关于这个已经有很多问题了，我觉得我的代码应该可以工作。我想要做的是活动 A 启动活动 B，发送一个意图。Activity B 然后为结果启动 Activity A，应该会收到一个新的 Intent。我的代码在下面，根据下面文档中的引用，代码应该可以工作：
“标准”和“singleTop”模式仅在一个方面彼此不同：每次“标准”活动有新的意图时，都会创建一个新的类实例来响应该意图。每个实例 > 处理一个意图。类似地，也可以创建“singleTop”活动的新实例来处理新意图。但是，如果目标任务>已经在其堆栈顶部有一个现有的活动实例，>该实例将接收新意图（在 onNewIntent() 调用中）；没有创建新的 >instance。
所以基于此，我的代码如下： PS我的 onNewIntent(Intent) 没有被调用，我想知道我是否把它放在正确的类中。
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drink_sale_list);
mListView = (ListView) findViewById(R.id.list);
mDrinksAdapter = new drinksAdapter(getApplicationContext(), drinks, drinkPics);
mListView.setAdapter(mDrinksAdapter);
mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//If the bn!= null, this means that this activity was started by Activity B via startActivityForResult()
Bundle bn = getIntent().getExtras();
if(bn != null){
Intent intent = new Intent();
Bundle bundle = new Bundle();
bundle.putSerializable("anotherDrinkObject", drinks.get(position));
intent.putExtras(bundle);
intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
setResult(RESULT_OK, intent);
finish();
}
else {
Intent intent = new Intent(drinkSaleList.this, SaleActivity.class);
Bundle bundle = new Bundle();
bundle.putSerializable("DrinkObject", drinks.get(position));
intent.putExtras(bundle);
startActivity(intent);
}
}
});
}
}
活动 B
public class SaleActivity extends AppCompatActivity {
private ListView mListView;
private drinksAdapter mDrinksAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_sale);
setContentView(R.layout.activity_sale);
Bundle bundle = getIntent().getExtras();
Drink drink = (Drink) bundle.getSerializable("DrinkObject");
mListView = (ListView) findViewById(R.id.saleList);
mDrinksAdapter = new drinksAdapter(getApplicationContext(), drink);
mListView.setAdapter(mDrinksAdapter);
Button addDrink = (Button) findViewById(R.id.addAnotherDrink);
addDrink.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(SaleActivity.this, drinkSaleList.class);
intent.removeExtra("DrinkObject");
intent.putExtra("anotherDrink", true);
startActivityForResult(intent, 1);
}
});
}
@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
setIntent(intent);//must store the new intent unless getIntent() will return the old one
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) {
if (resultCode == RESULT_OK) {
Bundle bn = getIntent().getExtras();
Drink drink = (Drink) bn.getSerializable("anotherDrinkObject");
mDrinksAdapter.add(drink);
}
}
}
}