[转]startActivityForResult的用法和demo

有时候我们需要把A activity提交数据给B  activity处理，然后把结果返回给A

这种方式在很多种情况需要用到，比如我应用的程序需要有拍照上传的功能。

一种解决方案是  我的应用程序 〉调用系统相机〉拍照〉关闭系统相机〉返回拍照后的照片到我的应用程序

启动一个ForResult的意图：

Intent intent = new Intent(MainAcitvity.this,
      RequestActivity.class);
    //发送意图标示为REQUSET=1
    startActivityForResult(intent, REQUSET);

B Activity处理数据：

Intent intent=new Intent();

intent.putExtra(KEY_USER_ID, et01.getText().toString());
    intent.putExtra(KEY_USER_PASSWORD, et02.getText().toString());
setResult(RESULT_OK, intent);
 finish();

那么startActivityForResult如何使用呢：

package com.cn.activityresult.demo;  

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 MainAcitvity extends Activity {  

    private Button btn01;
    private TextView tv01;
    public static final int REQUSET = 1;  

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
        //requestCode标示请求的标示   resultCode表示有数据
        if (requestCode == MainAcitvity.REQUSET && resultCode == RESULT_OK) {
            String str = "账号"
                    + data.getStringExtra(RequestActivity.KEY_USER_ID) + "\n"
                    + "密码"
                    + data.getStringExtra(RequestActivity.KEY_USER_PASSWORD);
            tv01.setText(str);
        }
        Toast.makeText(
                this,
                "requestCode=" + requestCode + ":" + "resultCode=" + resultCode,
                Toast.LENGTH_LONG).show();
    }  

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn01 = (Button) findViewById(R.id.btn01);
        tv01 = (TextView) findViewById(R.id.tv01);
        btn01.setOnClickListener(new OnClickListener() {  

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent intent = new Intent(MainAcitvity.this,
                        RequestActivity.class);
                //发送意图标示为REQUSET=1
                startActivityForResult(intent, REQUSET);
            }
        });  

    }
}  

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;  

public class RequestActivity extends Activity {  

    private Button btn01;
    private EditText et01;
    private EditText et02;
    public static final String KEY_USER_ID="KEY_USER_ID";
    public static final String KEY_USER_PASSWORD="KEY_USER_PASSWORD";  

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.request_activity);
        btn01=(Button)findViewById(R.id.btn01);
        et01=(EditText)findViewById(R.id.et01);
        et02=(EditText)findViewById(R.id.et02);  

        btn01.setOnClickListener(new OnClickListener() {  

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent intent=new Intent();
                intent.putExtra(KEY_USER_ID, et01.getText().toString());
                intent.putExtra(KEY_USER_PASSWORD, et02.getText().toString());
                setResult(RESULT_OK, intent);
                finish(); //此处一定要调用finish（）
            }
        });
    }
}