Android分步注册，Activity由B返回A修改再前往B，B中已填项不变

某日突然想到标题问题，一般来说返回上一个Activity，当前Activity应该自动销毁。要想保留值，便想到用bundle传递的方式

最后功能是实现了，但感觉方法很笨。

主要代码如下：

package com.example.valuepass;

import com.example.programdemo.R;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;


public class MainActivity extends Activity {
    private EditText et_phonenumber;
    private Button bt_next;
    private int ACTIVITY1 = 1;
    private int USERNAME = 2;
    private Bundle bundle = new Bundle();
    private Intent intent = new Intent();
    private String TAG = "MainActivity";
    private String username;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_phonenumber = (EditText) findViewById(R.id.et_phonenumber);
        bt_next = (Button) findViewById(R.id.bt_next);
        
        bt_next.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v){
                bundle.putString("phonenumber", et_phonenumber.getText().toString());
                Log.v(TAG,et_phonenumber.getText().toString());
                bundle.putString("username", username);
                intent.putExtras(bundle);
                intent.setClass(MainActivity.this,Username.class);
                startActivityForResult(intent,ACTIVITY1);  
            }    
        });     
    }
    
    @Override
    protected void onActivityResult(int requestCode,int resultCode,Intent data){
        if(requestCode == ACTIVITY1){
            if(resultCode == USERNAME){
                Bundle getbundle;
                getbundle = data.getExtras();
                username = getbundle.getString("username");
                Log.v(TAG,username);
            }
        }
        super.onActivityResult(requestCode, resultCode, data);
    }
 
}

package com.example.valuepass;

import com.example.programdemo.R;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Username extends Activity{
    private TextView et_phonenumber;
    private EditText et_username;
    private Button bt_next;
    private Button bt_back;
    private Bundle bundle = new Bundle();
    private Intent intent = new Intent();
    private int USERNAME = 2;
    private String TAG = "Username";
    
    @Override
    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.username);
        et_phonenumber = (TextView)findViewById(R.id.et_phonenumber);
        et_username = (EditText)findViewById(R.id.et_username);
        bt_next = (Button)findViewById(R.id.bt_next);
        bt_back = (Button)findViewById(R.id.bt_back);
        bundle = this.getIntent().getExtras();
        Log.v(TAG,bundle.getString("phonenumber"));
        et_phonenumber.setText(bundle.getString("phonenumber"));
        et_username.setText(bundle.getString("username"));
        
        bt_next.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v){
                 bundle.putString("username", et_username.getText().toString());
                 intent.putExtras(bundle);
                 intent.setClass(Username.this,Finish.class);
                 startActivity(intent);
            }
        });
        
        bt_back.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v){
                Bundle bundle_back = new Bundle();
                bundle_back.putString("username", et_username.getText().toString());
                Log.v(TAG,bundle_back.getString("username"));
                intent.putExtras(bundle_back);
                setResult(USERNAME,intent);
                onBackPressed();
            }
        });
    }

}

package com.example.valuepass;

import com.example.programdemo.R;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class Finish extends Activity{
    private TextView et_phonenumber;
    private TextView et_username;
    private Bundle bundle = new Bundle();
    @Override
    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.finish);
        
        bundle = this.getIntent().getExtras();
        et_phonenumber = (TextView)findViewById(R.id.et_phonenumber);
        et_username = (TextView)findViewById(R.id.et_username);
        et_phonenumber.setText(bundle.getString("phonenumber"));
        et_username.setText(bundle.getString("username"));
    }

}

 PS：后来在网上看到类似问题，有人回答：

加flag启动activity
Intent.FLAG_ACTIVITY_REORDER_TO_FRONT这个标志表示：如果这个activity已经启动了，就不产生新的activity，而只是把这个activity实例加到栈顶来就可以了。

打算有时间试一下。不过似乎要改onBackPressed();

代码下载