47. Intent

47. Intent

47.1 Intent基本类型

新建工程

更改下名字

new Activity2

Activity1布局

新建一个跳转按钮

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".simple01.MainActivity1">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="跳转"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:onClick="startAction"
        />
</androidx.constraintlayout.widget.ConstraintLayout>

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

import com.dingjiaxiong.myintent.R;

public class MainActivity1 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main1);
    }

    public void startAction(View view) {
        Intent intent = new Intent(this,MainActivity2.class);

        intent.putExtra("name","dingjiaxiong");
        intent.putExtra("sex","M");

        startActivity(intent);
    }
}

 

2

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

import com.dingjiaxiong.myintent.R;

public class MainActivity2 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        //接收
        Intent intent = getIntent();
        String name = intent.getStringExtra("name");
        char sex = intent.getCharExtra("sex",'A');

        Toast.makeText(this,"name:" + name + "sex:" + sex,Toast.LENGTH_SHORT).show();

    }
}

运行

47.2 Intent传递Bundle
1

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.dingjiaxiong.myintent.R;

public class MainActivity1 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main1);

    }

    public void startAction(View view) {
        Intent intent = new Intent(this,MainActivity2.class);

        //封装Bundle对象
        Bundle bundle = new Bundle();
        bundle.putString("name","dingjiaxiong");
        bundle.putChar("sex",'M');

        //通过intent
        intent.putExtras(bundle);

        startActivity(intent);
    }
}

 

2

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

import com.dingjiaxiong.myintent.R;

public class MainActivity2 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        //接收，拆Bundle
        Intent intent = getIntent();

        String name = intent.getStringExtra("name");
        char sex = intent.getCharExtra("sex",'A');

        Toast.makeText(this,"name:" + name + "sex:" + sex,Toast.LENGTH_SHORT).show();

    }
}

运行

就只是封装一下，嗯。

47.3 传递Serializable接口
创建一个Student类

package com.dingjiaxiong.myintent.simple01;

import java.io.Serializable;

//必须实现这个接口，才能传递
public class Student implements Serializable {
    
    public int id;
    
    public String name;
    
    public int age;
    
}

1

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.dingjiaxiong.myintent.R;

public class MainActivity1 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main1);

    }

    public void startAction(View view) {
        Intent intent = new Intent(this,MainActivity2.class);

        Student student = new Student();
        student.id = 9;
        student.name = "dingjiaxiong";
        student.age = 22;

        intent.putExtra("Student",student);

        startActivity(intent);
    }
}

 

2

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

import com.dingjiaxiong.myintent.R;

import java.io.Serializable;

public class MainActivity2 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        //接收对象
        Intent intent = getIntent();

        Student student = (Student) intent.getSerializableExtra("Student");

        Toast.makeText(this,"student.id:" + student.id + "student.name:" + student.name,Toast.LENGTH_SHORT).show();

    }
}

运行

47.4 传递Parcelable接口
Student.java

package com.dingjiaxiong.myintent.simple01;

import android.os.Parcel;
import android.os.Parcelable;

import java.io.Serializable;

//成为Parcelable子类
public class Student implements Parcelable {

    public Student(){}

    public String name;
    public int age;

    protected Student(Parcel in) {
        name = in.readString();
        age = in.readInt();
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(name);
        dest.writeInt(age);
    }

    @Override
    public int describeContents() {
        return 0;
    }

    public static final Creator<Student> CREATOR = new Creator<Student>() {
        @Override
        public Student createFromParcel(Parcel in) {
            return new Student(in);
        }

        @Override
        public Student[] newArray(int size) {
            return new Student[size];
        }
    };
}

 

1

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.dingjiaxiong.myintent.R;

public class MainActivity1 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main1);

    }

    public void startAction(View view) {
        Intent intent = new Intent(this,MainActivity2.class);

        //传递Parceable对象

        Student student = new Student();
        student.name = "dingjiaxiong";
        student.age = 22;

        intent.putExtra("student",student);

        startActivity(intent);
    }
}

 

2

package com.dingjiaxiong.myintent.simple01;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

import com.dingjiaxiong.myintent.R;

import java.io.Serializable;

public class MainActivity2 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        //接收对象
        Intent intent = getIntent();

        Student student = intent.getParcelableExtra("student");

        Toast.makeText(this,"student.age:" + student.age + "student.name:" + student.name,Toast.LENGTH_SHORT).show();

    }
}

运行

最好是使用Parcelable。因为其兼容安卓虚拟机，比Ser性能高很多。