Java 如果我在Android应用程序中使用许多活动，如何减少内存？

我目前正在开发一个简单的android应用程序，包含3个活动，每个活动都包含一些editText和两个按钮。 当我试着在我的真实设备上运行它时，我注意到它在执行过程中非常慢，占用了55MB的内存空间。 对于一个简单的应用程序来说，似乎没有太多的空间

我的一个Activitys.java：

package com.larig2.example;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.content.Intent;
import android.widget.RadioButton;
import android.widget.Spinner;
import android.widget.ArrayAdapter;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.EditText;
import android.widget.TextView;
import java.util.Calendar;
import android.support.design.widget.TextInputLayout;

public class content_signin_activity_admin extends AppCompatActivity {
    private ProgressDialog pDialog;

    JSONParser jsonParser = new JSONParser();
    EditText inputNomA;
    EditText inputPrenomA;
    EditText inputCINA;
    EditText inputJourA;
    Spinner inputMoisA;
    EditText inputAnneeA;
    Spinner inputAdresseA;
    EditText inputTelA;
    EditText inputMailA;
    EditText inputPwdA;
    RadioButton inputFemmeA;
    RadioButton inputHommeA;
    EditText inputPwdVefA;
    String nom;
    String prenom;
    String cin;
    String jour;
    String mois;
    String annee;
    String sexe;
    String adresse;
    String tel;
    String mail;
    String pwd;
    String pwdvef;
    String date;
    String tagres="";
    private static String url_create_product = "http://192.168.8.104/signup_admin.php";
    private static final String TAG_SUCCESS = "success";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_content_signin_activity_admin);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        final Intent contactus = new Intent(this, Contactez_nous.class);
        FloatingActionButton fab =  findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                startActivity(contactus);
            }
        });

        Spinner spinner =  findViewById(R.id.adresse);
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
                R.array.Tunisia_State, R.layout.spinnerthem1);
        adapter.setDropDownViewResource(R.layout.spinnerthem);
        spinner.setAdapter(adapter);

        Spinner spinnerMonths = findViewById(R.id.mois);layout
        ArrayAdapter<CharSequence> adapterMonths = ArrayAdapter.createFromResource(this,
                R.array.Mois_Date, R.layout.spinnerthem1);
        adapterMonths.setDropDownViewResource(R.layout.spinnerthem);
        spinnerMonths.setAdapter(adapterMonths);

        inputNomA =  findViewById(R.id.nom);
        inputPrenomA = findViewById(R.id.prenom);
        inputCINA = findViewById(R.id.CIN);
        inputJourA = findViewById(R.id.jour);
        inputMoisA = findViewById(R.id.mois);
        inputAnneeA = findViewById(R.id.annee);
        inputAdresseA = findViewById(R.id.adresse);
        inputTelA = findViewById(R.id.tel);
        inputMailA = findViewById(R.id.mail);
        inputPwdA = findViewById(R.id.pwd);
        inputFemmeA = findViewById(R.id.radioButtonFemale);
        inputHommeA = findViewById(R.id.radioButtonMale);
        inputPwdVefA = findViewById(R.id.pwdvef);
    }

    public String toMois(String mois){
        String nb="00";

        switch (mois){
            case "Janvier": nb="01";
                break;
            case "Fevrier": nb="02";
                break;
            case "Mars": nb="03";
                break;
            case "Avril": nb="04";
                break;
            case "Mai": nb="05";
                break;
            case "Juin": nb="06";
                break;
            case "Juillet": nb="07";
                break;
            case "Aoùt": nb="08";
                break;
            case "September": nb="09";
                break;
            case "October": nb="10";
                break;
            case "November": nb="11";
                break;
            case "December": nb="12";
                break;
        }

        return nb;
    }

    public boolean checkNom(String ent){
        char[] charsN = ent.toCharArray();
        if(charsN.length<3){
            return false;
        }else {
            for (char c : charsN) {
                if (!Character.isLetter(c)) {
                    return false;
                }
            }

        }
        return true;
    }
    public boolean checkPrenom(String ent){
        char[] charsN = ent.toCharArray();
        if(charsN.length<3){
            return false;
        }else {
            for (char c : charsN) {
                if (!Character.isLetter(c)) {
                    return false;
                }
            }

        }
        return true;
    }
    public boolean checkCINTel(String ent){
        char[] charsN = ent.toCharArray();
        if(!(charsN.length==8)){
            return false;
        }else {
            for (char c : charsN) {
                if (!Character.isDigit(c)) {
                    return false;
                }
            }

        }
        return true;
    }
    public boolean checkAnnee(String ent){
        char[] charsN = ent.toCharArray();

        if(!(charsN.length==4)){
            return false;
        }else {
            for (char c : charsN) {
                if (!Character.isDigit(c)) {
                    return false;
                }
            }

        }
        int var = Integer.parseInt(ent);
        if ( !(var <= (Calendar.getInstance().get(Calendar.YEAR) - 18)) && (var > (Calendar.getInstance().get(Calendar.YEAR) - 100))) {
            return false;
        }
        return true;
    }
    public boolean checkJour(String ent, int a){
        char[] charsN = ent.toCharArray();

        if(!(charsN.length==2 || charsN.length==1)){
            return false;
        }else {
            for (char c : charsN) {
                if (!Character.isDigit(c)) {
                    return false;
                }
            }

        }
        int var= Integer.parseInt(ent);
        return ((var <= a) && (var >= 1)) ;
    }

    public boolean chekDate(String j, String m, String a){
        if (checkAnnee(a)) {
            if (m == "01" || m == "03" || m == "05" || m == "07" || m == "08" || m == "10" || m == "12") {
                if (checkJour(j, 31)) {
                    return true;
                }
            } else if (m == "04" || m == "06" || m == "9" || m == "11") {
                if (checkJour(j, 30)) {
                    return true;
                }
            } else {
                if ((Integer.parseInt(a) % 4 == 0)) {
                    if (checkJour(j, 29)) {
                        return true;
                    }
                } else {
                    if (checkJour(j, 28)) {
                        return true;
                    }
                }
            }
        }
        return  false;
    }
    public boolean checkGenre(String ent){
        if (ent=="none") {
            return false;
        }
        return true;
    }
    public boolean isValidEmailAddress(String email) {
        String ePattern = "^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\])|(([a-zA-Z\\-0-9]+\\.)+[a-zA-Z]{2,}))$";
        java.util.regex.Pattern p = java.util.regex.Pattern.compile(ePattern);
        java.util.regex.Matcher m = p.matcher(email);
        return m.matches();
    }
    public boolean isValidPassword(String ent){
        char[] charsN = ent.toCharArray();
        if(!(charsN.length<6)){
            return true;
        }
        return false;
    }
    public void signupClickA(View view) {
        TextInputLayout til = findViewById(R.id.text_input_layout);
        til.setError("You need to enter a name");
        cin = inputCINA.getText().toString();
        nom = inputNomA.getText().toString();
        prenom = inputPrenomA.getText().toString();
        jour = inputJourA.getText().toString();
        mois = toMois(inputMoisA.getSelectedItem().toString());
        annee = inputAnneeA.getText().toString();
        adresse = inputAdresseA.getSelectedItem().toString();
        tel = inputTelA.getText().toString();
        mail = inputMailA.getText().toString();
        pwd = inputPwdA.getText().toString();
        pwdvef = inputPwdVefA.getText().toString();
        date= annee+"-"+mois+"-"+jour;
        sexe= "none";
        if (inputFemmeA.isChecked()) {
            sexe="femme";
        }
        if (inputHommeA.isChecked()) {
            sexe= "homme";
        }


        if(checkNom(nom)){
            if (checkPrenom(prenom)){
                if (checkCINTel(cin)) {
                    if(chekDate(jour,mois,annee)) {
                        if(checkGenre(sexe)) {
                            if (checkCINTel(tel)) {
                                if (isValidEmailAddress(mail)) {
                                    if (isValidPassword(pwd)) {
                                        if(pwdvef.equals(pwd)) {

                                            new CreateNewClient().execute();
                                        }else{
                                            Snackbar.make(view, "La verification de mot de passe échoué", Snackbar.LENGTH_LONG)
                                                    .setAction("Action", null).show();
                                        }
                                    }else{
                                        Snackbar.make(view, "Le mot de passe doit être au minimum 6 lettres.", Snackbar.LENGTH_LONG)
                                                .setAction("Action", null).show();
                                    }
                                }else{
                                    Snackbar.make(view, "Verifier votre Email", Snackbar.LENGTH_LONG)
                                            .setAction("Action", null).show();
                                }
                            }else{
                                Snackbar.make(view, "Verifier votre numéro de telephone", Snackbar.LENGTH_LONG)
                                        .setAction("Action", null).show();
                            }
                        }else{
                            Snackbar.make(view, "Verifier votre genre (Femme ou Homme)", Snackbar.LENGTH_LONG)
                                    .setAction("Action", null).show();
                        }
                    }else {
                        Snackbar.make(view, "Verifier la date de naissance", Snackbar.LENGTH_LONG)
                                .setAction("Action", null).show();
                    }
                }else {
                    Snackbar.make(view, "Verifier votre Carte d'identité! (8 chiffres)", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                }
            }else {
                Snackbar.make(view, "Verifier votre Prenom! (Minimum 3 lettres)", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        }else {
            Snackbar.make(view, "Verifier votre Nom! (Minimum 3 lettres)", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    }
    class CreateNewClient extends AsyncTask<String, String, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(content_signin_activity_admin.this);
            pDialog.setMessage("Ex...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
        protected String doInBackground(String... args) {
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("nomC", nom));
            params.add(new BasicNameValuePair("prenomC", prenom));
            params.add(new BasicNameValuePair("CIN", cin));
            params.add(new BasicNameValuePair("date",date ));
            params.add(new BasicNameValuePair("sexe", sexe));
            params.add(new BasicNameValuePair("adresse", adresse));
            params.add(new BasicNameValuePair("tel", tel));
            params.add(new BasicNameValuePair("mail", mail));
            params.add(new BasicNameValuePair("psw", pwd));
            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params);
            Log.d("Create Response", json.toString());
            try {
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // successfully created product
                    Intent i = new Intent(getApplicationContext(), ClientSpace.class);
                    startActivity(i);
                    finish();
                }else if(success == 2){
                    tagres="2";
                }else if(success == 3){
                    tagres="3";
                }
            } catch (JSONException e) {
                Intent i = new Intent(getApplicationContext(), MainActivity.class);
                startActivity(i);
            }

            return null;
        }
        protected void onPostExecute(String file_url) {
            pDialog.dismiss();
            if(tagres == "2"){
                TextView txt=(TextView) findViewById(R.id.CINError);
                Snackbar.make(txt, "Un compte déja créer par cette carte d'identité", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }else if(tagres == "3"){
                TextView txt=(TextView) findViewById(R.id.CINError);
                Snackbar.make(txt, "Un compte déja créer par cette Email", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        }
    }
}

布局：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.larig2.karhabti.content_signin_activity_admin"
    tools:showIn="@layout/activity_content_signin_activity_admin"
    android:background="#225D9F"
    >
    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingBottom="16dp"
        android:paddingLeft="16dp"
        android:paddingRight="16dp"
        android:paddingTop="16dp"
        android:id="@+id/scrollView2"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" >
        <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <ImageView
                android:contentDescription="@string/app_name"
                android:src="@drawable/main_logo"
                android:layout_width="match_parent"
                android:layout_height="150dp"
                android:id="@+id/imageView2"
                android:layout_gravity="center_horizontal" />

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textPersonName"
                android:hint="@string/prompt_firstname"
                android:maxLength="15"
                android:ems="10"
                android:id="@+id/nom"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3" />

            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textPersonName"
                android:hint="@string/prompt_lastname"
                android:maxLength="15"
                android:ems="10"
                android:id="@+id/prenom"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3" />

            <android.support.design.widget.TextInputLayout
                android:id="@+id/text_input_layout"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:errorEnabled="true"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3">
            <EditText
                android:enabled="true"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="number"
                android:hint="@string/prompt_cin"
                android:maxLength="8"
                android:ems="10"
                android:id="@+id/CIN"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3"
                />
            </android.support.design.widget.TextInputLayout>

            <LinearLayout
                android:orientation="horizontal"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:weightSum="3"
                android:layout_marginTop="29dp">

                <EditText
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:inputType="number"
                    android:ems="10"
                    android:id="@+id/jour"
                    android:maxLength="2"
                    android:layout_weight="1"
                    android:textColor="#ffffff"
                    android:backgroundTint="#5EB0E2"
                    android:textColorHint="#367FC3"
                    android:hint="@string/prompt_day"/>

                <LinearLayout
                    android:orientation="vertical"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:textAppearance="?android:attr/textAppearanceMedium"
                        android:text="@string/prompt_month"
                        android:id="@+id/textView3"
                        android:layout_gravity="center_horizontal"
                        android:textColor="#367FC3"/>

                    <Spinner
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:id="@+id/mois"
                        android:popupBackground="#595959"
                        />
                </LinearLayout>

                <EditText
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:inputType="number"
                    android:ems="10"
                    android:id="@+id/annee"
                    android:maxLength="4"
                    android:layout_weight="1"
                    android:textColor="#ffffff"
                    android:backgroundTint="#5EB0E2"
                    android:textColorHint="#367FC3"
                    android:hint="@string/prompt_year"/>
            </LinearLayout>
            <RadioGroup
                android:orientation="horizontal"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:id="@+id/sexe">

                <RadioButton
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/prompt_female"
                    android:id="@+id/radioButtonFemale"
                    android:layout_marginStart="25dp"
                    android:layout_marginTop="31dp"
                    android:checked="false"
                    android:textColor="#367FC3"
                    android:buttonTint="#5EB0E2"
                    />

                <RadioButton
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/prompt_male"
                    android:id="@+id/radioButtonMale"
                    android:layout_marginStart="45dp"
                    android:layout_marginTop="31dp"
                    android:checked="false"
                    android:textColor="#367FC3"
                    android:buttonTint="#5EB0E2"
                    />
            </RadioGroup>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:text="@string/prompt_Address"
                android:id="@+id/textView2"
                android:layout_gravity="center_horizontal"
                android:textColor="#367FC3"
                android:layout_marginTop="20dp"
                />

            <Spinner
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/adresse"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:focusable="false"
                android:spinnerMode="dropdown"
                android:popupBackground="#595959"
                android:backgroundTint="#5EB0E2"
                />

            <EditText
                android:enabled="true"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="phone"
                android:maxLength="8"
                android:hint="@string/prompt_tel"
                android:ems="10"
                android:id="@+id/tel"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3"/>
            <EditText
                android:enabled="true"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textEmailAddress"
                android:hint="@string/prompt_email"
                android:maxLength="30"
                android:ems="10"
                android:id="@+id/mail"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3"/>
            <EditText
                android:enabled="true"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textPassword"
                android:hint="@string/prompt_password"
                android:maxLength="15"
                android:ems="10"
                android:id="@+id/pwd"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3"/>
            <EditText
                android:enabled="true"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textPassword"
                android:hint="@string/prompt_repassword"
                android:maxLength="15"
                android:ems="10"
                android:id="@+id/pwdvef"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3"/>
            <EditText
                android:enabled="true"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="text"
                android:hint="@string/prompt_grad"
                android:ems="10"
                android:id="@+id/editText9"
                android:layout_gravity="center_horizontal"
                android:textColor="#ffffff"
                android:backgroundTint="#5EB0E2"
                android:textColorHint="#367FC3"/>
            <android.support.v7.widget.AppCompatButton
                android:id="@+id/btn_login"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="24dp"
                android:layout_marginBottom="24dp"
                android:padding="12dp"
                android:text="@string/action_sign_in"
                android:background="#ffffff"
                android:textColor="#2F86C9"
                android:onClick="signupClickA"
                />
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/CINError"
                android:visibility="invisible"/>
        </LinearLayout>
    </ScrollView>
</RelativeLayout>

---

它可以通过内存分析器分析应用程序的内存分布来解决。转到视图>工具窗口>Android探查器