[Android] 取得裝置的定位

要取得定位，必須用到 Google Play Services，所以先檢查 SDK Manager，是否已安裝 Google Play Services。

build.gradle，加入

compile 'com.google.android.gms:play-services-location:11.6.2'

 

 

您的版本可能會跟我不同，因為會一直改版。

注意：
儘量不要加入所有的 Google Play Services API，也就是說，不要寫下面這種形式 —-

compile 'com.google.android.gms:play-services:11.6.2'

這樣很容易超出 65K 限制，在您按下 Sync Project with Gradle Files 時會回應錯誤，建議只加入您所需要的 Google Play Services。

---

開放權限

<manifest
 xmlns:android="http://schemas.android.com/apk/res/android"
 ... >

 ...
 ...

 <!-- 精確定位，就是 GPS -->
 <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
 <!-- 約略定位，就是 WI-FI -->
 <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

 ...
 ...

---

activity_main.xml 版面

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical" >

 <!-- 經度 -->
 <TextView
 android:id="@+id/longitude_text"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_marginLeft="10dp"
 android:layout_marginStart="10dp"
 android:textIsSelectable="true" />

 <!-- 緯度 -->
 <TextView
 android:id="@+id/latitude_text"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_marginLeft="10dp"
 android:layout_marginStart="10dp"
 android:textIsSelectable="true" />
</LinearLayout>

---

GoogleApiClient 提供了 Builder 和 ConnectionCallbacks、OnConnectionFailedListener 兩個 Interface，所以我們要以 Builder 建立 GoogleApiClient 這個 instance 和 實做 ConnectionCallbacks、OnConnectionFailedListener。

範列程式：

// 記得 import 下面這幾個
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener;
import com.google.android.gms.location.LocationServices;
 
public class LocationMainActivity extends AppCompatActivity implements ConnectionCallbacks, OnConnectionFailedListener
{
    protected static final String TAG = "MainActivity";
 
    protected GoogleApiClient mGoogleApiClient;
    protected Location mLastLocation;
 
    protected String mLatitudeLabel;
    protected String mLongitudeLabel;
    protected TextView mLatitudeText;
    protected TextView mLongitudeText;
 
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_location_main);
 
        mLatitudeLabel = "緯度";
        mLongitudeLabel = "經度";
        mLatitudeText = (TextView) findViewById((R.id.latitude_text));
        mLongitudeText = (TextView) findViewById((R.id.longitude_text));
 
        buildGoogleApiClient();
    }
 
    protected synchronized void buildGoogleApiClient()
    {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }
 
    @Override
    protected void onStart()
    {
        super.onStart();
        mGoogleApiClient.connect();
    }
 
    @Override
    protected void onStop() 
    {
        super.onStop();
        if (mGoogleApiClient.isConnected()) 
        {
            mGoogleApiClient.disconnect();
        }
    }
 
 
    // 當 GoogleApiClient 連上 Google Play Service 後要執行的動作
    @Override
    public void onConnected(Bundle connectionHint)
    {
        // 這行指令在 IDE 會出現紅線，不過仍可正常執行，可不予理會
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (mLastLocation != null)
            {
                mLatitudeText.setText(String.format("%s: %f", mLatitudeLabel, mLastLocation.getLatitude()));
                mLongitudeText.setText(String.format("%s: %f", mLongitudeLabel, mLastLocation.getLongitude()));
            }
        else
            {
                Toast.makeText(this, "偵測不到定位，請確認定位功能已開啟。", Toast.LENGTH_LONG).show();
            }
    }
 
    @Override
    public void onConnectionFailed(ConnectionResult result)
    {
        Log.i(TAG, "Connection failed: ConnectionResult.getErrorCode() = " + result.getErrorCode());
    }
 
 
    @Override
    public void onConnectionSuspended(int cause)
    {
        Log.i(TAG, "Connection suspended");
        mGoogleApiClient.connect();
    }
}

 

 

資料來源：

http://oldgrayduck.blogspot.tw/2016/06/android-studio-android.html