Android的 - 两个活动之间传递数据得到的NullPointerException [英] Android - Pass Data Between Two Activities get NullPointerException
问题描述
我有3个活动,我们将称他们为A,B和C. A和B都具有发送视图C.上一架C来自不同的事情发生基于C的活动意图和设计。我通过这样的数据从A到C:
意向意图=新的意图(这一点,C.class);
intent.putExtra(行动,A);
startActivity(意向);
则在C的onCreate方法,我有这样的事情:
捆绑额外= getIntent()getExtras()。
如果(extras.getString(行动)。等于(A)){
//做一点事
}
然后,我从B到C我有
意向意图=新的意图(这一点,C.class);
startActivity(意向);
然后,我得到了NullPointerException异常,我猜这是因为我还没有specifed一个字符串行动,从B到C下。
现在我只需要添加一行B在此情况下,但是,如果有更多的活动,或一个大的项目,这将不会是很好的,因为对于每个活动去一个我需要这个。
我如何才能拥有它,所以我不无添加行动蜇到b活动得到这个例外?
感谢您提前帮助。
修改
如果我有这样的从A到C
意向意图=新的意图(这一点,C.class);
intent.putExtra(行动,A);
intent.putExtra(措施2,A);
startActivity(意向);
这从B到C
意向意图=新的意图(这一点,C.class);
intent.putExtra(行动,B);
startActivity(意向);
和那么这在C的onCreate从B到C下失败:
捆绑额外= getIntent()getExtras()。
如果(临时演员!= NULL){
如果(extras.getString(行动)。等于(A)){
//做一点事
}
否则,如果(extras.getString(措施2)。等于(A)){
// DO Stuuf
}
}
更改code在C级这样的检查束为空或不是。</ P>
捆绑额外= getIntent()getExtras()。
如果(临时演员!= NULL){
如果(extras.getString(行动)!= NULL)
如果(extras.getString(行动)。等于(A)){
//做一点事
}
}
如果(extras.getString(措施2)!= NULL)
如果(extras.getString(措施2)。等于(A2)){
//做一点事
}
}
}
I have 3 activities we will call them A, B and C. A and B both have intents that send the view to C. And design on which one C came from different things happen on C's activity. I pass the data like this from A to C:
Intent intent = new Intent(this, C.class);
intent.putExtra("Action", "A");
startActivity(intent);
Then in C's onCreate method I have something like this:
Bundle extras = getIntent().getExtras();
if (extras.getString("Action").equals("A")) {
//DO SOMETHING
}
Then I from B to C I have
Intent intent = new Intent(this, C.class);
startActivity(intent);
And then I get the NullPointerException, I am guessing this is because i have not specifed a String "Action" when going from B to C.
Now I could just add one line for B in this case but, if there were for more activities or a large project this would not be good, because for each activity going to one I would need this.
How can I have it so I don't get this exception without adding an "Action" sting to activity B?
Thanks for the help in advance.
EDIT
If I have this from A to C
Intent intent = new Intent(this, C.class);
intent.putExtra("Action", "A");
intent.putExtra("Action2", "A");
startActivity(intent);
And this from B to C
Intent intent = new Intent(this, C.class);
intent.putExtra("Action", "B");
startActivity(intent);
And then this in onCreate of C it fails when going from B to C:
Bundle extras = getIntent().getExtras();
if (extras != null) {
if (extras.getString("Action").equals("A")) {
//DO SOMETHING
}
else if (extras.getString("Action2").equals("A")) {
//DO Stuuf
}
}
Change the code in C class like this for checking the bundle is null or not.
Bundle extras = getIntent().getExtras();
if(extras != null){
if(extras.getString("Action") != null)
if (extras.getString("Action").equals("A")) {
//DO SOMETHING
}
}
if(extras.getString("Action2") != null)
if (extras.getString("Action2").equals("A2")) {
//DO SOMETHING
}
}
}
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