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();
             }
         });
     }

 }

Username.java

 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"));
     }

 }

Finish.java

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