Today I’m going to share a working Code to make a very simple Compass application for your android device.
Some android device (like Huawei Y300 and Lenovo P700i) does not have full support of motions sensors so this code will not work for them.
Some android device (like Huawei Y300 and Lenovo P700i) does not have full support of motions sensors so this code will not work for them.
Files Needed
You need to create your own compass image. For this example, I’m using a stock photo. Your image must be a PNG with transparent background, do not use this jpg file I used.
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Let’s Code
Here’s our MainActivity.java
01 | package com.example.compassapp; |
02 |
03 | import android.app.Activity; |
04 | import android.hardware.Sensor; |
05 | import android.hardware.SensorEvent; |
06 | import android.hardware.SensorEventListener; |
07 | import android.hardware.SensorManager; |
08 | import android.os.Bundle; |
09 | import android.view.animation.Animation; |
10 | import android.view.animation.RotateAnimation; |
11 | import android.widget.ImageView; |
12 | import android.widget.TextView; |
13 |
14 | public class MainActivity extends Activity implements SensorEventListener { |
15 |
16 | // define the display assembly compass picture |
17 | private ImageView image; |
18 |
19 | // record the compass picture angle turned |
20 | private float currentDegree = 0f; |
21 |
22 | // device sensor manager |
23 | private SensorManager mSensorManager; |
24 |
25 | TextView tvHeading; |
26 |
27 | @Override |
28 | protected void onCreate(Bundle savedInstanceState) { |
29 | super.onCreate(savedInstanceState); |
30 | setContentView(R.layout.activity_main); |
31 |
32 | // |
33 | image = (ImageView) findViewById(R.id.main_iv); |
34 |
35 | // TextView that will tell the user what degree is he heading |
36 | tvHeading = (TextView) findViewById(R.id.tvHeading); |
37 |
38 | // initialize your android device sensor capabilities |
39 | mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE); |
40 | } |
41 |
42 | @Override |
43 | protected void onResume() { |
44 | super.onResume(); |
45 |
46 | // for the system's orientation sensor registered listeners |
47 | mSensorManager.registerListener(this, mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION), |
48 | SensorManager.SENSOR_DELAY_GAME); |
49 | } |
50 |
51 | @Override |
52 | protected void onPause() { |
53 | super.onPause(); |
54 |
55 | // to stop the listener and save battery |
56 | mSensorManager.unregisterListener(this); |
57 | } |
58 |
59 | @Override |
60 | public void onSensorChanged(SensorEvent event) { |
61 |
62 | // get the angle around the z-axis rotated |
63 | float degree = Math.round(event.values[0]); |
64 |
65 | tvHeading.setText("Heading: " + Float.toString(degree) + " degrees"); |
66 |
67 | // create a rotation animation (reverse turn degree degrees) |
68 | RotateAnimation ra = new RotateAnimation( |
69 | currentDegree, |
70 | -degree, |
71 | Animation.RELATIVE_TO_SELF, 0.5f, |
72 | Animation.RELATIVE_TO_SELF, |
73 | 0.5f); |
74 |
75 | // how long the animation will take place |
76 | ra.setDuration(210); |
77 |
78 | // set the animation after the end of the reservation status |
79 | ra.setFillAfter(true); |
80 |
81 | // Start the animation |
82 | image.startAnimation(ra); |
83 | currentDegree = -degree; |
84 |
85 | } |
86 |
87 | @Override |
88 | public void onAccuracyChanged(Sensor sensor, int accuracy) { |
89 | // not in use |
90 | } |
91 | } |
Our layout file activity_main.xml
01 | <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" |
02 | android:layout_width="match_parent" |
03 | android:layout_height="match_parent" |
04 | android:background="#fff" > |
05 |
06 | <TextView |
07 | android:id="@+id/tvHeading" |
08 | android:layout_width="wrap_content" |
09 | android:layout_height="wrap_content" |
10 | android:layout_centerHorizontal="true" |
11 | android:layout_marginBottom="40dp" |
12 | android:layout_marginTop="20dp" |
13 | android:text="Heading: 0.0" /> |
14 |
15 | <ImageView |
16 | android:id="@+id/imageViewCompass" |
17 | android:layout_width="wrap_content" |
18 | android:layout_height="wrap_content" |
19 | android:layout_below="@+id/tvHeading" |
20 | android:layout_centerHorizontal="true" |
21 | android:src="@drawable/img_compass" /> |
22 |
23 | </RelativeLayout> |
Source Code Download
You can download this sample project here: CompassApp.zip
Some notes
My app orientation is locked to portrait mode. There are no special permissions in the Manifest file.
