Android将数据返回到以前的活动

我需要您的帮助：在完成当前活动之前，我想将额外的数据放入上一个活动

活动A开始活动B 当我完成活动B时，我希望在活动A中输入新数据

我怎么能做到？

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在此之前，非常感谢使用

startActivityforResult

打开活动B。然后在活动A中覆盖活动Y结果（int，int，Intent）

例如：

public class MyActivity extends Activity {
 ...

 static final int PICK_CONTACT_REQUEST = 0;

 protected boolean onKeyDown(int keyCode, KeyEvent event) {
     if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
         // When the user center presses, let them pick a contact.
         startActivityForResult(
             new Intent(Intent.ACTION_PICK,
             new Uri("content://contacts")),
             PICK_CONTACT_REQUEST);
        return true;
     }
     return false;
 }

 protected void onActivityResult(int requestCode, int resultCode,
         Intent data) {
     if (requestCode == PICK_CONTACT_REQUEST) {
         if (resultCode == RESULT_OK) {
             // A contact was picked.  Here we will just display it
             // to the user.
             startActivity(new Intent(Intent.ACTION_VIEW, data));
         }
     }
 }
}

public class ActivityA extends Activity {

static final int REQUEST_CODE = 0;

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        setContentView(R.layout.xyz);

        DateBtn.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                    startActivityForResult(new Intent(ActivityA.this,ActivityB.class), REQUEST_CODE);
                }
            });
    }

 protected void onActivityResult(int requestCode, int resultCode,
         Intent data) {
     if (requestCode == REQUEST_CODE) {
         if (resultCode == RESULT_OK) {
             // A contact was picked.  Here we will just display it
             // to the user.
             startActivity(new Intent(Intent.ACTION_VIEW, data));
         }
     }
 }
}


public class ActivityB extends Activity {

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        setContentView(R.layout.xyz);

        BackBtn.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
            Intent intent = new Intent();
            intent.putExtra("DATA", "your string");
            setResult(RESULT_OK, intent);
            finish();
                }
            });
    }

}

---

检查Android SDK解释，最好是问答+示例。

使用startActivityforResult启动活动B。在活动A中实现对ActivityResult（int，int，Intent）方法的覆盖，并在活动B中实现setResult

例如：

public class MyActivity extends Activity {
 ...

 static final int PICK_CONTACT_REQUEST = 0;

 protected boolean onKeyDown(int keyCode, KeyEvent event) {
     if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
         // When the user center presses, let them pick a contact.
         startActivityForResult(
             new Intent(Intent.ACTION_PICK,
             new Uri("content://contacts")),
             PICK_CONTACT_REQUEST);
        return true;
     }
     return false;
 }

 protected void onActivityResult(int requestCode, int resultCode,
         Intent data) {
     if (requestCode == PICK_CONTACT_REQUEST) {
         if (resultCode == RESULT_OK) {
             // A contact was picked.  Here we will just display it
             // to the user.
             startActivity(new Intent(Intent.ACTION_VIEW, data));
         }
     }
 }
}

public class ActivityA extends Activity {

static final int REQUEST_CODE = 0;

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        setContentView(R.layout.xyz);

        DateBtn.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                    startActivityForResult(new Intent(ActivityA.this,ActivityB.class), REQUEST_CODE);
                }
            });
    }

 protected void onActivityResult(int requestCode, int resultCode,
         Intent data) {
     if (requestCode == REQUEST_CODE) {
         if (resultCode == RESULT_OK) {
             // A contact was picked.  Here we will just display it
             // to the user.
             startActivity(new Intent(Intent.ACTION_VIEW, data));
         }
     }
 }
}


public class ActivityB extends Activity {

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        setContentView(R.layout.xyz);

        BackBtn.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
            Intent intent = new Intent();
            intent.putExtra("DATA", "your string");
            setResult(RESULT_OK, intent);
            finish();
                }
            });
    }

}

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在活动A中使用startActivityforResult启动活动B，并在活动A中使用@override onActivityResult（int，int，Intent）方法从活动B获取数据。