Question

您好，我正在尝试学习 RxAndroidBLE 并阅读单个特征使用以下代码：

                String macAddress = "84:CC:A8:2E:24:6A";
                RxBleDevice device = rxBleClient.getBleDevice(macAddress);
                Disposable disposable = device.establishConnection(false) // <-- autoConnect flag
                        .subscribe(
                                rxBleConnection -> {
                                // All GATT operations are done through the rxBleConnection.
//                                    Toast.makeText(MainActivity.this, "connected" , Toast.LENGTH_LONG).show();
                                },
                                throwable -> {
                                    // Handle an error here.
                                    Toast.makeText(MainActivity.this, "connect error" + throwable.getMessage(), Toast.LENGTH_LONG).show();
                                }
                        );
// When done... dispose and forget about connection teardown :)
                disposable.dispose();
                // Read characteristic
                device.establishConnection(false)
                        .flatMapSingle(rxBleConnection -> rxBleConnection.readCharacteristic(UUID.fromString(PIN_UUID))
 //                      .observeOn(AndroidSchedulers.mainThread())
                        .subscribe(
                                characteristicValue -> {
                                    // Read characteristic value.
                                    rtext.setText(new String(characteristicValue));
                                },
                                throwable -> {
                                    Toast.makeText(MainActivity.this, "read error" + throwable.getMessage(), Toast.LENGTH_LONG).show();
                                    // Handle an error here.
                                }
                        ));

这给出了错误：

                    .flatMapSingle(rxBleConnection -> rxBleConnection.readCharacteristic(UUID.fromString(PIN_UUID))
                                  ^
(argument mismatch; bad return type in lambda expression
  Disposable cannot be converted to SingleSource<? extends R>)

其中 R,T 是类型变量： R extends Object 在方法 flatMapSingle(Function>) 中声明 T 扩展 Observable 类中声明的对象

我尝试使用 .flatMap 和 .flatMapSingle，但都给出了相同的错误。我也想知道我是否取消注释该行： .observeOn(AndroidSchedulers.mainThread())

AndroidSchedulers 未定义且导入行不存在：导入 io.reactivex.android.schedulers.AndroidSchedulers;

Answer 1

显然你把括号放错了地方。以 .flatMapSingle 开头的行在代码段末尾关闭。

                device.establishConnection(false)
// [Answer] The line below should be closed but instead the closing bracket is ...
                        .flatMapSingle(rxBleConnection -> rxBleConnection.readCharacteristic(UUID.fromString(PIN_UUID)) 
 //                      .observeOn(AndroidSchedulers.mainThread())
                        .subscribe(
                                characteristicValue -> {
                                    // Read characteristic value.
                                    rtext.setText(new String(characteristicValue));
                                },
                                throwable -> {
                                    Toast.makeText(MainActivity.this, "read error" + throwable.getMessage(), Toast.LENGTH_LONG).show();
                                    // Handle an error here.
                                }
// [Answer] ... is closed below! Thus you try to return a Disposable where a Single is expected
                        ));

尝试使用以下内容：

                device.establishConnection(false)
                        .flatMapSingle(rxBleConnection -> rxBleConnection.readCharacteristic(UUID.fromString(PIN_UUID))) 
 //                      .observeOn(AndroidSchedulers.mainThread())
                        .subscribe(
                                characteristicValue -> {
                                    // Read characteristic value.
                                    rtext.setText(new String(characteristicValue));
                                },
                                throwable -> {
                                    Toast.makeText(MainActivity.this, "read error" + throwable.getMessage(), Toast.LENGTH_LONG).show();
                                    // Handle an error here.
                                }
                        );

RxAndroidBLE 尝试读取特性给出编译错误

1 个答案: