我的问题是，我的计步器只在打开应用程序时计算步数。
我一离开应用程序，它就停止计数。
安卓应用程序的目标是，只要应用程序在前台或后台，就可以计算步数。
当应用程序处于后台时，我必须做些什么才能使其工作？
package com.example.mysmartnutrition;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import java.util.Date;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.json.JSONException;
import org.json.JSONObject;
public class MainActivity extends AppCompatActivity implements SensorEventListener {
// Objects from the activity_main.xml file
private FloatingActionButton addButton;
private Button addBreakfast;
private Button addLunch;
private Button addDinner;
private TextView tvStepCounter;
private SensorManager sensorManager;
private Sensor stepCounterSensor;
private boolean isStepCounterPresent;
private int stepCount = 0;
private int stepsOfToday = 0;
public int dayStep = 0;
/* private List<Integer> savedStepsList = new List<Integer>() {
@Override
public int size() {
return 0;
}
@Override
public boolean isEmpty() {
return false;
}
@Override
public boolean contains(@Nullable Object o) {
return false;
}
@NonNull
@Override
public Iterator<Integer> iterator() {
return null;
}
@NonNull
@Override
public Object[] toArray() {
return new Object[0];
}
@NonNull
@Override
public <T> T[] toArray(@NonNull T[] a) {
return null;
}
@Override
public boolean add(Integer integer) {
return false;
}
@Override
public boolean remove(@Nullable Object o) {
return false;
}
@Override
public boolean containsAll(@NonNull Collection<?> c) {
return false;
}
@Override
public boolean addAll(@NonNull Collection<? extends Integer> c) {
return false;
}
@Override
public boolean addAll(int index, @NonNull Collection<? extends Integer> c) {
return false;
}
@Override
public boolean removeAll(@NonNull Collection<?> c) {
return false;
}
@Override
public boolean retainAll(@NonNull Collection<?> c) {
return false;
}
@Override
public void clear() {
}
@Override
public Integer get(int index) {
return null;
}
@Override
public Integer set(int index, Integer element) {
return null;
}
@Override
public void add(int index, Integer element) {
}
@Override
public Integer remove(int index) {
return null;
}
@Override
public int indexOf(@Nullable Object o) {
return 0;
}
@Override
public int lastIndexOf(@Nullable Object o) {
return 0;
}
@NonNull
@Override
public ListIterator<Integer> listIterator() {
return null;
}
@NonNull
@Override
public ListIterator<Integer> listIterator(int index) {
return null;
}
@NonNull
@Override
public List<Integer> subList(int fromIndex, int toIndex) {
return null;
}
}; */
public String savedDate;
public String notSavedDate;
public SharedPreferences sharedPreferences = new SharedPreferences() {
@Override
public Map<String, ?> getAll() {
return null;
}
@Nullable
@Override
public String getString(String key, @Nullable String defValue) {
return null;
}
@Nullable
@Override
public Set<String> getStringSet(String key, @Nullable Set<String> defValues) {
return null;
}
@Override
public int getInt(String key, int defValue) {
return 0;
}
@Override
public long getLong(String key, long defValue) {
return 0;
}
@Override
public float getFloat(String key, float defValue) {
return 0;
}
@Override
public boolean getBoolean(String key, boolean defValue) {
return false;
}
@Override
public boolean contains(String key) {
return false;
}
@Override
public Editor edit() {
return null;
}
@Override
public void registerOnSharedPreferenceChangeListener(OnSharedPreferenceChangeListener listener) {
}
@Override
public void unregisterOnSharedPreferenceChangeListener(OnSharedPreferenceChangeListener listener) {
}
};
public SharedPreferences.Editor editor = new SharedPreferences.Editor() {
@Override
public SharedPreferences.Editor putString(String key, @Nullable String value) {
return null;
}
@Override
public SharedPreferences.Editor putStringSet(String key, @Nullable Set<String> values) {
return null;
}
@Override
public SharedPreferences.Editor putInt(String key, int value) {
return null;
}
@Override
public SharedPreferences.Editor putLong(String key, long value) {
return null;
}
@Override
public SharedPreferences.Editor putFloat(String key, float value) {
return null;
}
@Override
public SharedPreferences.Editor putBoolean(String key, boolean value) {
return null;
}
@Override
public SharedPreferences.Editor remove(String key) {
return null;
}
@Override
public SharedPreferences.Editor clear() {
return null;
}
@Override
public boolean commit() {
return false;
}
@Override
public void apply() {
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(ContextCompat.checkSelfPermission(this,
Manifest.permission.ACTIVITY_RECOGNITION) == PackageManager.PERMISSION_DENIED){ //ask for permission
requestPermissions(new String[]{Manifest.permission.ACTIVITY_RECOGNITION}, 0);
}
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
addButton = findViewById(R.id.fab);
addBreakfast = findViewById(R.id.add_product_breakfast);
addLunch = findViewById(R.id.add_product_lunch);
addDinner = findViewById(R.id.add_product_dinner);
tvStepCounter = findViewById(R.id.stepCounter);
addButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, AddProduct.class);
startActivity(intent);
}
});
addBreakfast.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, AddProduct.class);
startActivity(intent);
}
});
addLunch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, AddProduct.class);
startActivity(intent);
}
});
addDinner.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, AddProduct.class);
startActivity(intent);
}
});
if(sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER) != null) {
stepCounterSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
isStepCounterPresent = true;
} else {
tvStepCounter.setText("Step counter sensor is not present");
isStepCounterPresent = false;
}
savedDate = String.valueOf(java.time.LocalDate.now());
SQLiteDatabase database = openOrCreateDatabase("mysmartnutrition.db", MODE_PRIVATE, null);
database.execSQL("create table if not exists steps(date text, stepCounter integer, kcalBurned integer)");
dayStep = 0;
getData();
//Toast.makeText(getApplicationContext(), " " + savedDate + " ", Toast.LENGTH_LONG).show();
}
public void pushStepsToDB(int dayStep){
SQLiteDatabase database = openOrCreateDatabase("mysmartnutrition.db", MODE_PRIVATE, null);
database.execSQL("create table if not exists steps(date text, stepCounter integer, kcalBurned integer)");
String CONTACTS_TABLE_NAME = "steps";
database.execSQL("UPDATE "+CONTACTS_TABLE_NAME+" SET stepCounter = "+"'"+ dayStep +"' "+ "WHERE date = "+"'"+savedDate+"'");
database.close();
//Toast.makeText(getApplicationContext(), " " + "succesful" + " ", Toast.LENGTH_SHORT).show();
}
public void getData(){
savedDate = String.valueOf(java.time.LocalDate.now());
if(checkIsEntryAlreadyInDB() == true){
SQLiteDatabase database = openOrCreateDatabase("mysmartnutrition.db", MODE_PRIVATE, null);
Cursor cursor = database.rawQuery("select * from steps where date = '" + savedDate + "'", null);
cursor.moveToFirst();
String date = cursor.getString(0);
dayStep = Integer.valueOf(cursor.getString(1));
String kcal = cursor.getString(2);
cursor.close();
database.close();
}
else{
SQLiteDatabase database = openOrCreateDatabase("mysmartnutrition.db", MODE_PRIVATE, null);
database.execSQL("create table if not exists steps(date text, stepCounter integer, kcalBurned integer)");
database.execSQL("insert into steps values('" + savedDate + "', '0', '0')");
database.close();
Toast.makeText(getApplicationContext(), " " + "Entry not found but generated" + " ", Toast.LENGTH_SHORT).show();
}
//Toast.makeText(getApplicationContext(), " " + dayStep + " step" + " ", Toast.LENGTH_SHORT).show();
}
public boolean checkIsEntryAlreadyInDB(){
SQLiteDatabase database = openOrCreateDatabase("mysmartnutrition.db", MODE_PRIVATE, null);
Cursor cursor = database.rawQuery("select * from steps where date = '" + savedDate + "'", null);
if(cursor.getCount() <= 0){
cursor.close();
return false;
}
cursor.close();
return true;
}
@Override
public void onSensorChanged(SensorEvent event) {
if(event.sensor == stepCounterSensor) {
stepCount = (int) event.values[0];
savedDate = String.valueOf(java.time.LocalDate.now());
SQLiteDatabase database = openOrCreateDatabase("mysmartnutrition.db", MODE_PRIVATE, null);
database.execSQL("create table if not exists steps(date text, stepCounter integer, kcalBurned integer)");
dayStep = 0;
getData();
dayStep ++;
pushStepsToDB(dayStep);
tvStepCounter.setText(String.valueOf(dayStep));
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
@Override
protected void onResume() {
super.onResume();
if(sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER) != null) {
sensorManager.registerListener(this, stepCounterSensor, SensorManager.SENSOR_DELAY_UI);
}
}
@Override
protected void onPause() {
super.onPause();
if(sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER) != null) {
sensorManager.unregisterListener(this, stepCounterSensor);
}
}
}
它停止的原因很简单，您可以在onPause方法中停止侦听。如果您想在后台计算步骤数，则需要实现一个服务。但是，看到代码的其余部分，也许可以先做一些更简单的事情。随着安卓优化电池使用，你将有很多事情要做，让你的服务在后台运行。
不确定您要做什么，但您正在定义自己的SharedPreferences实现。通常你会称之为：
final SharedPreferences prefs = context.getSharedPreferences("filename", MODE_PRIVATE);