常见的Android数据传递方法汇总
一、Intent与Bundle
1、Activty与Activity
1.1、传递简单数据
（1） 传单个值（以String类型为例）
- 发送数据
Intent intent = new Intent(A.this, B.class);
intent.putExtra("key", value);
startActivity(intent);
- 接收数据
// 获取数据的方法需要根据传递的数据类型而定
Intent reIntent = getIntent();
String tempStr = reIntent.getStringExtra("key");
（2）传多个值
- 发送数据
Intent intent = new Intent(A.this, B.class);
Bundle bd = new Bundle();
bd.putString("name", "张三");
bd.putInt("age", 23);
intent.putExtras(bd);
startActivity(intent);
- 接收数据
Intent reIntent = getIntent();
Bundle reBd = reIntent.getExtras();
String name = reBd.getString("name");
int age = reBd.getInt("age");
1.2、传递复杂数据
- 数组
（1）纯Intent
- 传递数据
Intent intent = new Intent(A.this, B.class);
intent.putExtra("arrName", new String[]{"张三", "李四", "王五"});
startActivity(intent);
- 接收数据
Intent reIntent = getIntent();
reIntent.getStringArrayExtra("arrName");
（2）Intent和Bundle
- 传递数据
Intent intent = new Intent(A.this, B.class);
Bundle bd = new Bundle();
bd.putStringArray("arrName", new String[]{"张三", "李四", "王五"});
intent.putExtras(bd);
startActivity(intent);
- 接收数据
Intent reIntent = getIntent();
Bundle reBd = reIntent.getExtras();
reBd.getStringArray("arrName");
- 集合
（1）List<基本数据类型或String、Integer>
单用Intent或Intent与Bundle结合都可以
- 发送数据
ArrayList<String> strList = new ArrayList<>();
stringList.add("张三");
stringList.add("李四");
Intent listIntent = new Intent(A.this, B.claaa);
listIntent.putStringArrayListExtra("strList", strList);
startActivity(listIntent);
- 接收数据
Intent reIntent = getIntent();
reIntent.getStringArrayListExtra("strList");
（2）List<自定义对象>
- 首先自定义对象要实现Serializable接口
import java.io.Serializable;
public class Student implements Serializable {
private String name;
private int age;
private String sex;
private String grade;
private String school;
public Student(String name, int age, String sex, String grade, String school) {
this.name = name;
this.age = age;
this.sex = sex;
this.grade = grade;
this.school = school;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
public String getSchool() {
return school;
}
public void setSchool(String school) {
this.school = school;
}
}
- 发送数据
Intent intent = new Intent(A.this, B.class);
List<Student> studentList = new ArrayList<>();
studentList.add(new Student("张三", 25, "男", "大三", "广州大学"));
studentList.add(new Student("李四", 24, "男", "大二", "贵州大学"));
studentList.add(new Student("李红", 27, "男", "大四", "清华大学"));
studentList.add(new Student("王五", 23, "男", "大一", "北京大学"));
intent.putExtra("studentList", (Serializable) studentList);
startActivity(intent);
- 接收数据
Intent reIntent = getIntent();
List<Student> reStudentList = (List<Student>) reIntent.getSerializableExtra("studentList");
- 对象
（1）使用Serializable序列化对象；
- 序列化对象
import java.io.Serializable;
/**
* 学生
*/
public class Student implements Serializable {
private String name;
private int age;
private String sex;
private String grade;
private String school;
public Student(String name, int age, String sex, String grade, String school) {
this.name = name;
this.age = age;
this.sex = sex;
this.grade = grade;
this.school = school;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
public String getSchool() {
return school;
}
public void setSchool(String school) {
this.school = school;
}
}
- 发送数据
Intent intent = new Intent(A.this, B.class);
Student stu1 = new Student("张三", 25, "男", "大三", "广州大学");
intent.putExtra("stu1", stu1);
startActivity(intent);
- 接收数据
Intent reIntent = getIntent();
Student stu1 = (Student) reIntent.getSerializableExtra("stu1");
（2）使用Parcelable序列化对象；
- 序列化对象
import android.os.Parcel;
import android.os.Parcelable;
/**
* 课程
*/
public class Course implements Parcelable {
private String courseName;
private String courseType;
public Course() {
}
public Course(String courseName, String courseType) {
this.courseName = courseName;
this.courseType = courseType;
}
public String getCourseName() {
return courseName;
}
public void setCourseName(String courseName) {
this.courseName = courseName;
}
public String getCourseType() {
return courseType;
}
public void setCourseType(String courseType) {
this.courseType = courseType;
}
@Override
public int describeContents() {
// 内容描述，返回0就可以
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
// 将Course对象转化成Parcel，
// dest是目标Parcel，
// flags标志object是如何被写的。
// 0或者PARCELABLE_WRITE_RETURN_VALUE
dest.writeString(courseName);
dest.writeString(courseType);
}
public static final Creator<Course> CREATOR = new Creator<Course>() {
@Override
public Course createFromParcel(Parcel in) {
// 将Parcel映射成Course对象
Course mCourse = new Course();
// 同种数据类型，顺序为先进先出
mCourse.courseName = in.readString();
mCourse.courseType = in.readString();
return mCourse;
}
@Override
public Course[] newArray(int size) {
return new Course[size];
}
};
}
- 发送数据
Intent intent = new Intent(A.this, B.class);
Course course = new Course("语文", "文科");
intent.putExtra("course", course);
startActivity(intent);
- 接收数据
Intent reIntent = getIntent();
Course mCourse = reIntent.getParcelableExtra("course");
（3）使用Gson将对象转化为Json格式再传递。
- 导入依赖包
//添加Gson依赖
implementation 'com.google.code.gson:gson:2.8.8'
- 定义对象
public class Book {
private String bookName;
private String bookAuthor;
public Book(String bookName, String bookAuthor) {
this.bookName = bookName;
this.bookAuthor = bookAuthor;
}
public String getBookName() {
return bookName;
}
public void setBookName(String bookName) {
this.bookName = bookName;
}
public String getBookAuthor() {
return bookAuthor;
}
public void setBookAuthor(String bookAuthor) {
this.bookAuthor = bookAuthor;
}
}
- 发送数据
Intent intent = new Intent(A.this, B.class);
Book book = new Book("西游记", "吴承恩");
intent.putExtra("book", new Gson().toJson(book));
startActivity(intent);
- 接收数据
Intent reIntent = getIntent();
String bookJson = reIntent.getStringExtra("book");
Book mBook = new Gson().fromJson(bookJson, Book.class);
2、Activity与Fragment
2.1、Activity传递数据给Fragment
1、通过构造函数传递
- step1：在RightFragment.java中重载构造函数
private String mData;
public RightFragment(String data) {
mData = data;
}
- step2：在MainActivityFour.java中创建Fragment实例的同时，通过构造函数将数据传递过去
RightFragment rightFragment = new RightFragment("GetDataFromMainTwo");
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fl_right, rightFragment, "rightFragment");
transaction.commit();
2、通过setArguments()传递
- step1：在MainActivityFour.java初始化Fragment时，使用setArgments传递数据
RightFragment rightFragment = new RightFragment();
Bundle bundle = new Bundle();
bundle.putString("main_data", "GetDataFromMainThree");
rightFragment.setArguments(bundle);
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fl_right, rightFragment, "rightFragment");
transaction.commit();
- step2：在RightFragment.java中获取数据
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (isAdded()) {
String getData = "";
Bundle bundle = getArguments();
if (bundle != null)
getData = getArguments().getString("main_data");
tvShowContent.setText(getData);
}
}
3、Fragment中定义方法再调用
- step1：在RightFragment.java中定义一个接收数据的方法
public void setData(String dataMsg) {
tvShowContent.setText(dataMsg);
}
- step2：在MianActivityFour.java中发送数据
rightFragment.setData("GetDataFromMain");
2.2、Fragment传递数据给Activity
通过接口回调获取数据
- step1：在RightFragment.java中定义一个接口以及设置接口的方法
public onDataTransmissionListener mListener;
public interface onDataTransmissionListener {
public void dataTransmission(String data);
}
public void setOnDataTransmissionListener(onDataTransmissionListener mListener) {
this.mListener = mListener;
}
- step2：在RightFragment.java中通过接口传递数据
if (mListener != null) {
mListener.dataTransmission(btnTextTwo.getText().toString());
}
- step3：在MianActivityFour.java中设置Fragment并监听RightFragment.java的接口
RightFragment rightFragment = new RightFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fl_right, rightFragment, "rightFragment");
transaction.commit();
rightFragment.setOnDataTransmissionListener(new RightFragment.onDataTransmissionListener() {
@Override
public void dataTransmission(String data) {
String fgData = data; //获取Fragment传过来的内容
}
});
3、Fragment与Fragment
先创建一个简单的布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
tools:context=".MainActivityFour"
android:orientation="horizontal">
<FrameLayout
android:id="@+id/fl_left"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"/>
<FrameLayout
android:id="@+id/fl_right"
android:layout_width="0dp"
android:layout_weight="2"
android:layout_height="match_parent"/>
</LinearLayout>
3.1、获取Fragment的id或Tag
核心代码如下，
- step1：在MainActivityFour.java中设置Fragment
LeftFragment leftFragment = new LeftFragment();
RightFragment rightFragment = new RightFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fl_left, leftFragment, "leftFragment");
transaction.replace(R.id.fl_right, rightFragment, "rightFragment");
transaction.commit();
- step2：在RightFragment.java中定义一个接收数据的方法
public void setData(String dataMsg) {
tvShowContent.setText(dataMsg);
}
- step3：在LeftFragment.java中根据FragmentID或FragmentTag获取RightFragment对象
RightFragment rightFragment = (RightFragment) getActivity()
.getSupportFragmentManager().findFragmentById(R.id.fl_right);
rightFragment.setData(btnTextOne.getText().toString());
或
RightFragment rightFragment = (RightFragment) getActivity()
.getSupportFragmentManager().findFragmentByTag("rightFragment");
rightFragment.setData(btnTextOne.getText().toString());
3.2、接口回调
- step1：在LeftFragment.java中定义一个接口以及设置接口的方法
public onDataTransmissionListener mListener;
public interface onDataTransmissionListener {
public void dataTransmission(String data);
}
public void setOnDataTransmissionListener(onDataTransmissionListener mListener) {
this.mListener = mListener;
}
- step2：在LeftFragment.java中通过接口传递数据
if (mListener != null) {
mListener.dataTransmission(btnTextTwo.getText().toString());
}
- step3：在RightFragment.java中定义一个接收数据的方法
public void setData(String dataMsg) {
tvShowContent.setText(dataMsg);
}
- step4：在MianActivityFour.java中设置Fragment并监听LeftFragment.java的接口
LeftFragment leftFragment = new LeftFragment();
RightFragment rightFragment = new RightFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fl_left, leftFragment, "leftFragment");
transaction.replace(R.id.fl_right, rightFragment, "rightFragment");
transaction.commit();
leftFragment.setOnDataTransmissionListener(new LeftFragment.onDataTransmissionListener() {
@Override
public void dataTransmission(String data) {
rightFragment.setData(data);
}
});
二、EventBus
上述Activity与Activity、Activity与Fragment以及Frament与Fragment之间的通信，都可以使用EventBus实现，具体步骤如下：
1、在app目录下的build.gradle文件中添加eventbus依赖；
implementation 'org.greenrobot:eventbus:3.0.0'
2、创建EventBus信息传递类；
public class EventInit {
private String name;
private String age;
private String sex;
private String grade;
private String school;
public EventInit(String name, String age, String sex, String grade, String school) {
this.name = name;
this.age = age;
this.sex = sex;
this.grade = grade;
this.school = school;
}
public String getAllValue() {
return "name: " + name
+ "\nage: " + age
+ "\nsex: " + sex
+ "\ngrade: " + grade
+ "\nschool: " + school;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
public String getSchool() {
return school;
}
public void setSchool(String school) {
this.school = school;
}
}
3、在发送消息的Activty或Fragment中使用下面代码；
EventBus.getDefault().post(new EventInit(name, age, sex, grade, school));
4、在接收数据的Activity或Fragment中注册和注销EventBus，并接收消息；
一般建议：
（1）在onStart()中注册EventBus.
@Override
protected void onStart() {
super.onStart();
//注册EventBus 接收数据
if (!EventBus.getDefault().isRegistered(this)) {
EventBus.getDefault().register(this);
}
}
（2）在onDestroy()中注销EventBus.
@Override
protected void onDestroy() {
super.onDestroy();
//注销事件接收
EventBus.getDefault().unregister(this);
}
（3）定义接收消息的方法
// 接收消息（post）
@Subscribe(threadMode = ThreadMode.MAIN)
public void onEventInit(EventInit eventInit) {
try {
String allValue = eventInit.getAllValue();
//更改TextView内容
tvReceiveText.setText(allValue);
} catch (Exception e) {
e.printStackTrace();
}
}
5、运行程序后，可能会出现如下问题；
（1）在Run窗口可以看到下面的提示，但并不会报错；
EventBus ： No subscribers registered for event class
（2）以上问题是由于EventBus不适合向一个不存在于activity栈中的activity发送消息，这样是失败的，fragment同理。
例如：
情况1：一个activity 还没有生成，就post，肯定报这样的错；
情况2：一个activity曾经生成了，但是不在activity栈中了，也是收不到消息的
情况3：生命周期的问题。如果是在onStop()方法中注销了EventBus，而在特殊情况下恰好调用了接收消息的Activty或Fragment中的onStop()方法，这也就出现了上述的问题。
6、解决方法；
（1）依旧使用上述的post方式发送消息，不过需要加上延时操作，如下：
//延时发送数据
new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
EventBus.getDefault().post(new EventInit(name, age, sex, grade, school));
}
}).start();
（2）或者使用postSticky方式替换post方式发送消息，如下：
//使用粘性事件
EventBus.getDefault().postSticky(new EventInit(name, age, sex, grade, school));
在接收消息的Activity或Fragment中定义接收消息的方法：
// 接收消息（postStick）
@Subscribe(threadMode = ThreadMode.MAIN, sticky = true)
public void onEventInitTwo(EventInit eventInit) {
try {
String allValue = eventInit.getAllValue();
//更改TextView内容
tvReceiveText.setText(allValue);
} catch (Exception e) {
e.printStackTrace();
}
}
（3）post与postSticky相比，若post事件没有被订阅，则该事件会被流传，即作废；而postSicky是将完整的事件放到内存中，待EventBus注册时再从内存中获取该事件，然后包装成一个新的post事件进行发布，由于此时EventBus注册已执行完毕，所以postSticky事件可以正常使用。