Android 多个界面(Activity)

1.介绍

Android 多个界面(Activity)-LMLPHP

2.相关属性

(1)启动Activity

Android 多个界面(Activity)-LMLPHP

(2)Intent介绍

Android 多个界面(Activity)-LMLPHP

(3)关闭Activity

Android 多个界面(Activity)-LMLPHP

3.多个页面之间传递数据(页面1向页面2传递数据，单向传递数据)

(1)相关属性

Android 多个界面(Activity)-LMLPHP

注意：data为str的代号

(2)xml文件

第一个界面

<?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"

    android:orientation="vertical"

    tools:context=".MainActivity">

    <TextView

        android:id="@+id/tv_weight"

        android:layout_gravity="center"

        android:layout_width="wrap_content"

        android:layout_height="50dp"

        android:text="这是标准体重计算界面"

        android:textSize="30dp" />

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:orientation="horizontal"

        android:gravity="center">

        <TextView

            android:id="@+id/tv_gender"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="请选择性别" />

        <RadioGroup

            android:layout_width="wrap_content"

            android:layout_height="match_parent"

            android:orientation="horizontal">

            <RadioButton

                android:id="@+id/radioButton"

                android:layout_width="wrap_content"

                android:layout_height="wrap_content"

                android:text="男" />

            <RadioButton

                android:id="@+id/radioButton2"

                android:layout_width="wrap_content"

                android:layout_height="wrap_content"

                android:text="女" />

        </RadioGroup>

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:orientation="horizontal"

        android:gravity="center">

        <TextView

            android:id="@+id/tv_userheight"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="请输入您的身高" />

        <EditText

            android:id="@+id/et_userheight"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:ems="10"

            android:inputType="textPersonName" />

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:orientation="horizontal"

        android:gravity="center">

        <Button

            android:id="@+id/bt_calculate"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="计算" />

    </LinearLayout>

</LinearLayout>

第二个界面

<?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"

    android:orientation="vertical"

    tools:context=".MainActivity">

    <TextView

        android:id="@+id/textView"

        android:layout_gravity="center"

        android:layout_width="wrap_content"

        android:layout_height="50dp"

        android:text="这是第二个界面"

        android:textSize="30dp" />

    <Button

        android:id="@+id/bt_goback"

        android:layout_gravity="center"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="返回" />

    <EditText

        android:id="@+id/et_message"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:ems="10"

        android:inputType="textPersonName"

        android:text="Name" />

    <EditText

        android:id="@+id/et_weightValue"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:ems="10"

        android:inputType="textPersonName"

        android:text="Name" />

</LinearLayout>

(3)java后台代码

界面1

package com.lucky.test31activity;

import android.content.Intent;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.RadioButton;

public class MainActivity extends AppCompatActivity {

    Button bt_calculate;

    EditText et_height;

    RadioButton radioButton;

    String gender;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        bt_calculate=findViewById(R.id.bt_calculate);

        et_height=findViewById(R.id.et_userheight);

        radioButton=findViewById(R.id.radioButton);

        bt_calculate.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                //实现页面之间的跳转

                Intent intent=new Intent(MainActivity.this,SecondActivity.class);

                //若页面之间要传递数据，可以用putExtra()方法，若不需要传递数据则下面两句可以不写

                //toString()一定不能少

                if(radioButton.isChecked()){

                    gender="男";

                }else {

                    gender="女";

                }

                intent.putExtra("003",gender);

                intent.putExtra("004",Integer.parseInt(et_height.getText().toString()));

                startActivity(intent); //进行页面跳转

            }

        });

    }

}

界面2

package com.lucky.test31activity;

import android.content.Intent;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

public class SecondActivity extends AppCompatActivity {

    Button button1;

    EditText et_message;

    EditText et_userweight;

    int userheight;

    double userweight;

    String gender;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_second);

        button1=findViewById(R.id.bt_goback);

        et_message=findViewById(R.id.et_message);

        et_userweight=findViewById(R.id.et_weightValue);

        Intent intent=getIntent();//获取Intent

        String name=intent.getStringExtra("001");

        String pwd=intent.getStringExtra("002");

        gender=intent.getStringExtra("003");

        userheight=intent.getIntExtra("004",0);

        if(gender.equals("男")){

            userweight=(userheight-80)*0.7;

        }else {

            userweight=(userheight-70)*0.6;

        }

        et_message.setText("用户名为："+name+"\n密码为："+pwd);

        et_userweight.setText("您的体重为："+userweight);

        button1.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                finish();//关闭页面

            }

        });

    }

}

4.页面之间传递数据(页面1与页面2双向传递数据)

(1)介绍

Android 多个界面(Activity)-LMLPHP

(2) java 后台代码

主界面

package com.lucky.test32activity2;

import android.content.Intent;

import android.support.annotation.Nullable;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    EditText page1output;

    EditText frompage2;

    Button button1;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        page1output=findViewById(R.id.editText_page1output);

        frompage2=findViewById(R.id.editText_frompage2);

        button1=findViewById(R.id.button_page1);

        button1.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Intent intent=new Intent(MainActivity.this,page2Activity.class);//实例化intent

                intent.putExtra("001",page1output.getText().toString()); //设置所传递的数据

                startActivityForResult(intent,0x01); //参数2为请求码

            }

        });

    }

    @Override

    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {

        //判断请求码与结果码是否一致

        if(requestCode==0x01&&resultCode==0x02){

            frompage2.setText(data.getStringExtra("002"));

        }

    }

}

第二界面

package com.lucky.test32activity2;

import android.content.Intent;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

public class page2Activity extends AppCompatActivity {

    EditText page1input;

    EditText page2return;

    Button button2;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_page2);

        page1input=findViewById(R.id.editText_page1input);

        page2return=findViewById(R.id.editText_page2return);

        button2=findViewById(R.id.button_page2);

        final Intent intent=getIntent();

        page1input.setText(intent.getStringExtra("001"));

        button2.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Intent intent1=new Intent(); //实例化intent

                intent1.putExtra("002",page2return.getText().toString()); //设置数据,toString()不能省略

                setResult(0x02,intent1); //从第二界面返回第一界面

                finish(); //关闭页面

            }

        });

    }

}

5.效果图

动态1对应工程名：test31,动态2对应工程名：test32

Android 多个界面(Activity)-LMLPHP