从非活动类开始新的活动

Question

I know it's been alot of questions like this, but I didn't find the answer.

What I have:

1. A GridView + a ButtonAdapter class, which also has a OnClickListener class to get wich button on the GridView in pressed. (you can see the basic structure here : http://www.stealthcopter.com/blog/2010/09/android-creating-a-custom-adapter-for-gridview-buttonadapter/ )

What I need:

I need to start a new Activity from my OnClickListener class. As I know I can make it only in my main acitivity class(or other class which extends Activity ), but this is what I really need. I know only this structure:

Intent i = new Intent(MyMain.this, MyNewActivity.class)
startActivity(i);

I want to be able to use this structure from my OnClickListener class.

Answer 1

In your ButtonAdapter constructor pass the context of the Activity where you build the adapter and then use that Context to start the new Activity .

Edit: Following that tutorial when you build your adapter you will do something like this:

ButtonAdapter adapter = new ButtonAdapter(this);// this is the activity(if you create in an activity the adapter)

The Context that you get in the constructor of your ButtonAdapter you will pass it to your OnClickListener :

    class MyOnClickListener implements OnClickListener  
    {  
     private final int position;  
private Context ctx;

     public MyOnClickListener(int position, Context ctx)  
     {  
      this.position = position;  
this.ctx = ctx;
     }  

     public void onClick(View v)  
     {  
      // Preform a function based on the position  
      someFunction(this.position)  
      Intent i = new Intent(MyMain.this, MyNewActivity.class)
ctx.startActivity(i);
     }  
    }  

and use it like this:

btn.setOnClickListener(new MyOnClickListener(position, mContext));

Answer 2

由于MyOnClickListener.onClick（）中有View对象，因此可以简单地使用View.getContext（）（http://developer.android.com/reference/android/view/View.html#getContext（））来获取上下文对象并开始另一个活动。