返回数据到前一个activity

在主程序中 调用activity2的方法改为startActivityForResult（intent，0） 0代表下一个Activity要返回值的依据，可指定为自行定义的参考标示符。程序重写onactivityresult（）这个方法，使程序在收到result后，重写加载写回原先输入的值。（在AS中重写结果报错，我删去了@override）

activity主程序的代码

package com.administrator.testall;

import android.os.Bundle;
import android.provider.MediaStore;
import android.support.v7.app.ActionBarActivity;
import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;

public class ChangeTest01 extends ActionBarActivity {

    private EditText et;
    private RadioButton rg1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_change_test01);

        Button button01 = (Button) findViewById(R.id.button1);
        button01.setOnClickListener(new Button.OnClickListener()
        {
                                       public void onClick(View v)
                                       {
                                           EditText et = (EditText) findViewById(R.id.editText1);
                                           double editText1 = Double.parseDouble(et.getText().toString()); //取值

                                           String choose = "";
                                           RadioButton rg1 = (RadioButton) findViewById(R.id.radioButton); //取复选框值
                                           if(rg1.isClickable())
                                           {
                                               choose = "M";
                                           }
                                           else choose = "F";

                                           Intent intent = new Intent();
                                           intent.setClass(ChangeTest01.this,ChangeTest02.class); //activity却换

                                           Bundle bundle = new Bundle();  //activity的数据传递
                                           bundle.putDouble("edit1",editText1); //引号内为传递数据，引号后面为传递值
                                           bundle.putString("choose",choose);

                                           intent.putExtras(bundle); //将bundle对象分配给intert；
                                           startActivityForResult(intent, 0);    //调用另一个activity
                                       }
                                    }
        );
    }

    protected void OnActivityResult(int requestCode,int resultCode,Intent data)
    {
        switch (resultCode)
        {
            case RESULT_OK:
                //取得来自activity2的数据 显示在画面上
                Bundle bundle = data.getExtras();
                String choose = bundle.getString("choose");
                double edit1 = bundle.getDouble("edit1");;

                et.setText(String.valueOf(edit1));
                if(choose.equals("M")) rg1.setChecked(true);
                break;
            default:
                break;
        }
    }
}

注意 这里不需要使用@Override重写

activity2的代码如下

package com.administrator.testall;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.widget.Button;
import android.widget.TextView;
import android.view.View;

public class ChangeTest02 extends ActionBarActivity {

    Bundle bundle;
    Intent intent;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_change_test02);

        intent = this.getIntent();
        bundle = this.getIntent().getExtras(); //取得intent中的bundle对象

        String choose = bundle.getString("choose"); //取得bundle对象中的数据
        double edit1 = bundle.getDouble("edit1");

        String chooseText = "";
        if(choose.equals("M"))
        {
            chooseText="A";
        }else chooseText="B";

        TextView textView1 = (TextView) findViewById(R.id.textView1);
        textView1.setText(chooseText);
        TextView textView2 = (TextView) findViewById(R.id.textView2);
        textView2.setText(String.valueOf(edit1)); //double转string

        Button button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(new Button.OnClickListener()
        {
                                      public void onClick(View v)
                                      {
                                          ChangeTest02.this.setResult(RESULT_OK,intent); //返回result到上一个activity
                                          ChangeTest02.this.finish();  //结束这个activity
                                      }
                                   }
        );
    }

}