Question

以下是我用于Android应用程序开发的3个java类。我想在AddActivity中添加学生数据（姓名和电话号码），点击＆＃34; Add＆＃34;后存储在MainActivity页面中。我已经研究了这个并尝试使用数组，但我对于如何将代码将AddActivity中键入的数据发送到MainActivity页面的逻辑非常困惑。任何人都可以给我一个如何解决这个问题的指导，如果你能用另一种方式向我展示我正在尝试的方式，我真的很感激。我希望在每个＆＃34; Add＆＃34;之后，将数据以ListView格式存储在MainActivity中。我点击了AddActivity页面。希望有人能够指导我这样做。谢谢。

MainActivity.java - https://jsfiddle.net/eb1fprnn/

public class MainActivity extends AppCompatActivity {
ListView listView;
Button addStudent;
ArrayList<Student> students = new ArrayList<Student>();
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    add();
}



public void add() {
    Student student;
    addStudent = (Button) findViewById(R.id.add);
    addStudent.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(MainActivity.this, AddActivity.class);
            startActivity(intent);
        }
    });
}
}

AddActivity.java - https://jsfiddle.net/40k5mas2/

public class AddActivity extends AppCompatActivity {
EditText name, phone;
Button add;
int FphoneNumber;
String Fname;
ArrayList<Student> students;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
students = (ArrayList<Student>) getIntent().getSerializableExtra("AddNewStudent");
setContentView(R.layout.activity_add);
edit();
addStudent();
}
public void edit() {
name = (EditText) findViewById(R.id.StudentName);
phone = (EditText) findViewById(R.id.phone);
final Button addStudent = (Button) findViewById(R.id.AddStudent);

name.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        addStudent.setEnabled(!name.getText().toString().trim().isEmpty());
        Fname = name.getText().toString();

        String phoneNumber = phone.getText().toString();
        FphoneNumber = Integer.parseInt(phoneNumber);
    }
    @Override
    public void afterTextChanged(Editable s) {
    }
});
}

public void addStudent() {

add = (Button) findViewById(R.id.AddStudent);

add.setOnClickListener(new View.OnClickListener() {
    @Override

    public void onClick(View v) {

        Intent intent = new Intent(AddActivity.this, MainActivity.class);
        intent.putExtra("studentName",name.getText().toString() );
        intent.putExtra("phoneNumber",phone.getText().toString());
        startActivity(intent);

        Student student = new Student(Fname, FphoneNumber);

        students.add(student);



    }
});
}

public void addStudent(){
add = (Button) findViewById(R.id.AddStudent);
add.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Intent intent = new Intent(AddActivity.this,Record.class);
        startActivity(intent);
    }
});
}

Student.java - https://jsfiddle.net/gy0g7b0s/

public class Student {

String mName;
int mPhoneNumber;


public Student (String name, int number){
mName = name;
mPhoneNumber = number;
};

public String getmName() {
return mName;
}

public String getmName(String newName) {
return (this.mName = newName);
}

public int getmPhoneNumber() {
return this.mPhoneNumber;
}

public int getmPhoneNumber(int newPhoneNumber) {
return (this.mPhoneNumber = newPhoneNumber);
}

@Override
public String toString() {
return String.format("%s\t%f",this.mName, this.mPhoneNumber);

[1]：[主要活动页面的图像] http://imgur.com/a/pMWt4

[2]：[添加活动页面的图片] http://imgur.com/a/8YvVc

Answer 1

您可以将它们存储为state.PassageReducer或创建AddActivity构造函数并获取函数。

public static variable

在另一项活动中

String student name; /*add value to this variable @onCreate or wherever in your AddActivity*/

public class AddActivity(/*here to pass data to addactivity*/){
//
}
public String getName(){
return this.name;
}

您可以使用此逻辑传递数据。

编辑但是如果你想用Intent传递数据，那么只需检查内容onCreate（）

AddActivity ac = new AddActivity();
String someName = ac.getName();

Answer 2

我能找到的最佳解决方案是，将数组列表声明为静态，如果类在同一个包中，您可以访问所需的位置。但是如果要存储这些值，请使用共享首选项。希望这可能有所帮助。

将数据添加到数组中以在另一个活动中列出

2 个答案: