1创建工程
注意这个名称的命名：
3. UC结构及相关代码
UC.java 用于执行单位换算的Activity
// UC.javapackage com.apress.uc;import android.app.Activity;import android.os.Bundle;import android.text.Editable;import android.text.TextWatcher;import android.view.View;import android.widget.AdapterView;import android.widget.ArrayAdapter;import android.widget.Button;import android.widget.EditText;import android.widget.Spinner;public class UC extends Activity{ private int position = 0; private double[] multipliers = { 0.0015625, // Acres to square miles 101325.0, // Atmospheres to Pascals 100000.0, // Bars to Pascals 0, // Degrees Celsius to Degrees Fahrenheit (placeholder) 0, // Degrees Fahrenheit to Degrees Celsius (placeholder) 0.00001, // Dynes to Newtons 0.3048, // Feet/Second to Metres/Second 0.0284130625, // Fluid Ounces (UK) to Litres 0.0295735295625, // Fluid Ounces (US) to Litres 746.0, // Horsepower (electric) to Watts 735.499, // Horsepower (metric) to Watts 1/1016.0469088, // Kilograms to Tons (UK or long) 1/907.18474, // Kilograms to Tons (US or short) 1/0.0284130625, // Litres to Fluid Ounces (UK) 1/0.0295735295625, // Litres to Fluid Ounces (US) 331.5, // Mach Number to Metres/Second 1/0.3048, // Metres/Second to Feet/Second 1/331.5, // Metres/Second to Mach Number 0.833, // Miles/Gallon (UK) to Miles/Gallon (US) 1/0.833, // Miles/Gallon (US) to Miles/Gallon (UK) 100000.0, // Newtons to Dynes 1/101325.0, // Pascals to Atmospheres 0.00001, // Pascals to Bars 640.0, // Square Miles to Acres 1016.0469088, // Tons (UK or long) to Kilograms 907.18474, // Tons (US or short) to Kilograms 1/746.0, // Watts to Horsepower (electic) 1/735.499 // Watts to Horsepower (metric) }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); final EditText etUnits = (EditText) findViewById(R.id.units); final Spinner spnConversions = (Spinner) findViewById(R.id.conversions); ArrayAdapter aa; aa = ArrayAdapter. createFromResource(this, R.array.conversions, android.R.layout.simple_spinner_item); aa.setDropDownViewResource(android.R.layout.simple_spinner_item); spnConversions.setAdapter(aa); AdapterView.OnItemSelectedListener oisl; oisl = new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView parent, View view, int position, long id) { UC.this.position = position; } @Override public void onNothingSelected(AdapterView parent) { System.out.println("nothing"); } }; spnConversions.setOnItemSelectedListener(oisl); final Button btnClear = (Button) findViewById(R.id.clear); AdapterView.OnClickListener ocl; ocl = new AdapterView.OnClickListener() { @Override public void onClick(View v) { etUnits.setText(""); } }; btnClear.setOnClickListener(ocl); btnClear.setEnabled(false); final Button btnConvert = (Button) findViewById(R.id.convert); ocl = new AdapterView.OnClickListener() { @Override public void onClick(View v) { String text = etUnits.getText().toString(); double input = Double.parseDouble(text); double result = 0; if (position == 3) result = input*9.0/5.0+32; // Celsius to Fahrenheit else if (position == 4) result = (input-32)*5.0/9.0; // Fahrenheit to Celsius else result = input*multipliers[position]; etUnits.setText(""+result); } }; btnConvert.setOnClickListener(ocl); btnConvert.setEnabled(false); Button btnClose = (Button) findViewById(R.id.close); ocl = new AdapterView.OnClickListener() { @Override public void onClick(View v) { finish(); } }; btnClose.setOnClickListener(ocl); TextWatcher tw; tw = new TextWatcher() { @Override public void afterTextChanged(Editable s) { } @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void onTextChanged(CharSequence s, int start, int before, int count) { if (etUnits.getText().length() == 0) { btnClear.setEnabled(false); btnConvert.setEnabled(false); } else { btnClear.setEnabled(true); btnConvert.setEnabled(true); } } }; etUnits.addTextChangedListener(tw); }} main.xml 用于保存小部件和布局信息的main.xml文件
strings.xml 保存了应用中的字符串
Units Converter Clear Close Convert Select a conversion Units
arrays.xml 文件中保存了换算类型的字符串数组
- Acres to Square Miles
- Atmospheres to Pascals
- Bars to Pascals
- Degrees Celsius to Degrees Fahrenheit
- Degrees Fahrenheit to Degrees Celsius
- Dynes to Newtons
- Feet/Second to Metres/Second
- Fluid Ounces (UK) to Litres
- Fluid Ounces (US) to Litres
- Horsepower (electric) to Watts
- Horsepower (metric) to Watts
- Kilograms to Tons (UK or long)
- Kilograms to Tons (US or short)
- Litres to Fluid ounces (UK)
- Litres to Fluid ounces (US)
- Mach Number to Metres/Second
- Metres/Second to Feet/Second
- Metres/Second to Mach Number
- Miles/Gallon (UK) to Miles/Gallon (US)
- Miles/Gallon (US) to Miles/Gallon (UK)
- Newtons to Dynes
- Pascals to Atmospheres
- Pascals to Bars
- Square Miles to Acres
- Tons (UK or long) to Kilograms
- Tons (US or short) to Kilograms
- Watts to Horsepower (electric)
- Watts to Horsepower (metric)
gradientbg.xml 文件保存了用于Activity背景色的渐变形状
4 虚拟机运行结果
注意：
其中的uc.xml 换成以下代码可以运行