Bundle数据在Activity之间传递

MainActivity 
package com.example.android_text3;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.Toast;

public class MainActivity extends Activity {
    EditText et;
    Button bt;
    RadioButton rb1;
    RadioButton rb2;
    String sex="";
    Double height=0.0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et=(EditText)findViewById(R.id.editText1);
        bt=(Button)findViewById(R.id.go);
        rb1=(RadioButton)findViewById(R.id.radio0);
        bt.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if(rb1.isChecked()){
                    sex="m";
                }else {
                    sex="w";
                }
                String textview=et.getText().toString();
                if (textview==null||textview.equals("")) {
                Toast.makeText(MainActivity.this, "请输入身高", Toast.LENGTH_LONG).show();
                } else {
                    height=Double.valueOf(textview);
                    Log.i("height",String.valueOf(height));
                    Intent intent=new Intent();
                    intent.setClass(MainActivity.this, SecondActivity.class);
                    Bundle extras=new Bundle();
                    extras.putString("sex", sex);
                    extras.putDouble("height", height);;
                    intent.putExtras(extras);
                    startActivityForResult(intent, 0);
                }
            
            }
        });
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        switch (resultCode) {
        case RESULT_OK:
            Bundle bundle=data.getExtras();
            Double weight=bundle.getDouble("weight");
            Toast.makeText(MainActivity.this, "体重为"+String.valueOf(weight), Toast.LENGTH_LONG).show();
            break;

        default:
            break;
        }
    }

}

SecondActivity.java

package com.example.android_text3;

import java.text.DecimalFormat;
import java.text.NumberFormat;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class SecondActivity extends Activity {
    TextView sex;
    TextView height;
    Button bt;
    Double weight;
    Intent intent;
    Bundle bundle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.secondlayout);
        sex = (TextView) findViewById(R.id.sex);
        String sexmessage = this.getIntent().getExtras().getString("sex");
        height = (TextView) findViewById(R.id.height);
        sex.setText("性别：" + getSex(sexmessage));
        height.setText("身高："+formatnum(this.getIntent().getExtras()
                .getDouble("height")));
        bt = (Button) findViewById(R.id.goback);
        weight = getWeight(sexmessage,
                this.getIntent().getExtras().getDouble("height"));
        intent = this.getIntent();
        bundle =intent.getExtras();
        bt.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                bundle.putDouble("weight", weight);
                intent.putExtras(bundle);
                SecondActivity.this.setResult(RESULT_OK, intent);
                SecondActivity.this.finish();
            }
        });
    }

    /**
     * 
     * @param values
     * @return
     */
    String formatnum(double values) {
        NumberFormat formatter = new DecimalFormat("0.00");
        String s = formatter.format(values);
        return s;
    }

    /**
     * 
     * @param sex
     * @return
     */
    String getSex(String sex) {
        if (sex.equals("w")) {
            sex = "女";
        } else {
            sex = "男";
        }
        return sex;
    }

    Double getWeight(String sex, Double height) {
        Double weight=0.0;
        if(sex.equals("m")){
            weight=(height-80)*0.7;
        }else{
            weight=(height-70)*0.8;
        }
        return weight;
    }
}

xml文件

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="${packageName}.${activityClass}" >

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/radioGroup1"
        android:layout_marginTop="42dp"
        android:layout_toLeftOf="@+id/radioGroup1"
        android:text="身高：" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/textView2"
        android:layout_alignBottom="@+id/textView2"
        android:layout_centerHorizontal="true"
        android:ems="10"
        android:inputType="number" />

    

    <RadioGroup
        android:id="@+id/radioGroup1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/editText1"
        android:orientation="horizontal" >

        <RadioButton
            android:id="@+id/radio0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="true"
            android:text="男" />

        <RadioButton
            android:id="@+id/radio1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="女" />
    </RadioGroup>

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/radioGroup1"
        android:layout_alignLeft="@+id/textView2"
        android:text="性别：" />

    <Button
        android:id="@+id/go"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText1"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="50dp"
        android:text="计算" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" 
    android:gravity="center_horizontal">

    <TextView
        android:id="@+id/sex"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/height"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <Button
        android:id="@+id/goback"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="返回" />

</LinearLayout>