Android -- Activity接收另一个Activity返回的数据

当我们在一个A（Activity）跳转到另外一个B（Activity）时，再由B返回A时，A如何接受返回的数据。

我们在B页面加了一个输入框和按钮，当输入数据，点击按钮返回信息到A页面，先来看B页面Activity代码

package com.example.testapp;

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

public class BMainActivity extends Activity {

    private TextView t;
    private EditText t1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bmain);
        t = (TextView) findViewById(R.id.tv);
        Intent i = getIntent();
        // User user = (User) i.getSerializableExtra("user");
        User user = (User) i.getParcelableExtra("user");
        t.setText("name=" + user.getName() + ",age=" + user.getAge());

        t1 = (EditText) findViewById(R.id.editText1);
        findViewById(R.id.button1).setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent i = new Intent();
                i.putExtra("data", t1.getText().toString());
                setResult(1, i);
                finish();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.bmain, menu);
        return true;
    }

}

代码中为按钮增加一个事件，并使用setResult方法返回Intent对象，然后调用finish方法

点击按钮后返回到A页面（这个按钮是如何定位上一个页面的还在调研…）
A的Activity代码如下

package com.example.testapp;

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

public class AMainActivity extends Activity {

    private EditText editText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_amain);

        editText = (EditText) findViewById(R.id.editText1);

        findViewById(R.id.button1).setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Intent i = new Intent(AMainActivity.this,
                                BMainActivity.class);
                        i.putExtra("user", new User("lijingwei", 25));
//                      startActivity(i);
                        startActivityForResult(i, 0);
                    }
                });
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data){
        super.onActivityResult(requestCode, resultCode, data);

        editText.setText(data.getStringExtra("data"));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.amain, menu);
        return true;
    }

}

注意，我们将startActivity(i)改成了startActivityForResult(i,0)，并且重写了protected void onActivityResult(int requestCode, int resultCode, Intent data)方法。用来接收B返回的数据。