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");
            }
        }  
    }