学步园

看mars的视频，写了一个乘法计算，只要涉及到多个Activity的通信问题，现总结如下：

多个activity的通信靠的是Intent(Aanroid提供的避免多组建耦合的一个消息机制，翻译叫意图)

基本通信原理如下：

另外罗列下Intent几个比较重要的方法

getIntent()-----创建一个Intent;

putExtra()------发送Intent消息内容

getExtra(String name, Object defaultValue)---得到Intent消息内容

setClass(activity_01,activity_02)----设置互相通信对象

现在上代码：

package com.android.test_001.button;

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.EditText;
import android.widget.TextView;

public class buttonActivity extends Activity {
/** Called when the activity is first created. */
private EditText factorOne,factorTwo;
private TextView symbol_x;
private Button caculate_x;
    @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        factorOne=(EditText)findViewById(R.id.fanctorOne);
        factorTwo=(EditText)findViewById(R.id.fanctorTow);
        symbol_x=(TextView)findViewById(R.id.symbol_x);
        caculate_x=(Button)findViewById(R.id.caculate);

//symbol_x.setText(R.string.symbol_x);
        caculate_x.setText(R.string.caculate_x);

        caculate_x.setOnClickListener(new OnClickListener(){

            @Override
public void onClick(View v) {
// TODO Auto-generated method stub
                String factorOneValue=factorOne.getText().toString();
                String factorTwoValue=factorTwo.getText().toString();
                Intent intent=getIntent();
                intent.putExtra("factorOne", factorOneValue);
                intent.putExtra("factorTwo", factorTwoValue);
                intent.setClass(buttonActivity.this, resultActivity.class);
                buttonActivity.this.startActivity(intent);
            }

        });
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.test_001.button"
    android:versionCode="1"
    android:versionName="1.0" >

<uses-sdk android:minSdkVersion="4" />

<application
android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
<activity
android:label="@string/app_name"
            android:name=".hellowordActivity" >

</activity>
<activity
android:label="@string/caculate"
             android:name=".buttonActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:label="@string/result"
             android:name=".resultActivity" >
</activity>

</application>

</manifest>

package com.android.test_001.button;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

public class resultActivity extends Activity{


/* (non-Javadoc)
     * @see android.app.Activity#onOptionsItemSelected(android.view.MenuItem)
*/
    @Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
        if(item.getItemId()==1){
            finish();
        }
return super.onOptionsItemSelected(item);
    }
/* (non-Javadoc)
     * @see android.app.Activity#onCreateOptionsMenu(android.view.Menu)
*/
    @Override
public boolean onCreateOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
        menu.add(0, 1, 1, R.string.exit);
        menu.add(0, 2, 2, R.string.about);
return super.onCreateOptionsMenu(menu);

    }


/* (non-Javadoc)
     * @see android.app.Activity#onCreate(android.os.Bundle)
*/
private TextView resultText;
    @Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.result);
        resultText=(TextView)findViewById(R.id.result);
        Intent intent=getIntent();
        String factorOne =intent.getStringExtra("factorOne");
        String factorTow =intent.getStringExtra("factorTwo");
//System.out.println("f1="+factorOne+"/f2="+factorTow);
        int intfactorOne=Integer.parseInt(factorOne);
int intfactorTow =Integer.parseInt(factorTow);
int result=intfactorOne*intfactorTow;
        resultText.setText(result+"");
    }


}

<?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"
    android:background="@drawable/pic1">


<TextView
android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />
<TextView
android:id="@+id/myXmlHello"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/myhello"/>
<TextView
android:id="@+id/myjavahello"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/myurllink_01"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/myurllink_02"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
/>
<EditText
android:id="@+id/fanctorOne"
         android:layout_width="fill_parent"
        android:layout_height="wrap_content"
/>
<EditText
android:id="@+id/fanctorTow"
         android:layout_width="fill_parent"
        android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/symbol_x"
         android:layout_width="fill_parent"
        android:layout_height="wrap_content"
/>
<Button
android:id="@+id/caculate"
        android:layout_width="100px"
        android:layout_height="50px"
/>


</LinearLayout>

<?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"
    android:background="@drawable/pic1">

<TextView
android:id="@+id/result"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
/>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<resources>

<string name="hello">my first_smm helloword app</string>
<string name="app_name">Hi smm i miss you</string>
<string name="myhello">my first hello for android-this is defined by xml</string>
<string name="symbol_x">X</string>
<string name="caculate_x">计算</string>   
<string name="caculate">乘法计算</string>    
<string name="result">计算</string>  
<string name="exit">退出</string>
<string name="about">关于</string>
<color name="red">#FF0000</color>

</resources>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.test_001.button"
    android:versionCode="1"
    android:versionName="1.0" >

<uses-sdk android:minSdkVersion="4" />

<application
android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
<activity
android:label="@string/app_name"
            android:name=".hellowordActivity" >

</activity>
<activity
android:label="@string/caculate"
             android:name=".buttonActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:label="@string/result"
             android:name=".resultActivity" >
</activity>

</application>

</manifest>

我在做的过程中碰到许多问题：

1、因为多个Activity的话，要再androidManifest.xml里面注册，而我注册的时候写错了：

       <activity
             android:label="@string/caculate"
             android:name=".buttonActivity.java" >
             <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
红色部分写错了，不应该有.java，报的是logcat报的错误是NotFoundClassException error

2、在buttonActivity.java里面一定要加一下语句：

buttonActivity.this.startActivity(intent);

启动消息发送

其他的都是一些小问题，不再仔细讲解了，基本功太差，还是得多练

结果图：