除。

在LocationsAdapter您具有mLocation ，但從未分配它。 將此方法添加到LocationsAdapter以便在您的活動發生更改時分配mLocation。
public void setCurrentLocation(Location lastLocation){ mLocation = lastLocation}

使listView成為Locations活動的一個字段，並以這種方式更改onLocationChanged ：

public void onLocationChanged(Location location) {
    LocationsAdapter adapter = (LocationsAdapter)listView.getAdapter();
    adapter.setCurrentLocation(location);
    adapter.notifyDataSetChanged();
}

在您的Word類中創建此方法：

Location currentLocation;
public void updateDistance(Location location){
    if(location.equals(currentLocation)) return;
    //calculate the distance and create the distance string, and set it 
    //as a class field (you can call it mFormattedDistanceString)
    currentLocation = location;
}

在適配器的getView中，調用updateDistance ，然后使用Word mFormattedDistanceString設置TextView文本。