Intent

btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //能夠經過全局上下文/或者MainActivity.this,直接使用this會指向btn1
//                Intent i = new Intent(MainActivity.this,SecondActivity.class);
                Intent intent = new Intent(mContext,SecondActivity.class);
                startActivity(intent);
            }
        });

        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //回傳結果的跳轉
                Intent intent = new Intent(mContext,ThirdActivity.class);
                startActivityForResult(intent,RequestCode);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == RequestCode && resultCode == ResultCode){
            tv = (TextView)findViewById(R.id.textView);
            String content = data.getStringExtra("data");
            tv.setText(content);
        }
    }




        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.putExtra("data",Content);
                //代理方法,回傳值
                setResult(ResultCode,intent);
                //銷燬當前acitivity
                finish();
            }
        });