Android sensor applications

First, the sensor application android4.0 above

This error java.lang.RuntimeException:Unable to start activity componentinfo{com.sensorget/com.sensorget.mainactivity}: Java.lang.NullPointerException

Cried, seemingly android4.0 above the main thread can not handle too many tasks, the system will force kill. So you should use a sub-thread to update ui!!

 PackageCom.sensorget;Importjava.util.List;ImportAndroid.annotation.SuppressLint;Importandroid.app.Activity;Importandroid.app.Fragment;ImportAndroid.content.Context;ImportAndroid.hardware.Sensor;ImportAndroid.hardware.SensorManager;ImportAndroid.os.Bundle;ImportAndroid.os.Handler;ImportAndroid.os.Message;ImportAndroid.view.LayoutInflater;ImportAndroid.view.Menu;ImportAndroid.view.MenuItem;ImportAndroid.view.View;ImportAndroid.view.ViewGroup;ImportAndroid.widget.TextView; @SuppressLint ("Handlerleak") Public classMainactivityextendsActivity {@Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_main); if(Savedinstancestate = =NULL) {Getfragmentmanager (). BeginTransaction (). Add (R.id.container,Newplaceholderfragment ()). commit (); }        NewThread (runnable). Start ();//Thread Execution! } Handler Handler=NewHandler () { Public voidhandlemessage (Message msg) {Super. Handlemessage (msg); Bundle Data=Msg.getdata (); String Val= Data.getstring ("Value"); //preparing the UI build for displaying informationTextView txt =(TextView) Findviewbyid (R.ID.TEXTVIEW1);        Txt.settext (Val);    }    }; Runnable Runnable=NewRunnable () {@Override Public voidrun () {Message msg=NewMessage (); Bundle Data=NewBundle (); Data.putstring ("Value", Initview ());            Msg.setdata (data);        Handler.sendmessage (msg);    }    }; PrivateString Initview () {//get the Sensor manager from System servicesSensormanager SM =(Sensormanager) Getsystemservice (Context.sensor_service); //get the full list of sensors from the sensor managerList<sensor> allsensors =sm.getsensorlist (Sensor.type_all); String Str= ""; //shows how many sensors there are//Txt.settext ("detected by the phone has" + allsensors.size () + "sensors, they are: \ n");str + = "detected by the phone has" + allsensors.size () + "sensors, they are: \ n"; //display specific information for each sensor         for(Sensor s:allsensors) {String tempstring= "\ n" + "Device Name:" + s.getname () + "\ n" + "Device version:" + s.getversion () + "\ n" + "Supplier:" + S.getvendor () + "\ n"; System.out.println ("Sensor:" +S.gettype ()); Switch(S.gettype ()) { CaseSensor.TYPE_ACCELEROMETER:str+ = S.gettype () + "Accelerometer Accelerometer" +tempstring;  Break;  CaseSensor.TYPE_AMBIENT_TEMPERATURE:str+ = S.gettype () + "Temperature sensor temperature" +tempstring;  Break;  CaseSensor.TYPE_GRAVITY:str+ = S.gettype () + "Gravity sensor gravity" +tempstring;  Break;  CaseSensor.TYPE_GYROSCOPE:str+ = S.gettype () + "Gyro sensor gyroscope" +tempstring;  Break;  CaseSensor.TYPE_LIGHT:str+ = S.gettype () + "ambient light sensor lights" +tempstring;  Break;  CaseSensor.TYPE_LINEAR_ACCELERATION:str+ = S.gettype () + "linear acceleration sensor linear_accelerometer" +tempstring;  Break;  CaseSensor.TYPE_MAGNETIC_FIELD:str+ = S.gettype () + "electromagnetic field sensor magnetic field" +tempstring;  Break;  CaseSensor.TYPE_PRESSURE:str+ = S.gettype () + "pressure sensor pressure" +tempstring;  Break;  CaseSensor.TYPE_PROXIMITY:str+ = S.gettype () + "distance sensor proximity" +tempstring;  Break;  CaseSensor.TYPE_RELATIVE_HUMIDITY:str+ = S.gettype () + "humidity sensor relative_humidity" +tempstring;  Break;  CaseSensor.TYPE_ROTATION_VECTOR:str+ = S.gettype () + "rotational vector sensor Rotation_vector" +tempstring;  Break; default: Str+ = S.gettype () + "Unknown sensor" +tempstring;  Break; }        }        returnstr; } @Override Public BooleanOncreateoptionsmenu (Menu menu) {//inflate the menu; This adds items to the action bar if it is present.getmenuinflater (). Inflate (R.menu.main, menu); return true; } @Override Public Booleanonoptionsitemselected (MenuItem item) {//Handle Action Bar item clicks here. The Action Bar would//automatically handle clicks on the Home/up button, so long//As you specify a the parent activity in Androidmanifest.xml.        intID =Item.getitemid (); if(id = =r.id.action_settings) {            return true; }        return Super. onoptionsitemselected (item); }    /*** A placeholder fragment containing a simple view. */     Public Static classPlaceholderfragmentextendsFragment { Publicplaceholderfragment () {} @Override PublicView Oncreateview (layoutinflater inflater, ViewGroup container, Bundle savedinstancestate) { View Rootview=inflater.inflate (R.layout.fragment_main, container,false); returnRootview; }    }}

Android sensor applications