计算器
<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" 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/tv2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/et2" android:layout_centerVertical="true" android:gravity="center" android:text="显示计算结果" android:textStyle="italic" /> <EditText android:id="@+id/et2" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_above="@+id/tv2" android:layout_alignLeft="@+id/et1" android:ems="10" > <requestFocus /> </EditText> <EditText android:id="@+id/et1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_above="@+id/et2" android:layout_alignLeft="@+id/tv1" android:ems="10" /> <Button android:id="@+id/btn3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/btn1" android:layout_marginTop="16dp" android:layout_toRightOf="@+id/tv1" android:gravity="center" android:onClick="click" android:text="*" android:textColor="#000000" android:textSize="25sp" android:textStyle="italic" /> <Button android:id="@+id/btn4" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/btn3" android:layout_alignBottom="@+id/btn3" android:layout_toRightOf="@+id/btn3" android:gravity="center" android:onClick="click" android:text="÷" android:textColor="#000000" android:textSize="25sp" android:textStyle="italic" /> <TextView android:id="@+id/tv1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/btn1" android:layout_alignParentLeft="true" android:gravity="center" android:text="计算器" android:textColor="#000000" android:textSize="25sp" android:textStyle="italic" /> <Button android:id="@+id/btn2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@+id/btn3" android:layout_alignLeft="@+id/btn4" android:gravity="center" android:onClick="click" android:text="-" android:textColor="#000000" android:textSize="25sp" android:textStyle="italic" /> <Button android:id="@+id/btn1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_marginTop="20dp" android:layout_toLeftOf="@+id/btn2" android:gravity="center" android:onClick="click" android:text="+" android:textColor="#000000" android:textSize="25sp" android:textStyle="italic" /> </RelativeLayout>
package com.example.jsj; import android.os.Bundle; import android.app.Activity; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void click(View v) { TextView tv2 = (TextView) findViewById(R.id.tv2); EditText et1 = (EditText) findViewById(R.id.et1); EditText et2 = (EditText) findViewById(R.id.et2); double num1,num2,result=0; num1=Integer.parseInt(et1.getText().toString()); num2=Integer.parseInt(et2.getText().toString()); switch (v.getId()) { case R.id.btn1: result=num1+num2; break; case R.id.btn2: result=num1-num2; break; case R.id.btn3: result=num1*num2; break; case R.id.btn4: result=num1/num2; break; } tv2.setText(result+""); } }