Android开发--身高体重指数（BIM）计算--定义Android列表（Manifest）并添加新活动（Activity）
/* (程序头部注释开始)
* 程序的版权和版本声明部分
* Copyright (c) 2011, 烟台大学计算机学院学生
* All rights reserved.
* 文件名称：修改表达用户界面
* 作 者： 雷恒鑫
* 完成日期： 2012 年 08 月 08 日
* 版 本 号： V1.0
* 对任务及求解方法的描述部分
* 输入描述：
* 问题描述：
* 程序输出：
* 程序头部的注释结束
*/
Activity 分为独立的Activity和相依赖的Activity。
下面是对独立的Activity所做的实验：
新增加的“report.java”程序为：
package com.demo.android.bmi;import java.text.DecimalFormat;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class Report extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.report);findViews();showResults();setListensers();}private Button button_calc;private TextView view_result;private TextView view_suggest;private void findViews() {button_calc = (Button) findViewById(R.id.report_back);view_result = (TextView) findViewById(R.id.result);view_suggest = (TextView) findViewById(R.id.suggest);}// Listen for button clicksprivate void setListensers() {button_calc.setOnClickListener(backMain);}private Button.OnClickListener backMain = new Button.OnClickListener() {public void onClick(View v) {//Close this ActivityReport.this.finish();}};private void showResults(){DecimalFormat nf = new DecimalFormat("0.00");Bundle bunde = this.getIntent().getExtras();double height = Double.parseDouble(bunde.getString("KEY_HEIGHT")) / 100;double weight = Double.parseDouble(bunde.getString("KEY_WEIGHT"));double BMI = weight / (height * height);// Present resultview_result.setText(getString(R.string.bmi_result)+ nf.format(BMI));// Give health adviceif (BMI > 25) {view_result.setText(R.string.advice_heavy);} else if (BMI < 20) {view_result.setText(R.string.advice_light);} else {view_result.setText(R.string.advice_average);}}}
修改后的“Bmi.java”程序为：
package com.demo.android.bmi;import java.net.URISyntaxException;import java.text.DecimalFormat;import android.app.Activity;import android.app.AlertDialog;import android.content.DialogInterface;import android.content.Intent;import android.content.res.ColorStateList;import android.content.res.Resources;import android.content.res.XmlResourceParser;import android.net.Uri;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.view.View.OnTouchListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;public class Bmi extends Activity {/** * Called when the activity is first created. * * @param <calcBMI> */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);findViews();setListensers();}private Button button_calc;private EditText field_height;private EditText field_weight;private TextView view_result;private TextView view_suggest;private void findViews() {button_calc = (Button) findViewById(R.id.submit);field_height = (EditText) findViewById(R.id.height);field_weight = (EditText) findViewById(R.id.weight);view_result = (TextView) findViewById(R.id.result);view_suggest = (TextView) findViewById(R.id.suggest);}// Listen for button clicksprivate void setListensers() {button_calc.setOnClickListener(calcBMI);}private Button.OnClickListener calcBMI = new Button.OnClickListener() {public void onClick(View v) {//Switch to report pageIntent intent = new Intent();intent.setClass(Bmi.this, Report.class);Bundle bundle = new Bundle();bundle.putString("KEY_HEIGHT", field_height.getText().toString());bundle.putString("KEY_WEIGHT", field_weight.getText().toString());intent.putExtras(bundle);startActivity(intent);} };}
运行结果：
经验积累：
1.我学会了如何使用Intent传递数据。
2.我学会了使用Intent接收信息。