Android开发：向下一个activity传递数据，返回数据给上一个activity

1.向下一个activity传递数据

activity1

         Button button=(Button) findViewById(R.id.button1);
         button.setOnClickListener(new OnClickListener() {

             @Override
             public void onClick(View v) {
                 Intent intent=new Intent("1111111111111111111");
                 intent.addCategory("android.intent.category.MY_CATEGORY");
                 intent.putExtra("aaa", "this is a message");
                 startActivityForResult(intent, 0x11);
             }
         });

activity2

1         Intent intent=getIntent();
         String data=intent.getStringExtra("aaa");
         Toast.makeText(activity2.this, data, Toast.LENGTH_SHORT).show();

2.返回数据给上一个activity

activity2，按钮实现返回到activity1

         Button jumpButton=(Button) findViewById(R.id.jumpButton);
         jumpButton.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 Intent intent=new Intent();
                 intent.putExtra("xxx", "This is second activity data!");
                 setResult(RESULT_OK,intent);
                 finish();
             }
         });

activity1

重写onActivityResult()

     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         super.onActivityResult(requestCode, resultCode, data);
           if (requestCode==0x11) {
             if (resultCode==RESULT_OK) {
                  returnData=data.getStringExtra("xxx");
             }
         }
     }