Android - Intent - 传递数据

1. 主叫Activity向被叫Activity传递数据：

（1）主叫Activity写数据：

Intent intent = new Intent(action);
intent.putExtra("key", "value");
startActivity(intent);

（2）被叫Activity读数据：

Intent intent = getIntent();
String strFromCaller = intent.getStringExtra("key");

2. 被叫Activity向主叫Activity放回数据：

（1）主叫Activity以startActivityForResult()方式启动被叫Activity：

Intent intent = new Intent();
intent.setClass(getApplicationContext(), NewAcitvity.class);
// START_NEWACTIVITY is a predefined constant to identify the Activity invoked by this intent.
startActivityForResult(intent, START_NEWACTIVITY);

（2）被叫Activity写数据：

Uri uri = Uri.parse("back info");
Intent data = new Intent(null, uri);
data.putExtra("key", "value");
setResult(Activity.RESULT_OK, data);

（3）主叫Activity读数据：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
	super.onActivityResult(requestCode, resultCode, data);
	switch (requestCode)
	{
		case START_NEWACTIVITY:
			if (resultCode == Activity.RESULT_OK)
			{
				Toast.makeText(this, data.getStringExtra("key"), Toast.LENGTH_LONG).show();
//				Toast.makeText(this, data.getData().toString(), Toast.LENGTH_LONG).show();
			}
			break;
	}
}