Activity（2. 跳转）

Activity的跳转有两种方式：

• 普通跳转：

Intent intent = new Intent(MainActivity.this, SecondActivty.class);
startActivity(intent);

• 带返回值的跳转：
  • 调用startActivityForResult，参数带请求索引

public static final int REQUEST_SEC = 1; //请求的ID

Intent backIntent = new Intent(MainActivity.this, SecondActivty.class);
startActivityForResult(backIntent, REQUEST_SEC);

• • 接收端Activity处理该跳转请求

Intent intent = new Intent();
intent.putExtra("value", "hello word");
intent.putExtra("input", MainActivity.REQUEST_SEC);
setResult(RESULT_BACK,intent);
finish();//返回前调用finish，销毁本activity,类似于back

• • 在MainActivity中处理返回

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
        
        Log.i(TAG_ACTIVITY, "requestCode:" + requestCode);
        Log.i(TAG_ACTIVITY, "resultCode:"  + resultCode);
        
        if(resultCode == SecondActivty.RESULT_BACK && REQUEST_SEC == requestCode){
            Toast.makeText(getApplicationContext(), data.getStringExtra("value"),
                     Toast.LENGTH_SHORT).show();
        }
    }