Steps for Android to use a direction sensor to implement a compass

Step 1:Create a new project Compass and import a Compass image to the res/drawable-hdpi directory.

Step 2:Design the application UI, main. xml Copy codeThe Code is as follows: <SPAN style = "FONT-SIZE: 18px"> <STRONG> <? Xml version = "1.0" encoding = "UTF-8"?>
<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Android: orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
Android: gravity = "center"
>
<ImageView
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: src = "@ drawable/compass"
Android: id = "@ + id/imageView"
/>
</LinearLayout> </STRONG> </SPAN>

Step 3:MainActivity. javaCopy codeThe Code is as follows: 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. animation. Animation;
Import android. view. animation. RotateAnimation;
Import android. widget. ImageView;
Public class MainActivity extends Activity {
Private ImageView imageView;
/** Sensor manager */
Private SensorManager manager;
Private SensorListener listener = new SensorListener ();
@ Override
Public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. main );
ImageView = (ImageView) this. findViewById (R. id. imageView );
ImageView. setKeepScreenOn (true); // screen highlight
// Obtain the System Service (SENSOR_SERVICE) and return a SensorManager object.
Manager = (SensorManager) getSystemService (Context. SENSOR_SERVICE );
}
@ Override
Protected void onResume (){
/**
* Obtain the direction sensor.
* Get the SensorManager object.
*/
Sensor sensor = manager. getdefasensensor (Sensor. TYPE_ORIENTATION );
// The app registers the listener at the front-end.
Manager. registerListener (listener, sensor,
SensorManager. SENSOR_DELAY_GAME );
Super. onResume ();
}
@ Override
Protected void onPause (){
// Destroy the listener when the application is not in the foreground
Manager. unregisterListener (listener );
Super. onPause ();
}
Private final class SensorListener implements SensorEventListener {
Private float predegree = 0;
@ Override
Public void onSensorChanged (SensorEvent event ){
/**
* Values [0]: x-axis Acceleration
Values [1]: acceleration in y-axis direction
Values [2]: acceleration in the z-axis direction
*/
Float degree = event. values [0]; // stores the direction value
/** Animation effect */
RotateAnimation animation = new RotateAnimation (predegree, degree,
Animation. RELATIVE_TO_SELF, 0.5f, Animation. RELATIVE_TO_SELF, 0.5f );
Animation. setDuration (200 );
ImageView. startAnimation (animation );
Predegree =-degree;

/**
Float x = event. values [SensorManager. DATA_X];
Float y = event. values [SensorManager. DATA_Y];
Float z = event. values [SensorManager. DATA_Z];
Log. I ("XYZ", "x =" + (int) x + ", y =" + (int) y + ", z =" + (int) z );
*/
}
@ Override
Public void onAccuracyChanged (Sensor sensor, int accuracy ){
}
}
}

Step 4:AndroidManifest. xmlCopy codeThe Code is as follows: <SPAN style = "FONT-SIZE: 18px"> <STRONG> <? Xml version = "1.0" encoding = "UTF-8"?>
<Manifest xmlns: android = "http://schemas.android.com/apk/res/android"
Package = "cn. roco. sensor"
Android: versionCode = "1"
Android: versionName = "1.0" type = "codeph" text = "/codeph">
<Uses-sdk android: minSdkVersion = "8"/>
<Application android: icon = "@ drawable/icon" android: label = "@ string/app_name">
<Activity android: name = "MainActivity"
Android: label = "@ string/app_name">
<Intent-filter>
<Action android: name = "android. intent. action. MAIN"/>
<Category android: name = "android. intent. category. LAUNCHER"/>
</Intent-filter>
</Activity>
</Application>
</Manifest> </STRONG> </SPAN>