存取 Google API

當您想要呼叫 如要使用 Google Play 登入或機器學習套件等 Google Play 服務，您必須先 建立 API 用戶端物件的執行個體。這些物件會自動管理 及 Google Play 服務之間的連線如果有可用的連線，每個 API 用戶端物件會依序執行要求。否則，用戶端物件佇列 要求。除非說明文件另有註明，否則用戶端物件是低成本的 建構方式每次要叫用新的 API 用戶端時 API 方法。

本指南將說明如何向採用 Google Cloud 技術的 SDK 發出 API 呼叫 存取 Google Play 服務，包括如何存取不支援 需要授權和 授權。

開始使用

如要開始使用，請在應用程式專案中新增必要的工具和依附元件。 ，其運作方式為設定 Google Play 服務。

不需要授權時存取

如要使用不需要 API 授權的服務，請取得 服務的用戶端物件，並將目前 Context 或 目前 Activity。 執行任何 API 呼叫前，系統會提示使用者升級 Google Play 或提供免付費服務

例如，使用整合式位置查詢取得裝置的最後已知位置 針對 Android 的供應商，新增以下程式碼片段所示的邏輯：

Kotlin

// Code required for requesting location permissions omitted for brevity.
val client = LocationServices.getFusedLocationProviderClient(this)

// Get the last known location. In some rare situations, this can be null.
client.lastLocation.addOnSuccessListener { location : Location? ->
    location?.let {
        // Logic to handle location object.
    }
}

Java

// Code required for requesting location permissions omitted for brevity.
FusedLocationProviderClient client =
        LocationServices.getFusedLocationProviderClient(this);

// Get the last known location. In some rare situations, this can be null.
client.getLastLocation()
        .addOnSuccessListener(this, location -> {
            if (location != null) {
                // Logic to handle location object.
            }
        });

在需要授權時存取

如要存取需要使用者授權的服務，請完成下列步驟 步驟：

1. 讓使用者登入。
2. 針對服務所需的範圍要求存取權限。
3. 取得服務用戶端物件的例項，並將使用者的 GoogleSignInAccount敬上 加上 Context 或 Activity 物件。

以下範例是實作 Google Analytics 4 的 Fit API。如要在完整專案中查看類似的實作項目， 查看主要活動 BasicHistoryApiKotlin App Engine 應用程式

Kotlin

class FitFragment : Fragment() {
    private val fitnessOptions: FitnessOptions by lazy {
        FitnessOptions.builder()
            .addDataType(DataType.TYPE_STEP_COUNT_CUMULATIVE)
            .addDataType(DataType.TYPE_STEP_COUNT_DELTA)
            .build()
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        fitSignIn()
    }

    /*
     * Checks whether the user is signed in. If so, executes the specified
     * function. If the user is not signed in, initiates the sign-in flow,
     * specifying the function to execute after the user signs in.
     */
    private fun fitSignIn() {
        if (oAuthPermissionsApproved()) {
            readDailySteps()
        } else {
            GoogleSignIn.requestPermissions(
                this,
                SIGN_IN_REQUEST_CODE,
                getGoogleAccount(),
                fitnessOptions
            )
        }
    }

    private fun oAuthPermissionsApproved() =
        GoogleSignIn.hasPermissions(getGoogleAccount(), fitnessOptions)

    /*
     * Gets a Google account for use in creating the fitness client. This is
     * achieved by either using the last signed-in account, or if necessary,
     * prompting the user to sign in. It's better to use the
     * getAccountForExtension() method instead of the getLastSignedInAccount()
     * method because the latter can return null if there has been no sign in
     * before.
     */
    private fun getGoogleAccount(): GoogleSignInAccount =
        GoogleSignIn.getAccountForExtension(requireContext(), fitnessOptions)

    /*
     * Handles the callback from the OAuth sign in flow, executing the function
     * after sign-in is complete.
     */
    override fun onActivityResult(
            requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        when (resultCode) {
            RESULT_OK -> {
                readDailySteps()
            }
            else -> {
                // Handle error.
            }
        }
    }

    /*
     * Reads the current daily step total.
     */
    private fun readDailySteps() {
        Fitness.getHistoryClient(requireContext(), getGoogleAccount())
            .readDailyTotal(DataType.TYPE_STEP_COUNT_DELTA)
            .addOnSuccessListener { dataSet ->
                val total = when {
                    dataSet.isEmpty -> 0
                    else -> dataSet.dataPoints.first()
                            .getValue(Field.FIELD_STEPS).asInt()
                }

                Log.i(TAG, "Total steps: $total")
            }
            .addOnFailureListener { e ->
                Log.w(TAG, "There was a problem getting the step count.", e)
            }
    }

    companion object {
        const val SIGN_IN_REQUEST_CODE = 1001
    }
}

Java

public class FitFragment extends Fragment {
    private final FitnessOptions fitnessOptions = FitnessOptions.builder()
            .addDataType(DataType.TYPE_STEP_COUNT_CUMULATIVE)
            .addDataType(DataType.TYPE_STEP_COUNT_DELTA)
            .build();

    @Override
    public void onViewCreated(
            @NotNull View view, @Nullable Bundle savedInstanceState) {
        fitSignIn();
    }

    /*
     * Checks whether the user is signed in. If so, executes the specified
     * function. If the user is not signed in, initiates the sign-in flow,
     * specifying the function to execute after the user signs in.
     */
    private void fitSignIn() {
        if (oAuthPermissionsApproved()) {
            readDailySteps();
        } else {
            GoogleSignIn.requestPermissions(this, SIGN_IN_REQUEST_CODE,
                    getGoogleAccount(), fitnessOptions);
        }
    }

    private boolean oAuthPermissionsApproved() {
        return GoogleSignIn.hasPermissions(getGoogleAccount(), fitnessOptions);
    }

    /*
     * Gets a Google account for use in creating the fitness client. This is
     * achieved by either using the last signed-in account, or if necessary,
     * prompting the user to sign in. It's better to use the
     * getAccountForExtension() method instead of the getLastSignedInAccount()
     * method because the latter can return null if there has been no sign in
     * before.
     */
    private GoogleSignInAccount getGoogleAccount() {
        return GoogleSignIn.getAccountForExtension(
                requireContext(), fitnessOptions);
    }

    /*
     * Handles the callback from the OAuth sign in flow, executing the function
     * after sign-in is complete.
     */
    @Override
    public void onActivityResult(
            int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            readDailySteps();
        } else {
            // Handle error.
        }
    }

    /*
     * Reads the current daily step total.
     */
    private void readDailySteps() {
        AtomicInteger total = new AtomicInteger();
        Fitness.getHistoryClient(requireContext(), getGoogleAccount())
                .readDailyTotal(DataType.TYPE_STEP_COUNT_DELTA)
                .addOnSuccessListener(dataSet -> {
                    if (!dataSet.isEmpty())
                        total.set(Integer.parseInt(dataSet.getDataPoints()
                                .get(0).getValue(FIELD_STEPS).toString()));
                        Log.i(TAG, "Total steps: $total");
                })
                .addOnFailureListener(e -> {
                    Log.w(TAG, "There was a problem getting the step count.", e);
                });
    }

    private static final int SIGN_IN_REQUEST_CODE = 1001;
}

檢查 API 可用性

在應用程式中啟用需要 Google Play 服務的功能 API，包括檢查裝置是否可使用 API。方法如下 呼叫 checkApiAvailability()。

注意： 只有在需要停用應用程式中的特定功能時，才需要執行這項檢查 在 API 無法使用時傳送快訊除了不使用 請先執行這項檢查，因為如果 API 。

下列程式碼片段說明如何檢查 整合式位置預測提供工具。

Kotlin

fun getLastLocationIfApiAvailable(context: Context?): Task<Location>? {
    val client = getFusedLocationProviderClient(context)
    return GoogleApiAvailability.getInstance()
        .checkApiAvailability(client)
        .onSuccessTask { _ -> client.lastLocation }
        .addOnFailureListener { _ -> Log.d(TAG, "Location unavailable.")}
}

Java

public Task<Location> getLastLocationIfApiAvailable(Context context) {
    FusedLocationProviderClient client =
            getFusedLocationProviderClient(context);
    return GoogleApiAvailability.getInstance()
            .checkApiAvailability(client)
            .onSuccessTask(unused -> client.getLastLocation())
            .addOnFailureListener(e -> Log.d(TAG, "Location unavailable."));
}