如何从另一个活动发送/检测对特定活动的引用/标志
如何从另一个活动发送/检测对特定活动的引用/标志
提问于 2019-06-20 08:03:58
如果某个特定的Activity是从另一个Activity启动的，我如何发送或检测引用或标志？我实际上需要一种表单，在这种表单中，只有当特定的Activity调用某段代码时，我才能执行这段代码，例如：
练习1:
Intent intent = new Intent(this,ranking.class);
startActivity(intent);Activity2:
Intent intent = new Intent(this,ranking.class);
startActivity(intent);Ranking.class (这是伪代码，因为我真的不知道该怎么做/做什么)
if(I was called by Activity 1) {
//do something
} else {
finish();
}回答 2
Stack Overflow用户
回答已采纳
发布于 2019-06-20 08:22:32
你可以通过.putExtra向你的Intent发送一条消息。
练习1
Intent intent = new Intent(this,ranking.class);
intent.putExtra("activity", 1);
startActivity(intent);练习2
Intent intent = new Intent(this,ranking.class);
intent.putExtra("activity", 2);
startActivity(intent);Ranking.class
Intent intent = getIntent();
int activityNumber = intent.getIntExtra("activity", 0);
if (activityNumber == 1) {
//do something
} else{
finish();
}Stack Overflow用户
发布于 2019-06-20 17:39:11
@以色列-德拉-克鲁兹的答案是正确的，你需要使用extra来区分旗帜。这里的版本更紧凑，避免使用幻数和幻键
public class RankingActivity extends Activity {
private static final ACTIVITY_OPTION_KEY = "activityOptionKey";
private static final int FROM_ACTIVITY_ONE = 1;
private static final int FROM_ACTIVITY_TWO = 2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_rating);
...
Bundle bundle = getIntent().getExtra();
int option = bundle.getInt(ACTIVITY_OPTION_KEY);
if(option == FROM_ACTIVITY_ONE) {
// do something when called from activity one
} else if(option == FROM_ACTIVITY_TWO) {
// do something when called from activity two
} else {
// is there something else?
}
...
}
// Use intent factory to remove dependency to magic number and magic key
public static Intent createIntentFromActivityOne(Activity activity) {
Intent intent = new Intent(activity, RatingActivity.class);
intent.putExtra(ACTIVITY_OPTION_KEY, FROM_ACTIVITY_ONE);
return intent;
}
public static Intent createIntentFromActivityTwo(Activity activity) {
Intent intent = new Intent(activity, RatingActivity.class);
intent.putExtra(ACTIVITY_OPTION_KEY, FROM_ACTIVITY_TWO);
return intent;
}
}然后，您可以在不知道RatingActivity魔术密钥和魔术数字的情况下创建意图：
// from activity one
Intent intent = RatingActivity.createIntentFromActivityOne(this);
startActivity(intent);
// from activity two
Intent intent = RatingActivity.createIntentFromActivityTwo(this);
startActivity(intent);页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/56677378
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