实例介绍
【实例简介】Android指南针app，可显示方向/海拔/大气压
【实例截图】
【核心代码】
package perseverance.li.compass;
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.location.Criteria;
import android.os.Bundle;
import android.os.Handler;
import android.text.TextUtils;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.view.animation.AccelerateInterpolator;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.Locale;
import perseverance.li.compass.view.CompassView;
public class CompassActivity extends Activity {
private final float MAX_ROATE_DEGREE = 1.0f;
private SensorManager mSensorManager;
private Sensor mOrientationSensor;
private Sensor mPressureSensor;
private float mDirection;
private float mTargetDirection;
private AccelerateInterpolator mInterpolator;
protected final Handler mHandler = new Handler();
private boolean mStopDrawing;
private boolean mChinease;
View mCompassView;
CompassView mPointer;
TextView mAltitudeTextView;
TextView mPressureTextView;
LinearLayout mDirectionLayout;
LinearLayout mAngleLayout;
protected Runnable mCompassViewUpdater = new Runnable() {
@Override
public void run() {
if (mPointer != null && !mStopDrawing) {
if (mDirection != mTargetDirection) {
// calculate the short routine
float to = mTargetDirection;
if (to - mDirection > 180) {
to -= 360;
} else if (to - mDirection < -180) {
to = 360;
}
// limit the max speed to MAX_ROTATE_DEGREE
float distance = to - mDirection;
if (Math.abs(distance) > MAX_ROATE_DEGREE) {
distance = distance > 0 ? MAX_ROATE_DEGREE : (-1.0f * MAX_ROATE_DEGREE);
}
// need to slow down if the distance is short
mDirection = normalizeDegree(mDirection
((to - mDirection) * mInterpolator.getInterpolation(Math
.abs(distance) > MAX_ROATE_DEGREE ? 0.4f : 0.3f)));
mPointer.updateDirection(mDirection);
}
updateDirection();
mHandler.postDelayed(mCompassViewUpdater, 20);
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.compass_layout);
initResources();
initServices();
}
@Override
protected void onResume() {
super.onResume();
if (mOrientationSensor != null) {
mSensorManager.registerListener(mOrientationSensorEventListener, mOrientationSensor,
SensorManager.SENSOR_DELAY_GAME);
}
if (mPressureSensor != null) {
mSensorManager.registerListener(mPressureSensorEventListener, mPressureSensor,
SensorManager.SENSOR_DELAY_GAME);
}
mStopDrawing = false;
mHandler.postDelayed(mCompassViewUpdater, 20);
}
@Override
protected void onPause() {
super.onPause();
mStopDrawing = true;
if (mOrientationSensor != null) {
mSensorManager.unregisterListener(mOrientationSensorEventListener);
}
if (mPressureSensor != null) {
mSensorManager.unregisterListener(mPressureSensorEventListener);
}
}
private void initResources() {
mDirection = 0.0f;
mTargetDirection = 0.0f;
mInterpolator = new AccelerateInterpolator();
mStopDrawing = true;
mChinease = TextUtils.equals(Locale.getDefault().getLanguage(), "zh");
mCompassView = findViewById(R.id.view_compass);
mPointer = (CompassView) findViewById(R.id.compass_pointer);
mAltitudeTextView = (TextView) findViewById(R.id.textview_altitude);
mPressureTextView = (TextView) findViewById(R.id.textview_pressure);
mDirectionLayout = (LinearLayout) findViewById(R.id.layout_direction);
mAngleLayout = (LinearLayout) findViewById(R.id.layout_angle);
mPointer.setImageResource(mChinease ? R.mipmap.compass_cn : R.mipmap.compass);
}
private void initServices() {
// sensor manager
mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mOrientationSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
mPressureSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_PRESSURE);
// location manager
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
}
private void updateDirection() {
LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
mDirectionLayout.removeAllViews();
mAngleLayout.removeAllViews();
ImageView east = null;
ImageView west = null;
ImageView south = null;
ImageView north = null;
float direction = normalizeDegree(mTargetDirection * -1.0f);
if (direction > 22.5f && direction < 157.5f) {
// east
east = new ImageView(this);
east.setImageResource(mChinease ? R.mipmap.e_cn : R.mipmap.e);
east.setLayoutParams(lp);
} else if (direction > 202.5f && direction < 337.5f) {
// west
west = new ImageView(this);
west.setImageResource(mChinease ? R.mipmap.w_cn : R.mipmap.w);
west.setLayoutParams(lp);
}
if (direction > 112.5f && direction < 247.5f) {
// south
south = new ImageView(this);
south.setImageResource(mChinease ? R.mipmap.s_cn : R.mipmap.s);
south.setLayoutParams(lp);
} else if (direction < 67.5 || direction > 292.5f) {
// north
north = new ImageView(this);
north.setImageResource(mChinease ? R.mipmap.n_cn : R.mipmap.n);
north.setLayoutParams(lp);
}
if (mChinease) {
// east/west should be before north/south
if (east != null) {
mDirectionLayout.addView(east);
}
if (west != null) {
mDirectionLayout.addView(west);
}
if (south != null) {
mDirectionLayout.addView(south);
}
if (north != null) {
mDirectionLayout.addView(north);
}
} else {
if (south != null) {
mDirectionLayout.addView(south);
}
if (north != null) {
mDirectionLayout.addView(north);
}
if (east != null) {
mDirectionLayout.addView(east);
}
if (west != null) {
mDirectionLayout.addView(west);
}
}
int direction2 = (int) direction;
boolean show = false;
if (direction2 >= 100) {
mAngleLayout.addView(getNumberImage(direction2 / 100));
direction2 %= 100;
show = true;
}
if (direction2 >= 10 || show) {
mAngleLayout.addView(getNumberImage(direction2 / 10));
direction2 %= 10;
}
mAngleLayout.addView(getNumberImage(direction2));
ImageView degreeImageView = new ImageView(this);
degreeImageView.setImageResource(R.mipmap.degree);
degreeImageView.setLayoutParams(lp);
mAngleLayout.addView(degreeImageView);
}
private ImageView getNumberImage(int number) {
ImageView image = new ImageView(this);
LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
switch (number) {
case 0:
image.setImageResource(R.mipmap.number_0);
break;
case 1:
image.setImageResource(R.mipmap.number_1);
break;
case 2:
image.setImageResource(R.mipmap.number_2);
break;
case 3:
image.setImageResource(R.mipmap.number_3);
break;
case 4:
image.setImageResource(R.mipmap.number_4);
break;
case 5:
image.setImageResource(R.mipmap.number_5);
break;
case 6:
image.setImageResource(R.mipmap.number_6);
break;
case 7:
image.setImageResource(R.mipmap.number_7);
break;
case 8:
image.setImageResource(R.mipmap.number_8);
break;
case 9:
image.setImageResource(R.mipmap.number_9);
break;
}
image.setLayoutParams(lp);
return image;
}
private SensorEventListener mOrientationSensorEventListener = new SensorEventListener() {
@Override
public void onSensorChanged(SensorEvent event) {
float direction = event.values[0] * -1.0f;
mTargetDirection = normalizeDegree(direction);
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
};
private SensorEventListener mPressureSensorEventListener = new SensorEventListener() {
@Override
public void onSensorChanged(SensorEvent event) {
mAltitudeTextView.setText(getString(R.string.altitude, (int) calculateAltitude(event.values[0])));
mPressureTextView.setText(getString(R.string.pressure, event.values[0] / 10));
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
};
private float calculateAltitude(float pressure) {
float sp = 1013.25f; //standard pressure
return (sp - pressure) * 100.0f / 12.7f;
}
private float normalizeDegree(float degree) {
return (degree 720) % 360;
}
}
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