Question

我是一名学生工程师，我目前正在开发一款应用。我已经为秒表写了一些代码，但有人可以帮我吗？我想建立一个秒表，它在接近传感器未激活时启动，并在接近传感器激活时停止。这就是我已经拥有的：

package com.example.michiel.myapplication2;


import android.app.Activity;
import android.graphics.Color;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;

import static com.google.android.gms.common.api.GoogleApiClient.Builder;


public class MainActivity extends Activity implements SensorEventListener{


    Button butnstart, butnreset;
    TextView time;
    TextView test;
    long starttime = 0L;
    long timeInMilliseconds = 0L;
    long timeSwapBuff = 0L;
    long updatedtime = 0L;
    int t = 1;
    int secs = 0;
    int mins = 0;
    int milliseconds = 0;
    Handler handler = new Handler();

    // sensor
    SensorManager sm;
    Sensor proxSensor;

    boolean afstand;




    /**
     * ATTENTION: This was auto-generated to implement the App Indexing API.
     * See https://g.co/AppIndexing/AndroidStudio for more information.
     */
    private GoogleApiClient client;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        butnstart = (Button) findViewById(R.id.start);
        butnreset = (Button) findViewById(R.id.reset);
        time = (TextView) findViewById(R.id.timer);

        //sensor
        sm=(SensorManager)getSystemService(SENSOR_SERVICE);
        proxSensor=sm.getDefaultSensor(Sensor.TYPE_PROXIMITY);
        test = (TextView) findViewById(R.id.test);
        sm.registerListener (this,proxSensor, SensorManager.SENSOR_DELAY_NORMAL);



        butnstart.setOnClickListener(new OnClickListener() {


            @Override
            public void onClick(View v) {


                if (t == 1) {
                    butnstart.setText("Pause");
                    starttime = SystemClock.uptimeMillis();
                    handler.postDelayed(updateTimer, 0);
                    t = 0;
                } else {
                    butnstart.setText("Start");
                    time.setTextColor(Color.BLUE);
                    timeSwapBuff += timeInMilliseconds;
                    handler.removeCallbacks(updateTimer);
                    t = 1;
                }
            }
        });

        butnreset.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                starttime = 0L;
                timeInMilliseconds = 0L;
                timeSwapBuff = 0L;
                updatedtime = 0L;
                t = 1;
                secs = 0;
                mins = 0;
                milliseconds = 0;
                butnstart.setText("Start");
                handler.removeCallbacks(updateTimer);
                time.setText("00:00:00");
            }
        });
        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client = new Builder(this).addApi(AppIndex.API).build();
    }

    public Runnable updateTimer = new Runnable() {
        public void run() {
            timeInMilliseconds = SystemClock.uptimeMillis() - starttime;
            updatedtime = timeSwapBuff + timeInMilliseconds;
            secs = (int) (updatedtime / 1000);
            mins = secs / 60;
            secs = secs % 60;
            milliseconds = (int) (updatedtime % 1000);
            time.setText("" + mins + ":" + String.format("%02d", secs) + ":"
                    + String.format("%03d", milliseconds));
            time.setTextColor(Color.RED);
            handler.postDelayed(this, 0);
        }
    };


    @Override
    public void onStart() {
        super.onStart();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client.connect();
        Action viewAction = Action.newAction(
                Action.TYPE_VIEW, // TODO: choose an action type.
                "Main Page", // TODO: Define a title for the content shown.
                // TODO: If you have web page content that matches this app activity's content,
                // make sure this auto-generated web page URL is correct.
                // Otherwise, set the URL to null.
                Uri.parse("http://host/path"),
                // TODO: Make sure this auto-generated app URL is correct.
                Uri.parse("android-app://com.example.michiel.myapplication2/http/host/path")
        );
        AppIndex.AppIndexApi.start(client, viewAction);
    }

    @Override
    public void onStop() {
        super.onStop();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        Action viewAction = Action.newAction(
                Action.TYPE_VIEW, // TODO: choose an action type.
                "Main Page", // TODO: Define a title for the content shown.
                // TODO: If you have web page content that matches this app activity's content,
                // make sure this auto-generated web page URL is correct.
                // Otherwise, set the URL to null.
                Uri.parse("http://host/path"),
                // TODO: Make sure this auto-generated app URL is correct.
                Uri.parse("android-app://com.example.michiel.myapplication2/http/host/path")
        );
        AppIndex.AppIndexApi.end(client, viewAction);
        client.disconnect();
    }

    @Override
    public void onSensorChanged(SensorEvent event) {

        if (afstand==true){
            afstand=false;
        }
        else afstand =true;

        test.setText("detectie");

    }

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


    }
}

Answer 1

似乎SensorEvent必须具有值参数，以cm为单位显示到对象的距离。所以，你必须这样做smtng：

if(event.values[0] <= 2){
//do something
}

有关详细信息，请查看此页面： https://developer.android.com/guide/topics/sensors/sensors_position.html

秒表Android应用程序，从接近传感器开始

1 个答案: