使用Sniffer Pro监控网络流量

android Activity之间的跳转不只是有startActivity(Intent i)的,startActivityForResult(Intent intent, int requestCode)也是常用的

方法。

在一个主界面(主Activity)上能连接往许多不同子功能模块(子Activity上去)，当子模块的事情做完之后就回到主界面，或许还同时返回一些子模块完成的数据交给主Activity处理。这个时候就要用到回调函数onActivityResult()。

需要注意三个方法：startActivityForResult(Intent intent, int requestCode)，onActivityResult(int requestCode, int resultCode, Intent data)，setResult(int resultCode, Intent data).

例如如下代码：从From跳转至ToB和ToC

From：

if(条件){

Intent intent = new Intent(this, ToB.class);

startActivityForResult(intent, REQUEST_CODE_01);//跳转至ToB

}else{

Intent intent = new Intent(this, ToC.class);

startActivityForResult(intent, REQUEST_CODE_02);//跳转至ToC

}

public void onActivityResult(int requestCode, int resultCode, Intent data){

switch (requestCode) {//请求标记

case REQUEST_CODE_01:

if(resultCode==Activity.RESULT_OK)

//do something

break;

case REQUEST_CODE_02:

//do something

break;

}

}

startActivityForResult(Intent intent, int requestCode)的参数，需要注意的是第二个，我们用的是REQUEST_CODE_01和REQUEST_CODE_02，其实这个是我们自己定义的一个int型常量，用于标记的，具体作用可在onActivityResult方法里看到，用于判断是哪个Activity传来的。

requestCode是请求标记, resultCode是返回标记。

ToB：

Intent intent = new Intent();

intent.putExtra(key, value);

setResult(Activity.RESULT_OK, intent);

finish();//结束之后会将结果传回From

这里的跳转回去，只能用setResult(int resultCode, Intent data)方法，否则会出错，无法从onActivityResult(int requestCode, int resultCode, Intent data)中的data接收到传回来的数据。

ToC：

Intent intent = new Intent();

intent.putExtra(key, value);

setResult(Activity.RESULT_OK, intent);

finish();//结束之后会将结果传回From

setResult的第一个参数对应上面onActivityResult的第二个参数。

实例的一个效果：





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源码：

<?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/mTextView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="我的联系人" />
<EditText
android:id="@+id/mEditText01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="姓名"
/>
<EditText
android:id="@+id/mEditText02"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="电话号码"
/>
<Button
android:id="@+id/mButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="搜索"
/>
</LinearLayout>

package com.xc.ex05_10;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class EX05_10 extends Activity {
private TextView mTextView;
private Button mButton;
private EditText mEditText01;
private EditText mEditText02;
//回传标志
private static final int PICK_CONTACT_SUBACTIVITY = 2;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

mTextView = (TextView)findViewById(R.id.mTextView);
mEditText01 = (EditText)findViewById(R.id.mEditText01);
mEditText02 = (EditText)findViewById(R.id.mEditText02);
mButton = (Button)findViewById(R.id.mButton);

mButton.setOnClickListener(new Button.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
startActivityForResult(new Intent(Intent.ACTION_PICK,
android.provider.ContactsContract.Contacts.CONTENT_URI),
PICK_CONTACT_SUBACTIVITY);
}
});

}
//向新打开的Activity传递参数
//resultCode为回传的标记
//data为B(新打开的Activity)中回传的Intent
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
try{
switch (requestCode) {
case PICK_CONTACT_SUBACTIVITY:
final Uri uriRet = data.getData();
if(uriRet != null){
try{
//必须要有android.permission.READ_CONTACTS权限
Cursor c = managedQuery(uriRet, null, null, null, null);
c.moveToFirst();
String strName = c.getString(c.getColumnIndexOrThrow(ContactsContract.Contacts.DISPLAY_NAME));
mEditText01.setText(strName);
//取得联系人的电话
int contactId = c.getInt(c.getColumnIndexOrThrow(ContactsContract.Contacts._ID));
Cursor phones = getContentResolver().query(
ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
null,
ContactsContract.CommonDataKinds.Phone.CONTACT_ID + " = "+ contactId,
null, null);
StringBuffer sb = new StringBuffer();
int typePhone, resType;
String numPhone;
if(phones.getCount() > 0){
phones.moveToFirst();
typePhone = phones.getInt(
phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.TYPE));
numPhone = phones.getString(
phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
resType = ContactsContract.CommonDataKinds.Phone.getTypeLabelResource(typePhone);
sb.append(getString(resType) + ":" + numPhone + "\n");
mEditText02.setText(numPhone);
}else {
sb.append("no Phone number found");
}
Toast.makeText
(this, sb.toString(), Toast.LENGTH_SHORT).show();
}catch (Exception e) {
mTextView.setText(e.toString());
e.printStackTrace();
}
}
break;
default:
break;
}
}catch (Exception e) {
e.printStackTrace();
}
super.onActivityResult(requestCode, resultCode, data);
}
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.xc.ex05_10"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.READ_CONTACTS"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=".EX05_10" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

</manifest>

例子②：

布局文件为两个按钮，不再给出。

package com.example.intentproject;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class SenderActivity extends Activity{

private static final int MY_REQUEST_CODE = 1;
private Button sender;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sender);
sender = (Button)findViewById(R.id.sender);

sender.setOnClickListener(new Button.OnClickListener() {

@Override
public void onClick(View v) {
Intent intent = new Intent(SenderActivity.this, RecieverActivity.class);
startActivityForResult(intent, MY_REQUEST_CODE);
}
});
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch(requestCode){
case MY_REQUEST_CODE:
// 取出数据
String info=data.getStringExtra("data2");
Toast.makeText(this, info, Toast.LENGTH_LONG).show();
break;
}
switch (resultCode) {
case Activity.RESULT_CANCELED:
Toast.makeText(this, "处理："+String.valueOf(Activity.RESULT_CANCELED), Toast.LENGTH_LONG).show();
break;
case Activity.RESULT_OK:
Toast.makeText(this, "处理："+String.valueOf(Activity.RESULT_OK), Toast.LENGTH_LONG).show();
break;
case Activity.RESULT_FIRST_USER:
String info=data.getStringExtra("data2");
Toast.makeText(this, info, Toast.LENGTH_LONG).show();
break;

default:
break;
}
super.onActivityResult(requestCode, resultCode, data);
}
}

package com.example.intentproject;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;

public class RecieverActivity extends Activity{

private Button reciever;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.reciever);
reciever = (Button)findViewById(R.id.reciever);

Intent intent = new Intent();
intent.putExtra("data2", "给你回送数据！礼尚往来！");
this.setResult(Activity.RESULT_FIRST_USER, intent);
}
}

RecieverActivity.java中也可以写成：

Intent intent=this.getIntent();
//返回数据
intent.putExtra("data2", "给你回送数据！礼尚往来！");
this.setResult(Activity.RESULT_FIRST_USER, intent);

也可以在SenderActivity.java文件中一开始就传递参数，在按钮响应事件中写成：

sender.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {

Intent intent = new Intent(SenderActivity.this,
ReciverActivity.class);
intent.putExtra("data", "给你发送数据！");
// 这种启动方式 ，表示是有返回结果的
SenderActivity.this.startActivityForResult(intent,
MY_REQUEST_CODE);
}
});

RecieverActivity.java中写：

Intent intent=this.getIntent();
String info=intent.getStringExtra("data");
Toast.makeText(this, info, Toast.LENGTH_LONG).show();
//返回数据
intent.putExtra("data2", "给你回送数据！礼尚往来！");
this.setResult(Activity.RESULT_FIRST_USER, intent);

本文出自 “千寻” 博客，请务必保留此出处http://5200415.blog.51cto.com/3851969/969821