安卓无法解析片段中的方法setText（java.lang.String）

Question

我正在使用计步器计算设备上次重新启动后的步数

我已经创建了一个textView，我想将它的文本设置为使用传感器时的步数。（我的文本视图称为计数）

我的代码是：

@Override
public void onSensorChanged(SensorEvent event) {
    if (activityRunning) {
        count.setText(String.valueOf(event.values[0]));
    }

我在这里得到一个错误Cannot resolve method setText(java.lang.String)

如果有助于解决这个问题，我可以发布课堂上的其他内容

谢谢

这是本课程的其余部分：

public class Tab3 extends Fragment implements SensorEventListener {

private SensorManager sensorManager;
private TextView textView;
boolean activityRunning;
private Button buttonReturn;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.tab3, container, false);

    TextView count = (TextView) getActivity().findViewById(R.id.count);

    sensorManager = (SensorManager) getActivity().getSystemService(Context.SENSOR_SERVICE);

    getActivity().getSystemService(Context.SENSOR_SERVICE);

    return rootView;
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
}

@Override
public void onResume() {
    super.onResume();
    activityRunning = true;
    Sensor countSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
    if (countSensor != null) {
        sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_UI);
    } else {
        Toast.makeText(getActivity(), "Count sensor not available!", Toast.LENGTH_LONG).show();
    }

}

@Override
public void onPause() {
    super.onPause();
    activityRunning = false;
}

@Override
public void onSensorChanged(SensorEvent event) {
    if (activityRunning) {
        count.setText(String.valueOf(event.values[0]));
    }

}

@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {

}
}

这是与此类关联的XML文件：

<RelativeLayout xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
xmlns:tools="http://schemas.安卓.com/tools"
安卓:layout_width="match_parent"
安卓:layout_height="match_parent"
安卓:paddingBottom="@dimen/activity_vertical_margin"
安卓:paddingLeft="@dimen/activity_horizontal_margin"
安卓:paddingRight="@dimen/activity_horizontal_margin"
安卓:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.application.placepicker.TabbedActivity$PlaceholderFragment">

<LinearLayout
    安卓:layout_width="match_parent"
    安卓:layout_height="wrap_content"
    安卓:orientation="vertical"
    安卓:layout_marginTop="114dp"
    安卓:gravity="center"
    安卓:layout_alignParentTop="true"
    安卓:layout_alignParentStart="true">

    <TextView
        安卓:id="@+id/textLogin"
        安卓:layout_width="wrap_content"
        安卓:layout_height="wrap_content"
        安卓:layout_gravity="center_horizontal"
        安卓:text="Step counter"
        安卓:textSize="40sp"
        安卓:textColor="@color/colorAccent"
        安卓:fontFamily="sans-serif"
        安卓:textAppearance="?安卓:attr/textAppearanceLarge" />

    <TextView
        安卓:layout_width="wrap_content"
        安卓:layout_height="wrap_content"
        安卓:layout_marginTop="33dp"
        安卓:layout_gravity="center_horizontal"
        安卓:textSize="26dp"
        安卓:text="Steps walked so far today:"
        安卓:textColor="@color/colorAccent" />

    <TextView
        安卓:id="@+id/count"
        安卓:layout_width="wrap_content"
        安卓:layout_height="wrap_content"
        安卓:layout_marginTop="40dp"
        安卓:layout_marginLeft="50dp"
        安卓:text="---"
        安卓:textColor="@color/colorAccent"
        安卓:textSize="36dp" />

</LinearLayout>

Answer 1

将“count”从“onCreateView”中带出，以便在“onSensorChanged”中可以访问它

public class Tab3 extends Fragment implements SensorEventListener {
 private SensorManager sensorManager;
 private TextView textView;
 boolean activityRunning;
 private Button buttonReturn;

private TextView count ;//<  add this

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.tab3, container, false);

    //define count global 
    count = (TextView)rootView.findViewById(R.id.count);

    sensorManager = (SensorManager) getActivity().getSystemService(Context.SENSOR_SERVICE);

    getActivity().getSystemService(Context.SENSOR_SERVICE);

    return rootView;
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
}

@Override
public void onResume() {
    super.onResume();
    activityRunning = true;
    Sensor countSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
    if (countSensor != null) {
        sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_UI);
    } else {
        Toast.makeText(getActivity(), "Count sensor not available!", Toast.LENGTH_LONG).show();
    }

}

@Override
public void onPause() {
    super.onPause();
    activityRunning = false;
}

@Override
public void onSensorChanged(SensorEvent event) {
    if (activityRunning) {
        count.setText(String.valueOf(event.values[0]));
    }

}

@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {

}
}

Answer 2

你如何定义你的“计数”

如果我们假设您已正确定义TextView，则会在null对象中出现错误， 因此，最好将代码更改为以下内容：

   count.setText(""+event.values[0]);

Answer 3

改变

private TextView textView;

到

private TextView count;

改变

TextView count = (TextView) getActivity().findViewById(R.id.count);

到

count = (TextView) getActivity().findViewById(R.id.count);