Android Gps座標

Question

我是Android應用程序開發的新手，我試圖獲取GPS坐標，但無法弄清楚我的代碼有問題的地方。 我正在使用android studio 1.4版本，並且該項目基於ICE CREAM Sandwich 4.0.3構建。使用一些文章，我嘗試獲取坐標，但是我始終面臨獲取坐標的問題。

這是我的代碼

這就是我在manifest.xml文件中定義權限設置的方式

<uses-permission android:name="android.permission.INTERNET"></uses-permission>

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"></uses-permission>

這些是我在content_main.xml文件中擁有的控件

<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="40dip"
android:orientation="horizontal" >

<TextView
android:id="@+id/TextView01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dip"
android:layout_marginRight="5dip"
android:text="Latitude: "
android:textSize="20dip" >
</TextView>

<TextView
android:id="@+id/TextView02"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="unknown"
android:textSize="20dip" >
</TextView>
</LinearLayout>

<LinearLayout
android:id="@+id/linearLayout2"
android:layout_width="match_parent"
android:layout_height="wrap_content" >

<TextView
android:id="@+id/TextView03"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dip"
android:layout_marginRight="5dip"
android:text="Longitute: "
android:textSize="20dip" >
</TextView>

<TextView
android:id="@+id/TextView04"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="unknown"
android:textSize="20dip" >
</TextView>
</LinearLayout>

最后是我的MainActivity.java文件

package com.example.dell.soslocation;

import android.Manifest;
import android.annotation.TargetApi;
import android.app.Notification;
import android.content.pm.PackageManager;
import android.net.wifi.p2p.WifiP2pManager;
import android.os.Build;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements     
LocationListener {

private TextView latituteField;
private TextView longitudeField;
private LocationManager locationManager;
private String provider;

@TargetApi(Build.VERSION_CODES.M)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});

latituteField = (TextView) findViewById(R.id.TextView02);
longitudeField = (TextView) findViewById(R.id.TextView04);

// Get the location manager
locationManager = (LocationManager) 
getSystemService(Context.LOCATION_SERVICE);
// Define the criteria how to select the locatioin provider -> use
// default
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != 
PackageManager.PERMISSION_GRANTED && 
checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != 
PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// public void requestPermissions(@NonNull String[] permissions, int 
requestCode)
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] 
permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the 
documentation
// for Activity#requestPermissions for more details.
return;
}
Location location = locationManager.getLastKnownLocation(provider);

// Initialize the location fields
if (location != null) {
System.out.println("Provider " + provider + " has been selected.");
onLocationChanged(location);
} else {
latituteField.setText("Location not available");
longitudeField.setText("Location not available");
}
}

/* Request updates at startup */
@TargetApi(Build.VERSION_CODES.M)
@Override
protected void onResume() {
super.onResume();
if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != 
PackageManager.PERMISSION_GRANTED && 
checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != 
PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// public void requestPermissions(@NonNull String[] permissions, int 
requestCode)
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] 
permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the 
documentation
// for Activity#requestPermissions for more details.
return;
}
locationManager.requestLocationUpdates(provider, 400, 1, this);
}

/* Remove the locationlistener updates when Activity is paused */
@TargetApi(Build.VERSION_CODES.M)
@Override
protected void onPause() {
super.onPause();
if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != 
PackageManager.PERMISSION_GRANTED && 
checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != 
PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// public void requestPermissions(@NonNull String[] permissions, int 
requestCode)
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] 
permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the 
documentation
// for Activity#requestPermissions for more details.
return;
}
locationManager.removeUpdates(this);
}

@Override
public void onLocationChanged(Location location) {
int lat = (int) (location.getLatitude());
int lng = (int) (location.getLongitude());
latituteField.setText(String.valueOf(lat));
longitudeField.setText(String.valueOf(lng));
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}

@Override
public void onProviderEnabled(String provider) {
Toast.makeText(this, "Enabled new provider " + provider,
Toast.LENGTH_SHORT).show();

}

@Override
public void onProviderDisabled(String provider) {
Toast.makeText(this, "Disabled provider " + provider,
Toast.LENGTH_SHORT).show();
}

@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_main, 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);
}
}

當我在android模擬器Nexus 4 Api 23中運行應用程序但沒有顯示任何坐標時，沒有錯誤，因為提供程序始終為null。 當我在設備上安裝設備時，它無法啟動，並顯示錯誤消息“不幸的是，該應用程序已停止”

有人可以告訴我代碼中有什么問題嗎？

謝謝，

Answer 1

Here is an easy way to get the coordinates, 
//activity-main.xml  

     <TextView
        android:id="@+id/tv_longitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tv_location"
        android:layout_centerHorizontal="true" />


     <TextView
        android:id="@+id/tv_longitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tv_location"
        android:layout_centerHorizontal="true" />
 <TextView
        android:id="@+id/tv_latitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tv_longitude"
        android:layout_centerHorizontal="true"/>

  //MainActivity.java 

    import android.app.Activity;
    import android.content.Context;
    import android.location.Criteria;
    import android.location.Location;
    import android.location.LocationListener;
    import android.location.LocationManager;
    import android.os.Bundle;
    import android.view.Menu;
    import android.widget.TextView;
    import android.widget.Toast;

    public class MainActivity extends Activity implements LocationListener{

    LocationManager locationManager ;
    String provider;

    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Getting LocationManager object
    locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);

    // Creating an empty criteria object
    Criteria criteria = new Criteria();

    // Getting the name of the provider that meets the criteria
    provider = locationManager.getBestProvider(criteria, false);

    if(provider!=null && !provider.equals("")){

    // Get the location from the given provider
    Location location = locationManager.getLastKnownLocation(provider);

    locationManager.requestLocationUpdates(provider, 20000, 1, this);

    if(location!=null)
    onLocationChanged(location);
    else
    Toast.makeText(getBaseContext(), "Location can't be retrieved", Toast.LENGTH_SHORT).show();

    }else{
    Toast.makeText(getBaseContext(), "No Provider Found", Toast.LENGTH_SHORT).show();
    }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
    }

    @Override
    public void onLocationChanged(Location location) {
    // Getting reference to TextView tv_longitude
    TextView tvLongitude = (TextView)findViewById(R.id.tv_longitude);

    // Getting reference to TextView tv_latitude
    TextView tvLatitude = (TextView)findViewById(R.id.tv_latitude);

    // Setting Current Longitude
    tvLongitude.setText("Longitude:" + location.getLongitude());

    // Setting Current Latitude
    tvLatitude.setText("Latitude:" + location.getLatitude() );
    }

    @Override
    public void onProviderDisabled(String provider) {
    // TODO Auto-generated method stub
    }

    @Override
    public void onProviderEnabled(String provider) {
    // TODO Auto-generated method stub
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
    // TODO Auto-generated method stub
    }
    }