Android项目之简单计算器

MainActivity.java

package com.LC.jsq;

import java.text.DecimalFormat;

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

public class MainActivity extends Activity implements OnClickListener {
Button btn0 = null;
Button btn1 = null;
Button btn2 = null;
Button btn3 = null;
Button btn4 = null;
Button btn5 = null;
Button btn6 = null;
Button btn7 = null;
Button btn8 = null;
Button btn9 = null;
Button btnBackspace = null;
Button btnCE = null;
Button btnAdd = null;
Button btnSub = null;
Button btnMul = null;
Button btnDiv = null;
Button btnEqu = null;
Button btnpoint = null;
Button btnPom = null;
TextView tvResult = null;
StringBuffer str_display = new StringBuffer();
double num1 = 0, num2 = 0;
double Result = 0;
int op = 0;
boolean isClickEqu = false;
double get_double;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn0 = (Button) findViewById(R.id.btn0);
btn1 = (Button) findViewById(R.id.btn1);
btn2 = (Button) findViewById(R.id.btn2);
btn3 = (Button) findViewById(R.id.btn3);
btn4 = (Button) findViewById(R.id.btn4);
btn5 = (Button) findViewById(R.id.btn5);
btn6 = (Button) findViewById(R.id.btn6);
btn7 = (Button) findViewById(R.id.btn7);
btn8 = (Button) findViewById(R.id.btn8);
btn9 = (Button) findViewById(R.id.btn9);
btnBackspace = (Button) findViewById(R.id.btnBackspace);
btnCE = (Button) findViewById(R.id.btnCE);
btnEqu = (Button) findViewById(R.id.btnEqu);
btnAdd = (Button) findViewById(R.id.btnAdd);
btnSub = (Button) findViewById(R.id.btnSub);
btnMul = (Button) findViewById(R.id.btnMul);
btnDiv = (Button) findViewById(R.id.btnDiv);
btnpoint = (Button) findViewById(R.id.btnpoint);
btnPom = (Button) findViewById(R.id.btnpom);
tvResult = (TextView) findViewById(R.id.tvResult);

btnBackspace.setOnClickListener(this);
btnCE.setOnClickListener(this);

btn0.setOnClickListener(this);
btn1.setOnClickListener(this);
btn2.setOnClickListener(this);
btn3.setOnClickListener(this);
btn4.setOnClickListener(this);
btn5.setOnClickListener(this);
btn6.setOnClickListener(this);
btn7.setOnClickListener(this);
btn8.setOnClickListener(this);
btn9.setOnClickListener(this);

btnAdd.setOnClickListener(this);
btnSub.setOnClickListener(this);
btnMul.setOnClickListener(this);
btnDiv.setOnClickListener(this);
btnEqu.setOnClickListener(this);
btnpoint.setOnClickListener(this);
btnPom.setOnClickListener(this);

}

public void onClick(View v) {

switch (v.getId()) {
case R.id.btnBackspace:
String myStr = tvResult.getText().toString();
op = 0;

try {
tvResult.setText(myStr.substring(0, myStr.length() - 1));
} catch (Exception e) {
tvResult.setText("");
}

break;
case R.id.btnCE:
tvResult.setText(null);
op = 0;
break;

case R.id.btnpoint:
String num3 = tvResult.getText().toString();
if (num3.indexOf(".") < 0) {
if (num3.length() == 0) {
tvResult.setText(0 + ".");
} else {
tvResult.setText(num3 + ".");
}
} else {
tvResult.setText(num3);
}
break;
case R.id.btn0:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString = tvResult.getText().toString();
if (myString.length() == 0) {
return;

}
myString += "0";
tvResult.setText(myString);
break;
case R.id.btn1:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString1 = tvResult.getText().toString();
myString1 += "1";
tvResult.setText(myString1);
break;
case R.id.btn2:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString2 = tvResult.getText().toString();
myString2 += "2";
tvResult.setText(myString2);
break;
case R.id.btn3:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString3 = tvResult.getText().toString();
myString3 += "3";
tvResult.setText(myString3);
break;
case R.id.btn4:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString4 = tvResult.getText().toString();
myString4 += "4";
tvResult.setText(myString4);
break;
case R.id.btn5:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString5 = tvResult.getText().toString();
myString5 += "5";
tvResult.setText(myString5);
break;
case R.id.btn6:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString6 = tvResult.getText().toString();
myString6 += "6";
tvResult.setText(myString6);
break;
case R.id.btn7:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString7 = tvResult.getText().toString();
myString7 += "7";
tvResult.setText(myString7);
break;
case R.id.btn8:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString8 = tvResult.getText().toString();
myString8 += "8";
tvResult.setText(myString8);
break;
case R.id.btn9:
if (isClickEqu) {
tvResult.setText(null);
isClickEqu = false;
}
String myString9 = tvResult.getText().toString();
myString9 += "9";
tvResult.setText(myString9);
break;

case R.id.btnAdd:
String myStringAdd = tvResult.getText().toString();
if (myStringAdd.equals("")) {
return;
}
num1 = Double.valueOf(myStringAdd);
tvResult.setText(null);
op = 1;
isClickEqu = false;
break;

case R.id.btnSub:
String myStringSub = tvResult.getText().toString();
if (myStringSub.equals("")) {
return;
}
num1 = Double.valueOf(myStringSub);
tvResult.setText(null);
op = 2;
isClickEqu = false;
break;
case R.id.btnMul:
String myStringMul = tvResult.getText().toString();
if (myStringMul.equals("")) {
return;
}
num1 = Double.valueOf(myStringMul);
tvResult.setText(null);
op = 3;
isClickEqu = false;
break;
case R.id.btnDiv:
String myStringDiv = tvResult.getText().toString();
if (myStringDiv.equals("")) {
return;
}
num1 = Double.valueOf(myStringDiv);
tvResult.setText(null);
op = 4;
isClickEqu = false;
break;
case R.id.btnpom:
String myStringPom = (String) tvResult.getText();
if (myStringPom.equals("0"))
return;
if (myStringPom.startsWith("-")) {
tvResult.setText(myStringPom.substring(1));
return;
}
tvResult.setText("-" + myStringPom);
break;
case R.id.btnEqu:
String myStringEqu = tvResult.getText().toString();
if (myStringEqu.equals("")) {
return;
}
if (Double.valueOf(myStringEqu) == get_double) {
return;
}
num2 = Double.valueOf(myStringEqu);
switch (op) {
case 0:
Result = num2;
break;
case 1:
Result = num1 + num2;
break;
case 2:
Result = num1 - num2;
break;
case 3:
Result = num1 * num2;
break;
case 4:
if (num2 == 0) {
return;
}
Result = num1 / num2;
break;
default:
Result = 0;
break;
}
DecimalFormat df = new DecimalFormat("#.####");
get_double = Double.parseDouble(df.format(Result));
tvResult.setText(String.valueOf(get_double));
isClickEqu = true;
break;
default:
break;
}
}
}

activity_main.xml

<LinearLayout 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"
android:background="#ADADAD"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
android:id="@+id/tvResult"
android:layout_width="fill_parent"
android:layout_height="60dip"
android:background="@drawable/white_bg"
android:gravity="bottom|right"
android:textColor="#000000"
android:textSize="20sp" />

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="20dip"
android:gravity="center_horizontal"
android:orientation="vertical" >

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:orientation="horizontal" >

<Button
android:id="@+id/btnCE"
android:layout_width="70dp"
android:layout_height="70dp"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="C"
android:textSize="20sp" />

<Button
android:id="@+id/btnBackspace"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="←"
android:textSize="20sp" />

<Button
android:id="@+id/btnDiv"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="÷"
android:textSize="20sp" />

<Button
android:id="@+id/btnMul"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="×"
android:textSize="20sp" />
</LinearLayout>

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:gravity="center_horizontal"
android:orientation="horizontal" >

<Button
android:id="@+id/btn7"
android:layout_width="70dp"
android:layout_height="70dp"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="7"
android:textSize="20sp" />

<Button
android:id="@+id/btn8"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="8"
android:textSize="20sp" />

<Button
android:id="@+id/btn9"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="9"
android:textSize="20sp" />

<Button
android:id="@+id/btnSub"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="－"
android:textSize="20sp" />
</LinearLayout>

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:gravity="center_horizontal"
android:orientation="horizontal" >

<Button
android:id="@+id/btn4"
android:layout_width="70dp"
android:layout_height="70dp"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="4"
android:textSize="20sp" />

<Button
android:id="@+id/btn5"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="5"
android:textSize="20sp" />

<Button
android:id="@+id/btn6"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="6"
android:textSize="20sp" />

<Button
android:id="@+id/btnAdd"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="＋"
android:textSize="20sp" />
</LinearLayout>

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:gravity="center_horizontal"
android:orientation="horizontal" >

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >

<Button
android:id="@+id/btn1"
android:layout_width="70dp"
android:layout_height="70dp"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="1"
android:textSize="20sp" />

<Button
android:id="@+id/btn2"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="2"
android:textSize="20sp" />

<Button
android:id="@+id/btn3"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="3"
android:textSize="20sp" />

<Button
android:id="@+id/btnpom"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="±"
android:textSize="20sp" />
</LinearLayout>

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:orientation="horizontal" >

<Button
android:id="@+id/btn0"
android:layout_width="150dp"
android:layout_height="70dp"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="0"
android:textSize="20sp" />

<Button
android:id="@+id/btnpoint"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:text="."
android:textSize="20sp" />

<Button
android:id="@+id/btnEqu"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="10dip"
android:paddingBottom="10dp"
android:paddingRight="10dp"
android:background="@drawable/orange_selector"
android:text="="
android:textSize="20sp" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>

</LinearLayout>