如何解决GPS 位置不会显示在手机上
我正在尝试从 GPS 获取位置并将其显示在屏幕上,到目前为止我有这个代码:
public class MainActivity extends AppCompatActivity implements LocationListener {
EditText el;
TextView output;
LocationManager lm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
el = (EditText) findViewById(R.id.editText);
output = (TextView) findViewById(R.id.textView2);
output.setMovementMethod(new ScrollingMovementMethod());
output.setText("");
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
output.append("Start");
if (ActivityCompat.checkSelfPermission(MainActivity.this,Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(MainActivity.this,Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
//ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.ACCESS_COARSE_LOCATION,Manifest.permission.ACCESS_FINE_LOCATION},1);
output.append("Initially Failed to Grand Permission\n");
return;
}
output.append("\nOutside Permission controle");
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,10,1,this);
output.append("\nYoo");
}
public void send(View v) {
MessageSender messageSender = new MessageSender();
messageSender.execute(el.getText().toString());
output.append("Hello\n");
}
@Override
public void onLocationChanged(@NonNull Location location) {
output.append("Inside location function");
output.append(String.valueOf(location.getLongitude()));
}
}
我还在 android manifest 中添加了精细位置和粗略位置的权限。我错过了什么?
我使用的是三星 Galaxy S10
注意 当我在 android studio 上使用模拟器时,它会显示位置,但是当我使用 USB 调试器并在我的 android 设备上运行它时,它不显示位置
还有 即使我在模拟器上运行它,当我移动我的笔记本电脑时,位置也不会更新,为什么?
解决方法
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,10,1,this);
ACCESS_FINE_LOCATION
和 ACCESS_COARSE_LOCATION
,会导致错误,因此您必须询问这些权限。你可以这样做:
if (ActivityCompat.checkSelfPermission(MainActivity.this,Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED ||
ActivityCompat.checkSelfPermission(MainActivity.this,Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.ACCESS_COARSE_LOCATION,Manifest.permission.ACCESS_FINE_LOCATION},1);
} else {
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER,this);
}
请注意,&&
已更改为 ||
。基本上,此代码会询问是否未授予权限。如果已授予权限,请调用 locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,this);
如果未授予权限怎么办?您需要等到权限被授予后才能调用 requestLocationUpdates
。授予权限后调用此方法。
@Override
public void onRequestPermissionsResult(int requestCode,String permissions[],int[] grantResults) {
switch (requestCode) {
case 1: {
// If request is cancelled,the result arrays are empty.
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
if (ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,this);
return;
}
}
}
将此方法添加到活动中。我用物理设备测试了这段代码,它似乎可以正常工作。
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