第一个入门小程序加法器

MainActivity:
 1 package com.example.plus;
 2 
 3 import android.app.Activity;
 4 import android.content.Intent;
 5 import android.os.Bundle;
 6 import android.view.View;
 7 import android.widget.Button;
 8 import android.widget.EditText;
 9 import android.widget.TextView;
10 
11 public class MainActivity extends Activity {
12 
13     private Button Count;
14     private EditText Plus1;
15     private EditText Plus2;
16 
17     protected void onCreate(Bundle savedInstanceState) {
18         super.onCreate(savedInstanceState);
19         setContentView(R.layout.activity_main);
20 
21         Plus1 = (EditText) findViewById(R.id.plusone);
22         Plus2 = (EditText) findViewById(R.id.plustwo);
23 
24         Count = (Button) findViewById(R.id.count);
25         Count.setText("Count");
26 
27         TextView SymbolPlus = (TextView) findViewById(R.id.symbol);
28         SymbolPlus.setText(R.string.symbol);
29 
30         Count.setOnClickListener(new View.OnClickListener() {
31 
32             @Override
33             public void onClick(View arg0) {
34                 String Plus1str = Plus1.getText().toString();
35                 String Plus2str = Plus2.getText().toString();
36 
37                 // 把控件的值放到Intent的Extra里面
38                 Intent ToResult = new Intent();
39                 ToResult.putExtra("one", Plus1str);
40                 ToResult.putExtra("two", Plus2str);
41 
42                 ToResult.setClass(MainActivity.this, Result.class);
43                 MainActivity.this.startActivity(ToResult);
44 
45             }
46         });
47     }
48 }

Resule:

 1 package com.example.plus;
 2 
 3 import android.os.Bundle;
 4 import android.widget.TextView;
 5 import android.app.Activity;
 6 import android.content.Intent;
 7 
 8 public class Result extends Activity {
 9     private TextView answer;
10 
11     protected void onCreate(Bundle savedInstanceState) {
12         super.onCreate(savedInstanceState);
13         setContentView(R.layout.result);
14 
15         answer = (TextView) findViewById(R.id.Answer);
16 
17         Intent intent = getIntent();
18 
19         String Plus1 = intent.getStringExtra("one");
20         String Plus2 = intent.getStringExtra("two");
21 
22         int num1 = Integer.parseInt(Plus1);
23         int num2 = Integer.parseInt(Plus2);
24 
25         int result = num1 + num2;
26 
27         answer.setText(result + "");
28     }
29 }

Main.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="fill_parent"
 5     android:layout_height="fill_parent"
 6     android:orientation="vertical"
 7     tools:context=".MainActivity" >
 8 
 9     <EditText
10         android:id="@+id/plusone"
11         android:layout_width="fill_parent"
12         android:layout_height="wrap_content"
13         android:inputType="none" />
14 
15     <TextView
16         android:id="@+id/symbol"
17         android:layout_width="fill_parent"
18         android:layout_height="wrap_content" />
19 
20     <EditText
21         android:id="@+id/plustwo"
22         android:layout_width="fill_parent"
23         android:layout_height="wrap_content"
24         android:inputType="none" />
25 
26     <Button
27         android:id="@+id/count"
28         android:layout_width="fill_parent"
29         android:layout_height="wrap_content" />
30 
31 </LinearLayout>