Ví dụ này trình bày cách truy cập Android GPS, Trình quản lý vị trí
Bước 1 - Tạo một dự án mới trong Android Studio, đi tới Tệp ⇒ Dự án Mới và điền tất cả các chi tiết cần thiết để tạo một dự án mới.
Bước 2 - Thêm mã sau vào res / layout / activity_main.xml.
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android" xmlns:tools="https://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center_horizontal" android:orientation="vertical" tools:context=".MainActivity"> <Button android:id="@+id/btn_start_location_updates" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="40dp" android:onClick="startLocationButtonClick" android:text="@string/start_updates" /> <Button android:id="@+id/btn_stop_location_updates" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:enabled="false" android:onClick="stopLocationButtonClick" android:text="@string/stop_updates" /> <Button android:id="@+id/btn_get_last_location" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:onClick="showLastKnownLocation" android:text="@string/get_last_location" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="50dp" android:gravity="center_horizontal" android:text="Location updates will be received only when app is foreground" /> <TextView android:id="@+id/location_result" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="20dp" android:textColor="#333" android:textSize="18sp" /> <TextView android:id="@+id/updated_on" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="30dp" android:textSize="12sp" /> </LinearLayout>
Bước 3 - Thêm mã sau vào src / MainActivity.java
package app.com.sample;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.content.IntentSender;
import android.content.pm.PackageManager;
import android.location.Location;
import android.net.Uri;
import android.os.Bundle;
import android.os.Looper;
import android.provider.Settings;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.api.ApiException;
import com.google.android.gms.common.api.ResolvableApiException;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.location.LocationSettingsRequest;
import com.google.android.gms.location.LocationSettingsResponse;
import com.google.android.gms.location.LocationSettingsStatusCodes;
import com.google.android.gms.location.SettingsClient;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.karumi.dexter.Dexter;
import com.karumi.dexter.PermissionToken;
import com.karumi.dexter.listener.PermissionDeniedResponse;
import com.karumi.dexter.listener.PermissionGrantedResponse;
import com.karumi.dexter.listener.PermissionRequest;
import com.karumi.dexter.listener.single.PermissionListener;
import java.text.DateFormat;
import java.util.Date;
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
TextView txtLocationResult;
TextView txtUpdatedOn;
Button btnStartUpdates;
Button btnStopUpdates;
// location last updated time
private String mLastUpdateTime;
// location updates interval - 10sec
private static final long UPDATE_INTERVAL_IN_MILLISECONDS = 10000;
// fastest updates interval - 5 sec
// location updates will be received if another app is requesting the locations
// than your app can handle
private static final long FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS = 5000;
private static final int REQUEST_CHECK_SETTINGS = 100;
// bunch of location related apis
private FusedLocationProviderClient mFusedLocationClient;
private SettingsClient mSettingsClient;
private LocationRequest mLocationRequest;
private LocationSettingsRequest mLocationSettingsRequest;
private LocationCallback mLocationCallback;
private Location mCurrentLocation;
// boolean flag to toggle the ui
private Boolean mRequestingLocationUpdates;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// initialize the necessary libraries
init();
// restore the values from saved instance state
restoreValuesFromBundle(savedInstanceState);
}
private void init() {
txtLocationResult = findViewById(R.id.location_result);
txtUpdatedOn = findViewById(R.id.updated_on);
btnStartUpdates = findViewById(R.id.btn_start_location_updates);
btnStopUpdates = findViewById(R.id.btn_stop_location_updates);
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
mSettingsClient = LocationServices.getSettingsClient(this);
mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
super.onLocationResult(locationResult);
// location is received
mCurrentLocation = locationResult.getLastLocation();
mLastUpdateTime = DateFormat.getTimeInstance().format(new Date());
updateLocationUI();
}
};
mRequestingLocationUpdates = false;
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();
builder.addLocationRequest(mLocationRequest);
mLocationSettingsRequest = builder.build();
}
/**
* Restoring values from saved instance state
*/
private void restoreValuesFromBundle(Bundle savedInstanceState) {
if (savedInstanceState != null) {
if (savedInstanceState.containsKey("is_requesting_updates")) {
mRequestingLocationUpdates = savedInstanceState.getBoolean("is_requesting_updates");
}
if (savedInstanceState.containsKey("last_known_location")) {
mCurrentLocation = savedInstanceState.getParcelable("last_known_location");
}
if (savedInstanceState.containsKey("last_updated_on")) {
mLastUpdateTime = savedInstanceState.getString("last_updated_on");
}
}
updateLocationUI();
}
/**
* Update the UI displaying the location data
* and toggling the buttons
*/
private void updateLocationUI() {
if (mCurrentLocation != null) {
txtLocationResult.setText(
"Lat: " + mCurrentLocation.getLatitude() + ", " +
"Lng: " + mCurrentLocation.getLongitude()
);
// giving a blink animation on TextView
txtLocationResult.setAlpha(0);
txtLocationResult.animate().alpha(1).setDuration(300);
// location last updated time
txtUpdatedOn.setText("Last updated on: " + mLastUpdateTime);
}
toggleButtons();
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putBoolean("is_requesting_updates", mRequestingLocationUpdates);
outState.putParcelable("last_known_location", mCurrentLocation);
outState.putString("last_updated_on", mLastUpdateTime);
}
private void toggleButtons() {
if (mRequestingLocationUpdates) {
btnStartUpdates.setEnabled(false);
btnStopUpdates.setEnabled(true);
}
else {
btnStartUpdates.setEnabled(true);
btnStopUpdates.setEnabled(false);
}
}
/**
* Starting location updates
* Check whether location settings are satisfied and then
* location updates will be requested
*/
private void startLocationUpdates() {
mSettingsClient
.checkLocationSettings(mLocationSettingsRequest)
.addOnSuccessListener(this, new OnSuccessListener() {
@SuppressLint("MissingPermission")
@Override
public void onSuccess(LocationSettingsResponse locationSettingsResponse) {
Log.i(TAG, "All location settings are satisfied.");
Toast.makeText(getApplicationContext(), "Started location updates!",
Toast.LENGTH_SHORT).show();
//noinspection MissingPermission
mFusedLocationClient.requestLocationUpdates(mLocationRequest,
mLocationCallback, Looper.myLooper());
updateLocationUI();
}
})
.addOnFailureListener(this, new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
int statusCode = ((ApiException) e).getStatusCode();
switch (statusCode) {
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
Log.i(TAG, "Location settings are not satisfied. Attempting to upgrade " + "location settings ");
try {
// Show the dialog by calling startResolutionForResult(), and check the
// result in onActivityResult().
ResolvableApiException rae = (ResolvableApiException) e;
rae.startResolutionForResult(MainActivity.this, REQUEST_CHECK_SETTINGS);
}
catch (IntentSender.SendIntentException sie) {
Log.i(TAG, "PendingIntent unable to execute request.");
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
String errorMessage = "Location settings are inadequate, and cannot be " + "fixed here. Fix in Settings.";
Log.e(TAG, errorMessage);
Toast.makeText(MainActivity.this, errorMessage, Toast.LENGTH_LONG).show();
}
updateLocationUI();
}
});
}
public void startLocationButtonClick(View view) {
// Requesting ACCESS_FINE_LOCATION using Dexter library
Dexter.withActivity(this)
.withPermission(Manifest.permission.ACCESS_FINE_LOCATION)
.withListener(new PermissionListener() {
@Override
public void onPermissionGranted(PermissionGrantedResponse response) {
mRequestingLocationUpdates = true;
startLocationUpdates();
}
@Override
public void onPermissionDenied(PermissionDeniedResponse response) {
if (response.isPermanentlyDenied()) {
// open device settings when the permission is
// denied permanently
openSettings();
}
}
@Override
public void onPermissionRationaleShouldBeShown(PermissionRequest permission,
PermissionToken token) {
token.continuePermissionRequest();
}
}).check();
}
public void stopLocationButtonClick(View view) {
mRequestingLocationUpdates = false;
stopLocationUpdates();
}
public void stopLocationUpdates() {
// Removing location updates
mFusedLocationClient
.removeLocationUpdates(mLocationCallback)
.addOnCompleteListener(this, new OnCompleteListener() {
@Override
public void onComplete(@NonNull Task task) {
Toast.makeText(getApplicationContext(), "Location updates stopped!",
Toast.LENGTH_SHORT).show();
toggleButtons();
}
});
}
public void showLastKnownLocation(View view) {
if (mCurrentLocation != null) {
Toast.makeText(getApplicationContext(), "Lat: " + mCurrentLocation.getLatitude() + ", Lng: " + mCurrentLocation.getLongitude(), Toast.LENGTH_LONG).show();
}
else {
Toast.makeText(getApplicationContext(), "Last known location is not available!",
Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// Check for the integer request code originally supplied to startResolutionForResult().
if (requestCode == REQUEST_CHECK_SETTINGS) {
switch (resultCode) {
case Activity.RESULT_OK:
Log.e(TAG, "User agreed to make required location settings changes.");
// Nothing to do. startLocationupdates() gets called in onResume again.
break;
case Activity.RESULT_CANCELED:
Log.e(TAG, "User chose not to make required location settings changes.");
mRequestingLocationUpdates = false;
break;
}
}
}
private void openSettings() {
Intent intent = new Intent();
intent.setAction(
Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
Uri uri = Uri.fromParts("package",
BuildConfig.APPLICATION_ID, null);
intent.setData(uri);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
@Override
public void onResume() {
super.onResume();
// Resuming location updates depending on button state and
// allowed permissions
if (mRequestingLocationUpdates && checkPermissions()) {
startLocationUpdates();
}
updateLocationUI();
}
private boolean checkPermissions() {
int permissionState = ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION);
return permissionState == PackageManager.PERMISSION_GRANTED;
}
@Override
protected void onPause() {
super.onPause();
if (mRequestingLocationUpdates) {
// pausing location updates
stopLocationUpdates();
}
}
} Bước 4 - Thêm mã sau vào androidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="https://schemas.android.com/apk/res/android" package="app.com.sample"> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
Hãy thử chạy ứng dụng của bạn. Tôi giả sử bạn đã kết nối thiết bị Di động Android thực tế với máy tính của mình. Để chạy ứng dụng từ studio android, hãy mở một trong các tệp hoạt động của dự án của bạn và nhấp vào biểu tượng Run từ thanh công cụ. Chọn thiết bị di động của bạn làm tùy chọn, sau đó kiểm tra thiết bị di động sẽ hiển thị màn hình mặc định của bạn -
