Android从另一个类获取数据

Question

我之前在另一篇文章中尝试过解决这个问题，但没有成功。这就是我想要完成的事情：当用户单击 gpsbtn 时，它将从 gps.printLocation 方法中获取长/纬度。我想自动填充edittext，但我想我可以通过快速的谷歌搜索弄清楚如何做到这一点。因此，如果我可以将坐标存储到一个变量中，这将是我想要的，但我的大脑无法工作。完整代码：

public class Location extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Full Screen
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

        setContentView(R.layout.location);

        // Go button
        Button gobtn = (Button) findViewById(R.id.gobtn);
        final EditText Zipcodeinput = (EditText) findViewById(R.id.Zipcode);
        gobtn.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                // Edit text validation field
                Pattern pattern = Pattern.compile("[0-9][0-9][0-9][0-9][0-9]"); // string needs 5 digits
                // argument to matcher is string to validate
                Matcher matcher = pattern.matcher(Zipcodeinput.getText()
                        .toString());
                if (!matcher.matches()) // on Success
                {
                    // invalid
                    // pop up ERROR message
                    Toast.makeText(getBaseContext(), " Invalid Input ",
                            Toast.LENGTH_LONG).show();

                } else {
                    // validation successful
                    // Change to Listings Page
                    Intent filterIntent = new Intent(view.getContext(),
                            Listings.class);
                    startActivityForResult(filterIntent, 0);
                }
            }
        });

        // button to get to list view
        Button gpsbtn = (Button) findViewById(R.id.gps); // temp use of gps
                                                            // button
        gpsbtn.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {

                // Toast.makeText(getApplicationContext(), "Please wait...",
                // Toast.LENGTH_LONG).show();
                Intent gpsIntent = new Intent(view.getContext(), gps.class);
                startActivityForResult(gpsIntent, 0);

            }

        });

    }
}

我想从中提取信息的类：

public class gps extends Activity implements LocationListener {

    //private static final String[] S = { "Out of Service",
            //"Temporarily Unavailable", "Available" };

    private TextView output2;
    private LocationManager locationManager;
    private String bestProvider;
    double latitude,longitude;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.gps);
        try {   
        // Get the output UI
        //output = (TextView) findViewById(R.id.output);
        output2 = (TextView) findViewById(R.id.output2);

        // Get the location manager
        locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        // List all providers:
        List<String> providers = locationManager.getAllProviders();
        for (String provider : providers) {
            printProvider(provider);
        }

        Criteria criteria = new Criteria();
        bestProvider = locationManager.getBestProvider(criteria, false);
        //output.append("\n\nBEST Provider:\n");
        printProvider(bestProvider);

        //output.append("\n\nLocations (starting with last known):");
        Location location = locationManager.getLastKnownLocation(bestProvider);
        printLocation(location);
        }
        catch (Exception e)
        {
            Toast.makeText(getBaseContext(), "Error Getting GPS" , Toast.LENGTH_LONG);
        }

    }

    /** Register for the updates when Activity is in foreground */
    @Override
    protected void onResume() {
        super.onResume();

    }

    /** Stop the updates when Activity is paused */
    @Override
    protected void onPause() {
        super.onPause();
        locationManager.removeUpdates(this);
    }

    public void onLocationChanged(Location location) {
        printLocation(location);
    }

    public void onProviderDisabled(String provider) {
        // let okProvider be bestProvider
        // re-register for updates
    }

    public void onProviderEnabled(String provider) {
        // is provider better than bestProvider?
        // is yes, bestProvider = provider
    }

    public void onStatusChanged(String provider, int status, Bundle extras) {
        //output.append("\n\nProvider Status Changed: " + provider + ", Status="
            //  + S[status] + ", Extras=" + extras);
    }

    private void printProvider(String provider) {
        //LocationProvider info = locationManager.getProvider(provider);
        //output.append(info.toString() + "\n\n");
    }





    //PRINTS the long and lat. Take out round before release

    private void printLocation(Location location) {
        output2.append("Lat:"+location.getLatitude()+"\nLong: "+location.getLongitude());
        latitude = Math.round(location.getLatitude());
        longitude = Math.round(location.getLongitude());

         Toast.makeText(getBaseContext(), "Lat: " + latitude + "| Long: " + longitude, Toast.LENGTH_LONG).show();



    }

我很迷茫！谢谢！

Answer 1

您可以将坐标保存到共享首选项中，该共享首选项可用于应用程序中的所有类。 Shared Prefs

或者您可以创建一个从 Application 类扩展而来的“全局”类，并编写您自己的 setter 和 getter 方法来访问存储在这个 Global 类中的数据。

public class MyApp extends Application {

      public String string1;

      public String getState(){
        return string1;
      }
      public void setState(input){
        this.string1 = input;
      }
}

要从应用程序中的任何其他类使用任何类获取存储的数据：

MyApp appState = ((MyApp)getApplicationContext());
String x = appState.getState();
appState.setState(x);

Answer 2

未经测试，但我会考虑使用共享首选项：

public static final String USER_LATITUDE = "user.lat";
public static final String USER_LONGTITUDE = "user.long";
public static final String USER_SHARED_PREFS = "user.prefs";

private void printLocation(Location location) {

    SharedPreferences prefs = getSharedPreferences(USER_SHARED_PREFS, MODE_PRIVATE);
    Editor editor = prefs.edit();
    long latitude = Math.round(location.getLatitude());
    long longitude = Math.round(location.getLongitude());

    editor.putLong(USER_LATITUDE, latitude).commit();
    editor.putLong(USER_LONGTITUDE, longitude).commit();

}

private void doSTuff(){
    SharedPreferences prefs = getSharedPreferences(USER_SHARED_PREFS, MODE_PRIVATE);
    prefs.getLong(USER_LATITUDE, 0);
    prefs.getLong(USER_LONGTITUDE, 0);
}

共享首选项实例是原子的，因此只要您在编辑器上进行提交，您的阅读器类中的 sharedPreferences 实例就可以读取更改。

可能的问题，位置的默认值，sharedPreferences 中没有可用的位置对象，只有 long 和 lat，这意味着您无法得出位置读取的准确性或时间。

Answer 3

在MainActivity下写公共类MainActivity extends AppCompatActivity {:

    public class MainActivity extends AppCompatActivity {
    public static String test = "OK it's working";
    ...

在另一个活动中写：

    public class NameOfYourClass extends AppCompatActivity {
    String testInAnotherClass = MainActivity.test;

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

    Toast.makeText(getApplicationContext(),testInAnotherClass , Toast.LENGTH_SHORT).show();
...