Android Simple Calculator

This example is a calculator implementation example based on the Android GOOGL SDK book:

1 Create three TextView objects, two EditText objects, four button objects

Main.xml for

<?xml version= "1.0" encoding= "Utf-8"?>

<absolutelayout

Android:id= "@+id/widget0"

Android:layout_width= "Fill_parent"

android:layout_height= "Fill_parent"

Xmlns:android= "Http://schemas.android.com/apk/res/android"

>

<edittext android:id= "@+id/edittext1"

android:layout_height= "Wrap_content"

Android:layout_width= "47PX"

Android:textsize= "18SP"

android:layout_x= "26PX"

Android:layout_y= "52px"

/>

<edittext android:id= "@+id/edittext2"

android:layout_height= "Wrap_content"

Android:layout_width= "45px"

Android:textsize= "18SP"

android:layout_x= "128px"

android:layout_y= "51px"/>

<textview

Android:id= "@+id/mytextview1"

Android:layout_width= "30px"

android:layout_height= "33PX"

Android:textsize= "18SP"

android:layout_x= "92px"

Android:layout_y= "60px"

/>

<textview

Android:id= "@+id/mytextview3"

Android:layout_width= "18px"

android:layout_height= "Wrap_content"

android:text= "="

Android:textsize= "18SP"

android:layout_x= "189PX"

Android:layout_y= "63PX"

/>

<textview

Android:id= "@+id/mytextview2"

Android:layout_width= "30px"

android:layout_height= "Wrap_content"

Android:textsize= "18SP"

android:layout_x= "219PX"

Android:layout_y= "61px"

/>

<button

Android:id= "@+id/button1"

Android:layout_width= "Wrap_content"

android:layout_height= "Wrap_content"

Android:textsize= "25SP"

android:layout_x= "12px"

Android:layout_y= "161px"

android:text= "@string/but_str1"/>

<button

Android:id= "@+id/button2"

Android:layout_width= "Wrap_content"

android:layout_height= "Wrap_content"

Android:textsize= "25SP"

android:layout_x= "85px"

Android:layout_y= "159PX"

android:text= "@string/but_str2"/>

<button

Android:id= "@+id/button3"

Android:layout_width= "Wrap_content"

android:layout_height= "Wrap_content"

Android:textsize= "25SP"

android:layout_x= "158px"

Android:layout_y= "161px"

android:text= "@string/but_str3"/>

<button

Android:id= "@+id/button4"

Android:layout_width= "Wrap_content"

android:layout_height= "Wrap_content"

Android:textsize= "25SP"

android:layout_x= "239PX"

Android:layout_y= "161px"

android:text= "@string/but_str4"/>

</AbsoluteLayout>

There's a little bit of a problem here.

The contents of the button display are obtained through string.xml. You can also directly modify the android:text= "+" in Main.xml to specify "+" as specified above.

Activity Object

Package com.app.android;

Import Java.text.DecimalFormat;

Import Java.text.NumberFormat;

Import android.app.Activity;

Import Android.app.AlertDialog;

Import Android.app.AlertDialog.Builder;

Import Android.content.DialogInterface;

Import Android.content.DialogInterface.OnClickListener;

Import Android.os.Bundle;

Import Android.view.View;

Import Android.widget.Button;

Import Android.widget.EditText;

Import Android.widget.TextView;

public class Myfirstactivity extends Activity {

/** called when the activity is first created. */

Private Button button1;

Private TextView TextView1;

Private TextView textView2;

Private Button button2;

Private Button Button3;

Private Button Button4;

Private EditText EditText1;

Private EditText editText2;

@Override

public void OnCreate (Bundle savedinstancestate) {

Super.oncreate (savedinstancestate);

Setcontentview (R.layout.main);

button1= (Button) Findviewbyid (R.id.button1);

Button2= (Button) Findviewbyid (R.id.button2);

button3= (Button) Findviewbyid (R.id.button3);

button4= (Button) Findviewbyid (R.ID.BUTTON4);

edittext1= (EditText) Findviewbyid (R.ID.EDITTEXT1);

Edittext2= (EditText) Findviewbyid (R.ID.EDITTEXT2);

textview1= (TextView) Findviewbyid (R.ID.MYTEXTVIEW1);

Textview2= (TextView) Findviewbyid (R.ID.MYTEXTVIEW2);

Button1.setonclicklistener (New Button.onclicklistener ()

{

public void OnClick (View v)

{

TODO auto-generated Method Stub

if (Confirm (edittext1,edittext2)) {

Textview1.settext ("+");

String Strret=format (Float.parsefloat (Edittext1.gettext (). toString ()) +float.parsefloat (Edittext2.gettext (). ToString ()));

Textview2.settext (strret);

}

}

});

Button2.setonclicklistener (New Button.onclicklistener ()

{

public void OnClick (View v)

{

TODO auto-generated Method Stub

if (Confirm (edittext1,edittext2)) {

Textview1.settext ("-");

String Strret=format (Float.parsefloat (Edittext1.gettext (). toString ())-float.parsefloat (Edittext2.gettext (). ToString ()));

Textview2.settext (strret);

}

}

});

Button3.setonclicklistener (New Button.onclicklistener ()

{

public void OnClick (View v)

{

TODO auto-generated Method Stub

if (Confirm (edittext1,edittext2)) {

Textview1.settext ("*");

String Strret=format (Float.parsefloat (Edittext1.gettext (). toString ()) *float.parsefloat (Edittext2.gettext (). ToString ()));

Textview2.settext (strret);

}}

});

Button4.setonclicklistener (New Button.onclicklistener ()

{

public void OnClick (View v)

{

TODO auto-generated Method Stub

if (Confirm (edittext1,edittext2)) {;

Textview1.settext ("/");

String Strret=format (Float.parsefloat (Edittext1.gettext (). toString ())/float.parsefloat (Edittext2.gettext (). ToString ()));

Textview2.settext (strret);

}}

});

}

/**

* Formatting results

* @param num

* @return

*/

Private String format (float num) {

NumberFormat formater=new DecimalFormat ("0.00");

String S=formater.format (num);

return s;

}

/**

* Verify that the operation is complete

* @param Text1

* @param text2

* @return

*/

Private Boolean confirm (EditText Text1,edittext text2) {

String Edittext1=text1.gettext (). toString ();

String Edittext2=text2.gettext (). toString ();

System.out.println (edittext1+ "," +edittext2);

if (Edittext1!=null&&edittext1.equals ("")) | | (Edittext2!=null&&edittext2.equals (""))) {

New Alertdialog.builder (Myfirstactivity.this). Settitle (R.string.title). Setmessage (r.string.msg). Setpositivebutton (

R.string.ok,new Dialoginterface.onclicklistener () {

public void OnClick (Dialoginterface dialoginterface,int i) {

Dialoginterface.dismiss ();

}

}

). Show ();

return false;

}

Else{return true;}

}

}

Methods are already commented.

For more examples, refer to: http://itlanbao.com/preview.aspx#1,0

Android Simple Calculator