android studio定位gps

1.AndroidManifest.xml檔案中添權重限

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

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

2.布局檔案activity_main.xml

<?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:textStyle="bold"
        android:textSize="20sp"
        android:padding="5dp"
        android:id="@+id/tv_show"/>


</androidx.constraintlayout.widget.ConstraintLayout>
           

3.後端代碼

package com.example.mygps;

import android.Manifest;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;


public class MainActivity extends AppCompatActivity {

    private LocationManager lm;
    private TextView tv_show;

    @SuppressLint("MissingPermission")
    @RequiresApi(api = Build.VERSION_CODES.M)
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv_show = findViewById(R.id.tv_show);
        lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        if (!isGpsAble(lm)) {
            Toast.makeText(MainActivity.this, "請打開GPS", Toast.LENGTH_SHORT).show();
            openGPS2();
        }
        if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {//未開啟定位權限
            //開啟定位權限,200是辨別碼
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 200);
        } else {
            startLocation();
            Toast.makeText(MainActivity.this, "已開啟定位權限", Toast.LENGTH_LONG).show();
        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode){
            case 200://剛才的識别碼
                if(grantResults[0] == PackageManager.PERMISSION_GRANTED){//使用者同意權限,執行我們的操作
                    startLocation();//開始定位
                }else{//使用者拒絕之後,當然我們也可以彈出一個視窗,直接跳轉到系統設定頁面
                    Toast.makeText(MainActivity.this,"未開啟定位權限,請手動到設定去開啟權限",Toast.LENGTH_LONG).show();
                }
                break;
            default:break;
        }
    }
    //定義一個更新顯示的方法
    private void updateShow(Location location) {
        if (location != null) {
            StringBuilder sb = new StringBuilder();
            sb.append("目前的位置資訊：\n");
            double a = location.getLongitude();
            if(a<=0){
                a = location.getLongitude()*-1;
            }
            sb.append("經度：" +  a + "\n");//顯示正數
            sb.append("緯度：" + location.getLatitude() + "\n");
            sb.append("高度：" + location.getAltitude() + "\n");
            sb.append("速度：" + location.getSpeed() + "\n");
            sb.append("方向：" + location.getBearing() + "\n");
            sb.append("定位精度：" + location.getAccuracy() + "\n");
            tv_show.setText(sb.toString());
        } else{
            tv_show.setText("");
        }
    }

    @SuppressLint("MissingPermission")
    private  void startLocation(){
        //從GPS擷取最近的定位資訊
        Location lc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        updateShow(lc);
        //設定間隔兩秒獲得一次GPS定位資訊
        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 8, new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                // 當GPS定位資訊發生改變時，更新定位
                updateShow(location);
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {
            }

            @Override
            public void onProviderEnabled(String provider) {
                // 當GPS LocationProvider可用時，更新定位
                updateShow(lm.getLastKnownLocation(provider));
            }

            @Override
            public void onProviderDisabled(String provider) {
                updateShow(null);
            }
        });
    }

    private boolean isGpsAble(LocationManager lm) {
        return lm.isProviderEnabled(android.location.LocationManager.GPS_PROVIDER) ? true : false;
    }

    //打開設定頁面讓使用者自己設定
    private void openGPS2() {
        Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
        startActivityForResult(intent, 0);
    }

}