我想制作一个应用程序，而且我是android新手。 我有10张照片。 当我摇动手机时，我希望每天用随机方法显示其中一张图片。 我写了摇动代码并随机显示这些图片，但我不能每天都展示其中一张。 你能帮我解释一下共享偏好的代码吗？
public class MainAccelerometer extends Activity implements AccelerometerListener{
ImageView favorit;
ImageView img;
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
favorit = (ImageView)findViewById(R.id.favorit);
img = (ImageView)findViewById(R.id.img);
// Check onResume Method to start accelerometer listener
}
public void onAccelerationChanged(float x, float y, float z) {
// TODO Auto-generated method stub
}
public void onShake(float force) {
Random rand = new Random();
int rndInt = rand.nextInt(10) + 1; // n = the number of images, that start at idx 1
String imgName = "img" + rndInt;
int id = getResources().getIdentifier(imgName, "drawable", getPackageName());
img.setImageResource(id);
// Do your stuff here
// Called when Motion Detected
Toast.makeText(getBaseContext(), "shake",
Toast.LENGTH_SHORT).show();
favorit.setBackgroundResource(R.drawable.img2);
}
@Override
public void onResume() {
super.onResume();
Toast.makeText(getBaseContext(), "onResume Accelerometer Started",
Toast.LENGTH_SHORT).show();
//Check device supported Accelerometer senssor or not
if (AccelerometerManager.isSupported(this)) {
//Start Accelerometer Listening
AccelerometerManager.startListening(this);
}
}
@Override
public void onStop() {
super.onStop();
//Check device supported Accelerometer senssor or not
if (AccelerometerManager.isListening()) {
//Start Accelerometer Listening
AccelerometerManager.stopListening();
Toast.makeText(getBaseContext(), "onStop Accelerometer Stoped",
Toast.LENGTH_SHORT).show();
}
}
@Override
public void onDestroy() {
super.onDestroy();
Log.i("Sensor", "Service distroy");
//Check device supported Accelerometer senssor or not
if (AccelerometerManager.isListening()) {
//Start Accelerometer Listening
AccelerometerManager.stopListening();
Toast.makeText(getBaseContext(), "onDestroy Accelerometer Stoped",
Toast.LENGTH_SHORT).show();
}
}}
和其他班级
public class AccelerometerManager {
private static Context aContext=null;
/** Accuracy configuration */
private static float threshold = 15.0f;
private static int interval = 200;
private static Sensor sensor;
private static SensorManager sensorManager;
// you could use an OrientationListener array instead
// if you plans to use more than one listener
private static AccelerometerListener listener;
/** indicates whether or not Accelerometer Sensor is supported */
private static Boolean supported;
/** indicates whether or not Accelerometer Sensor is running */
private static boolean running = false;
/**
* Returns true if the manager is listening to orientation changes
*/
public static boolean isListening() {
return running;
}
/**
* Unregisters listeners
*/
public static void stopListening() {
running = false;
try {
if (sensorManager != null && sensorEventListener != null) {
sensorManager.unregisterListener(sensorEventListener);
}
} catch (Exception e) {}
}
/**
* Returns true if at least one Accelerometer sensor is available
*/
public static boolean isSupported(Context context) {
aContext = context;
if (supported == null) {
if (aContext != null) {
sensorManager = (SensorManager) aContext.
getSystemService(Context.SENSOR_SERVICE);
// Get all sensors in device
List<Sensor> sensors = sensorManager.getSensorList(
Sensor.TYPE_ACCELEROMETER);
supported = new Boolean(sensors.size() > 0);
} else {
supported = Boolean.FALSE;
}
}
return supported;
}
/**
* Configure the listener for shaking
* @param threshold
* minimum acceleration variation for considering shaking
* @param interval
* minimum interval between to shake events
*/
public static void configure(int threshold, int interval) {
AccelerometerManager.threshold = threshold;
AccelerometerManager.interval = interval;
}
/**
* Registers a listener and start listening
* @param accelerometerListener
* callback for accelerometer events
*/
public static void startListening( AccelerometerListener accelerometerListener )
{
sensorManager = (SensorManager) aContext.
getSystemService(Context.SENSOR_SERVICE);
// Take all sensors in device
List<Sensor> sensors = sensorManager.getSensorList(
Sensor.TYPE_ACCELEROMETER);
if (sensors.size() > 0) {
sensor = sensors.get(0);
// Register Accelerometer Listener
running = sensorManager.registerListener(
sensorEventListener, sensor,
SensorManager.SENSOR_DELAY_GAME);
listener = accelerometerListener;
}
}
/**
* Configures threshold and interval
* And registers a listener and start listening
* @param accelerometerListener
* callback for accelerometer events
* @param threshold
* minimum acceleration variation for considering shaking
* @param interval
* minimum interval between to shake events
*/
public static void startListening(
AccelerometerListener accelerometerListener,
int threshold, int interval) {
configure(threshold, interval);
startListening(accelerometerListener);
}
/**
* The listener that listen to events from the accelerometer listener
*/
private static SensorEventListener sensorEventListener =
new SensorEventListener() {
private long now = 0;
private long timeDiff = 0;
private long lastUpdate = 0;
private long lastShake = 0;
private float x = 0;
private float y = 0;
private float z = 0;
private float lastX = 0;
private float lastY = 0;
private float lastZ = 0;
private float force = 0;
public void onAccuracyChanged(Sensor sensor, int accuracy) {}
public void onSensorChanged(SensorEvent event) {
// use the event timestamp as reference
// so the manager precision won't depends
// on the AccelerometerListener implementation
// processing time
now = event.timestamp;
x = event.values[0];
y = event.values[1];
z = event.values[2];
// if not interesting in shake events
// just remove the whole if then else block
if (lastUpdate == 0) {
lastUpdate = now;
lastShake = now;
lastX = x;
lastY = y;
lastZ = z;
Toast.makeText(aContext,"no",
Toast.LENGTH_SHORT).show();
} else {
timeDiff = now - lastUpdate;
if (timeDiff > 0) {
/*force = Math.abs(x + y + z - lastX - lastY - lastZ)
/ timeDiff;*/
force = Math.abs(x + y + z - lastX - lastY - lastZ);
if (Float.compare(force, threshold) >0 ) {
//Toast.makeText(Accelerometer.getContext(),
//(now-lastShake)+" >= "+interval, 1000).show();
if (now - lastShake >= interval) {
// trigger shake event
listener.onShake(force);
}
else
{
Toast.makeText(aContext,"No Motion detected",
Toast.LENGTH_SHORT).show();
}
lastShake = now;
}
lastX = x;
lastY = y;
lastZ = z;
lastUpdate = now;
}
else
{
Toast.makeText(aContext,"No Motion detected", Toast.LENGTH_SHORT).show();
}
}
// trigger change event
listener.onAccelerationChanged(x, y, z);
}
};}
答案 0 :(得分：0)
嘿你可以使用这个方法来计算当前的timeStamp并计算时差。
/*
* This method is calling to get current date
*
* */
public static String getCurrentDateWitTime() {
Calendar c = Calendar.getInstance();
// SimpleDateFormat df = new SimpleDateFormat(" yyyy-MM-dd'T'HH:mm:ss'Z");
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String formattedDate = df.format(c.getTime());
return formattedDate;
}
public static long getDifference(String oldTime)
{
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date oldDate = null;
try {
oldDate = dateFormat.parse(oldTime);
} catch (ParseException e) {
e.printStackTrace();
}
Date cDate = new Date();
Long timeDiff = cDate.getTime() - oldDate.getTime();
enter code here
long diffInSec = TimeUnit.MILLISECONDS.toSeconds(timeDiff);
return diffInSec;
}