startActivityForResult与onActivityResult

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：

 

点击搜索按钮，找到DianXin。

 

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);