Android中的TextView 、EditText、Activity、Intent实例小计算器

正在学习Android，都不知道怎么下手，希望高手给点建议，有什么好的教程分享，小弟感谢不尽。以下小实例主要功能是实现Activity的跳转

主要方法：

（1）intent.putExtra("add1", one);//把one的值加到add1 中

（2）intent.setClass(firstActivity.this, secondActivity.class);//实现跳转

 （3）firstActivity.this.startActivityForResult(intent, REQUEST_CODE);//返回成功的参数

（4）protected void onActivityResult(int requestCode, int resultCode, Intent data) {//回调函数
  super.onActivityResult(requestCode, resultCode, data){
      }
 }

（5）public boolean onCreateOptionsMenu(Menu menu) {//创建菜单
  // TODO Auto-generated method stub
  menu.add(0, 1, 1, R.string.exit);
  return super.onCreateOptionsMenu(menu);
 }

（6）public boolean onMenuItemSelected(int featureId, MenuItem item) {//监听选中菜单项
    return super.onMenuItemSelected(featureId, item);
 }

（7）Intent intent =getIntent();//获取Intent的对象

(8)String one = intent.getStringExtra("add1");//获取参数的值

java代码:

firstActivity.java

package com.test;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class firstActivity extends Activity {     public static final int REQUEST_CODE = 1; EditText add1,add2;    Button btn1;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        //实例化组件        add1 = (EditText) findViewById(R.id.add1);        add2 = (EditText) findViewById(R.id.add2);        btn1 = (Button) findViewById(R.id.Calculator);        //设置监听器        btn1.setOnClickListener(new operator());    }    //新建一个类实现监听器    class operator implements OnClickListener{  @Override  public void onClick(View v) {   //获取文本框的值    String one = add1.getText().toString();   String two = add2.getText().toString();      //使用Intent对数据的封装   Intent intent  = new Intent();   intent.putExtra("add1", one);   intent.putExtra("add2", two);   intent.setClass(firstActivity.this, secondActivity.class);      firstActivity.this.startActivityForResult(intent, REQUEST_CODE);     }          } //返回 方法 protected void onActivityResult(int requestCode, int resultCode, Intent data) {  super.onActivityResult(requestCode, resultCode, data);  if(requestCode==1){      if(resultCode==secondActivity.RESULT_CODE){       String str=data.getStringExtra("back");       Toast.makeText(this, str, Toast.LENGTH_LONG).show();       }     } } //菜单方法 @Override public boolean onCreateOptionsMenu(Menu menu) {  // TODO Auto-generated method stub  menu.add(0, 1, 1, R.string.exit);  menu.add(1, 2, 2, R.string.abort);  return super.onCreateOptionsMenu(menu); } //选中菜单方法 @Override public boolean onMenuItemSelected(int featureId, MenuItem item) {  if(item.getItemId()==1){   Toast.makeText(this, "退出成功",Toast.LENGTH_LONG).show();   finish();  }  if(item.getItemId()==2){   Toast.makeText(this, "关于",Toast.LENGTH_LONG).show();  }  return super.onMenuItemSelected(featureId, item); }  }

*******

secondActivity.java

 

package com.test;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;public class secondActivity  extends Activity{    TextView result;    Button btn2;    public final static int RESULT_CODE=1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);    setContentView(R.layout.result);//实例化组件result = (TextView) findViewById(R.id.returnresult);btn2 = (Button) findViewById(R.id.result);//通过Intent获取数据Intent intent =getIntent();String one = intent.getStringExtra("add1");String two = intent.getStringExtra("add2");int add1 =Integer.parseInt(one);int add2 = Integer.parseInt(two);int result1 = add1*add2;result.setText(result1+"");btn2.setOnClickListener(new test());}class test implements OnClickListener{@Overridepublic void onClick(View v) {// TODO Auto-generated method stubIntent intent=new Intent();intent.putExtra("back", "你可以重新计算了！");setResult(RESULT_CODE, intent);finish();   }}}

***********

布局文件

.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="android程序测试" />    <LinearLayout         xmlns:android="http://schemas.android.com/apk/res/android"        android:orientation="vertical"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        >                <EditText             android:id="@+id/add1"            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:hint="请入第一个数字"            />        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="x"></TextView>        <EditText            android:id="@+id/add2"            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:hint="请请输入第二个数字">        </EditText>                <Button            android:id="@+id/Calculator"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:gravity="center"            android:text="计算结果">                 </Button>    </LinearLayout>  </LinearLayout>

返回结果

result.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <TextView        android:id="@+id/returnresult"        android:layout_width="fill_parent"        android:layout_height="wrap_content"></TextView>        <Button        android:id="@+id/result"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="返回"></Button></LinearLayout>

string.xml文件

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="hello">Hello World, FriendActivity!</string>    <string name="app_name">Friend</string>    <string name="test">android</string>    <string name="exit">退出</string>    <string name="abort">关于</string></resources>

运行结果