问题
I am trying to use a Button in an AlertDialog to view a webpage.
The problem is that this AlertDialog is located inside a class that extends ItemizedOverlay and doesn't extend Activity, so Eclipse underlines it and gives the following error:
The method startActivity() is undefined for the type new DialogInterface.OnClickListener(){}
I would like to launch activities from the PositiveButton, NeutralButton and NegativeButton, but I am not able to.
In case you need more context, the main Activity is a MapView with some ItemizedOverlay, and I would like to launch a webpage with directions or another activity that does that.
回答1:
Construct a constructor in the class which contains your alert with Context object as a parameter. Assign it to a Context variable.
Use this context variable for creating the intent.
Intent intent = new Intent(mContext, "Your next activity to be shown");//mContext is the Context variable over here.
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
mContext.startActivity(intent);
回答2:
Actually the answer is provided by you in your question. i.e startActivity is undefined in ClickListener functions. so in oncreate function, initialize a Global variable like
Activity myActivity = this;
then in onclicklistener, start another activity from this.
myActivity.startActivity(xxxxxxxx);
This could be one answer.
回答3:
Take a look at this
In these you write your desired code inside the Positive Button,You can start an Activity by using Intent..
startActivity(new Intent (YouPage.this,NewPage.class));
回答4:
Pass context of the activity in constructor of that class and create a field of type activity and store context in that activity and then
say
Activity activityClass;
and initialize it from your constructor
and start activity from that activiytClass
activityClass.startActivity();
回答5:
If you have the context say context.startActivity();
if you dont have context try to get it from getContext(); or getApplicationContext(); or getBaseContext();
来源：https://stackoverflow.com/questions/5297687/android-startactivity-from-alertdialog