Android中的接近传感器无法响应

Question

I am trying to build a simple Android application which updates the text of a textview when the proximity sensor values change. However the textview values remain the same despite bringing an object close to the sensor.

Here is my MainActivity.java code

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements SensorEventListener{



    private SensorManager mSensorManager;
    private Sensor mProximity;
    TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
// Get an instance of the sensor service, and use that to get an instance of
        // a particular sensor.
        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mProximity = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
        mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL);
        textView = (TextView) findViewById(R.id.newtext);

    }


    public final void onAccuracyChanged(Sensor sensor, int accuracy) {
        // Do something here if sensor accuracy changes.
    }


    public final void onSensorChanged(SensorEvent event) {
        float distance = event.values[0];
        textView.setText(""+event.values[0]);
        if (distance<3){
            textView.setText("near"+distance);
        }
        // Do something with this sensor data.
    }

    @Override
    protected void onResume() {
        // Register a listener for the sensor.
        super.onResume();
        mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL);
    }

    @Override
    protected void onPause() {
        // Be sure to unregister the sensor when the activity pauses.
        super.onPause();
        mSensorManager.unregisterListener(this);
    }
}

Here is my XML code:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.suzancruz.senapp.MainActivity">

    <TextView
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:id="@+id/newtext"
        android:text="hjkhjk"
        />

</LinearLayout>

Answer 1

Please change your logic in onSensorChanged method,

@Override
public void onSensorChanged(SensorEvent event) {
    if (event.sensor.getType() == Sensor.TYPE_PROXIMITY) {
        if (event.values[0] < mSensor.getMaximumRange()) {
            if (!wakeLock.isHeld()) {
                wakeLock.acquire();
            }
        } else {
            if (wakeLock.isHeld()) {
                wakeLock.release();
            }
        }
    }
}