startActivityForResult和startActivity的區別是一個是帶值傳輸，一個是直接跳轉

具體用法如下：

activity_main：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="進入" />

</RelativeLayout>
 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
<EditText
    android:id="@+id/text1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:hint="輸入數字"
    
    />
<Button 
    android:id="@+id/finish"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="反回"
    
    />
</LinearLayout>
 

package com.example.demo1;

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

public class MainActivity extends Activity {
private TextView textview;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		findViewById(R.id.bt).setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				startActivityForResult(new Intent(MainActivity.this,
						SecondActivity.class), 1);
			}
		});
		textview=(TextView) findViewById(R.id.textview);
	}

	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		// TODO Auto-generated method stub
		super.onActivityResult(requestCode, resultCode, data);
		if (requestCode == 1 && resultCode == 4) {
			String s=data.getStringExtra("bian");
			textview.setText(s);
		}
	}

}
 

package com.example.demo1;

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 SecondActivity extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
	// TODO Auto-generated method stub
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main1);
	final EditText text1=(EditText) findViewById(R.id.text1);
	Button finish=(Button) findViewById(R.id.finish);
	finish.setOnClickListener(new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			Intent i=new Intent();
			i.putExtra("bian", text1.getText().toString());
			setResult(4,i);
			finish();
		}
	});
}
}

  <activity  android:name="com.example.demo1.SecondActivity"></activity>