First impl

app/build.gradle

@@ -16,13 +16,19 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 }
 
 dependencies {
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation fileTree(include: ['*.jar'], dir: 'libs')
     implementation 'com.android.support:appcompat-v7:28.0.0'
     implementation 'com.android.support.constraint:constraint-layout:1.1.3'
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+    implementation 'com.android.support:recyclerview-v7:28.0.0'
+    implementation 'de.hdodenhof:circleimageview:3.0.0'
 }

app/src/main/java/ru/ok/technopolis/students/MainActivity.java

@@ -1,14 +1,147 @@
 package ru.ok.technopolis.students;
 
-import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
+import android.support.v7.app.AppCompatActivity;
+import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.text.TextUtils;
+import android.widget.Button;
+import android.widget.CheckBox;
+import android.widget.EditText;
+import android.widget.Toast;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import de.hdodenhof.circleimageview.CircleImageView;
 
 public class MainActivity extends AppCompatActivity {
 
+    private List<Student> students;
+    private StudentAdapter studentAdapter;
+    private int pics[];
+    private Student currentStudent;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        students = new ArrayList<>();
+        pics = new int[6];
+        currentStudent = null;
         setContentView(R.layout.activity_main);
+        setupRecyclerView();
+        setupAddButton();
+        setupSaveButton();
+        setupDeleteButton();
+        setupPics();
+    }
+
+    private void setupRecyclerView() {
+        RecyclerView recyclerView = findViewById(R.id.activity_main__rv_students);
+        studentAdapter = new StudentAdapter(students, this::onStudentClick);
+        recyclerView.setAdapter(studentAdapter);
+        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
+        recyclerView.setLayoutManager(linearLayoutManager);
+    }
+
+    private void setupPics() {
+        pics[0] = R.drawable.male_1;
+        pics[1] = R.drawable.male_2;
+        pics[2] = R.drawable.male_3;
+        pics[3] = R.drawable.female_1;
+        pics[4] = R.drawable.female_2;
+        pics[5] = R.drawable.female_3;
+    }
+
+    private void setupAddButton() {
+        Button button = findViewById(R.id.activity_main__btn_add);
+        button.setOnClickListener(v -> onAddClick());
+    }
+
+    private void onAddClick() {
+        setupEdit("", "", false, 0);
+        currentStudent = new Student("", "", false, 0);
+        studentAdapter.resetSelectionPos();
+        studentAdapter.notifyDataSetChanged();
+    }
+
+    private void setupEdit(String name, String familyName, Boolean isMale, int pic) {
+        EditText nameEdit = findViewById(R.id.names_layout__edit_name);
+        EditText familyNameEdit = findViewById(R.id.names_layout__edit_fname);
+        CheckBox male = findViewById(R.id.sex_layout__checkbox);
+        CircleImageView pics = findViewById(R.id.data_layout__edit_img);
+        nameEdit.setText(name);
+        familyNameEdit.setText(familyName);
+        male.setChecked(isMale);
+        pics.setImageResource(pic);
+    }
+
+    private void setupSaveButton() {
+        Button button = findViewById(R.id.cl_edit__save);
+        button.setOnClickListener(v -> onSaveClick());
+    }
+
+    private void setupDeleteButton() {
+        Button button = findViewById(R.id.cl_edit__delete);
+        button.setOnClickListener(v -> onDeleteClick());
+    }
+
+    private void onDeleteClick() {
+        if (currentStudent == null) {
+            Toast.makeText(this, R.string.empty_student, Toast.LENGTH_SHORT).show();
+        } else {
+            students.remove(currentStudent);
+            currentStudent = null;
+            studentAdapter.resetSelectionPos();
+            studentAdapter.notifyDataSetChanged();
+            setupEdit("", "", Boolean.FALSE, 0);
+        }
+    }
+
+    private void onSaveClick() {
+        EditText name = findViewById(R.id.names_layout__edit_name);
+        EditText familyName = findViewById(R.id.names_layout__edit_fname);
+        CheckBox male = findViewById(R.id.sex_layout__checkbox);
+        CircleImageView pic = findViewById(R.id.data_layout__edit_img);
+        int picId;
+        if ((name.getText() != null) && (familyName.getText() != null)) {
+            if (TextUtils.isEmpty(name.getText().toString().trim())
+                    || TextUtils.isEmpty(familyName.getText().toString().trim())) {
+                Toast.makeText(this, R.string.wrong_enter, Toast.LENGTH_SHORT).show();
+            } else {
+                if (currentStudent == null || currentStudent.getFirstName().equals("")) {
+                    students.add(currentStudent = new Student(name.getText().toString().trim(),
+                            familyName.getText().toString().trim(),
+                            male.isChecked(),
+                            picId = getRandomPick(male.isChecked())));
+                    pic.setImageResource(picId);
+                    studentAdapter.resetSelectionPos();
+                    studentAdapter.notifyDataSetChanged();
+                } else {
+                    currentStudent.setFirstName(name.getText().toString().trim());
+                    currentStudent.setSecondName(familyName.getText().toString().trim());
+                    if (currentStudent.isMaleGender() != male.isChecked()) {
+                        currentStudent.setPhoto(picId = getRandomPick(male.isChecked()));
+                        currentStudent.setMaleGender(male.isChecked());
+                        pic.setImageResource(picId);
+                    }
+                    studentAdapter.notifyDataSetChanged();
+                }
+            }
+        }
+
+    }
+
+    private int getRandomPick(Boolean isMale) {
+        Random random = new Random();
+        int maleRandom = isMale ? 0 : 3;
+        return pics[maleRandom + random.nextInt(3)];
+    }
+
+    private void onStudentClick(Student student) {
+        setupEdit(student.getFirstName(), student.getSecondName(), student.isMaleGender(), student.getPhoto());
+        currentStudent = student;
     }
 
 }

app/src/main/java/ru/ok/technopolis/students/StudentAdapter.java

@@ -0,0 +1,93 @@
+package ru.ok.technopolis.students;
+
+import android.graphics.Color;
+import android.support.annotation.NonNull;
+import android.support.v7.widget.RecyclerView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import java.util.List;
+
+import de.hdodenhof.circleimageview.CircleImageView;
+
+public class StudentAdapter extends RecyclerView.Adapter<StudentAdapter.StudentViewHolder> {
+
+    private final List<Student> students;
+    private final Listener onStudentClickListener;
+    private static final int SELECTED_COLOR = Color.parseColor("#F0F0F0");
+    private int selectedPosition;
+
+    public StudentAdapter(List<Student> students, Listener onStudentClickListener) {
+        this.students = students;
+        this.onStudentClickListener = onStudentClickListener;
+    }
+
+    @NonNull
+    @Override
+    public StudentViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
+        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.student_item, viewGroup, false);
+        view.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                onStudentClickListener.onStudentClick((Student) v.getTag());
+                selectedPosition = ((RecyclerView.LayoutParams) v.getLayoutParams()).getViewLayoutPosition();
+                notifyDataSetChanged();
+            }
+        });
+        return new StudentViewHolder(view);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull StudentViewHolder holder, final int position) {
+        Student student = students.get(position);
+        holder.bind(student);
+        holder.itemView.setTag(student);
+        selectionSetup(holder);
+    }
+
+    @Override
+    public int getItemCount() {
+        return students.size();
+    }
+
+    private void selectionSetup(StudentViewHolder holder) {
+        if (selectedPosition == holder.getLayoutPosition()) {
+            holder.itemView.setBackgroundColor(SELECTED_COLOR);
+        } else {
+            holder.itemView.setBackgroundColor(Color.TRANSPARENT);
+        }
+    }
+
+    public void resetSelectionPos() {
+        selectedPosition = RecyclerView.NO_POSITION;
+    }
+
+    interface Listener {
+
+        void onStudentClick(Student student);
+
+    }
+
+    static final class StudentViewHolder extends RecyclerView.ViewHolder {
+
+        private final CircleImageView profileImage;
+        private final TextView nameTextView;
+        private final TextView familyNameTextView;
+
+        public StudentViewHolder(@NonNull View itemView) {
+            super(itemView);
+            profileImage = itemView.findViewById(R.id.student_item__img);
+            nameTextView = itemView.findViewById(R.id.student_item__name);
+            familyNameTextView = itemView.findViewById(R.id.student_item__fname);
+        }
+
+        private void bind(@NonNull Student student) {
+            nameTextView.setText(student.getFirstName());
+            familyNameTextView.setText(student.getSecondName());
+            profileImage.setImageResource(student.getPhoto());
+        }
+
+    }
+}