如何顯示傳感器數據值

Question

您好我對android非常陌生。我正在嘗試編寫一個可以收集傳感器數據的代碼。我嘗試了「http://developer.android.com/guide/topics/sensors/sensors_overview.html」中給出的示例。現在，我在手機（Samsung Galaxy S3）上安裝了apk文件，該應用程序運行但崩潰。這是我寫的代碼：

每當我把行「tv1.setText（Float.toString（lux））;應用程序崩潰;」在onSensoeChanged（）方法中。請告訴我在這裏做錯了什麼，以及如何更正代碼。

這是我第一篇文章在這個網站。對於張貼問題，任何不正確的格式道歉

感謝

'

package com.example.sensordata; 

import android.support.v7.app.ActionBarActivity; 
import android.support.v7.app.ActionBar; 
import android.support.v4.app.Fragment; 
import android.app.Activity; 
import android.content.Context; 
import android.hardware.Sensor; 
import android.hardware.SensorEvent; 
import android.hardware.SensorEventListener; 
import android.hardware.SensorManager; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.TextView; 
import android.os.Build; 

public class MainActivity extends Activity implements SensorEventListener { 

     public SensorManager mSensorManager; 
     public Sensor mLight; 

     public TextView tv1; 
     //public TextView tv2; 

     @Override 
     public final void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); 
     mLight = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT); 

     tv1 = (TextView) findViewById(R.id.text1); 
     //tv2 = (TextView) findViewById(R.id.text2);  

     } 

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

     @Override 
     public final void onSensorChanged(SensorEvent event) { 
     // The light sensor returns a single value. 
     // Many sensors return 3 values, one for each axis. 
      synchronized (this) { 
       float lux = event.values[0]; 
       // Do something with this sensor value. 
       //tv1 = (TextView) findViewById(R.id.text1); 
       tv1.setText(Float.toString(lux)); 

      } 

     } 

     @Override 
     protected void onResume() { 
     super.onResume(); 
     mSensorManager.registerListener(this, mLight, SensorManager.SENSOR_DELAY_NORMAL); 

     } 

     @Override 
     protected void onPause() { 
     super.onPause(); 
     mSensorManager.unregisterListener(this); 
     } 
    } 
` 

Answer 1

嘗試tv1.setText(String.valueOf(lux));代替tv1.setText(Float.toString(lux));

Answer 2

 runOnUiThread(new Runnable() { 

     @Override 
     public void run() { 
      tv1.setText(Float.toString(lux)); 
     } 
    }); 

Answer 3

您的所有傳感器前應

setContentView(R.layout.activity_main); 

初始化

或者你的程序會給運行時錯誤和崩潰。

你的代碼可能是這個樣子，

public class MainActivity extends Activity implements SensorEventListener { 

    public SensorManager mSensorManager; 
    public Sensor mLight; 

    public TextView tv1; 
    //public TextView tv2; 

    @Override 
    public final void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    initializesensor(); 

    setContentView(R.layout.activity_main); 

    tv1 = (TextView) findViewById(R.id.text1); 

    } 

    public void initializesensor(){ 
    //write all sensor code here(excluding sensor stopping method) 
    }