java - PagerAdapter 中的 ImageButton onclick。需要转到另一个类/XML 文件。错误

Question

对此进行了一段时间的研究，但似乎找不到任何解决方案。我有 5 张采用 PagerLayout 滑动格式的图像。我想要做的是单击图像后，我想要转到另一个 XML 文件/类。

代码:(我已经注释掉了我尝试过的方法。)

public class CustomSwipeAdapter extends PagerAdapter {
    Context context;
    private int[] image_resources = {R.drawable.chestpress,R.drawable.deadlift,R.drawable.squat,R.drawable.pullups,R.drawable.dips};
    private Context ctx; //Gets the context of a current state or application. Tells program what is going on somewhere else.
    private LayoutInflater layoutInflater;  //USed to instantiate layout XML files to View Objct.
    private LayoutInflater inflater;
    private String[] names = {"Dumbell Press","Deadlift","Squats","Pullups","Tricep Dips"};
    public ImageView imageView;
    Activity activity;
    View views = null;


    public CustomSwipeAdapter(Context ctx){
        this.ctx = ctx;
    }


    @Override
    public int getCount() {
        return image_resources.length;
    }

    @Override
    public boolean isViewFromObject(View view, Object o) {
        return view==(LinearLayout)o;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        inflater = (LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        layoutInflater = (LayoutInflater)ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View item_view = layoutInflater.inflate(R.layout.swipe_layout,container,false);
        imageView = (ImageView)item_view.findViewById(R.id.image_view);
        TextView textView = (TextView)item_view.findViewById(R.id.image_count);
        imageView.setImageResource(image_resources[position]);
        textView.setText(names[position]);
        container.addView(item_view);


        imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(position == 0) {
                    Log.d("Exercise","Dumbell Press");
                    //Intent intent = new Intent(ctx,MyActivity.class);
                    //Intent intent = new Intent(CustomSwipeAdapter.this,MyActivity.class);
                    //Intent intent = new Intent(context,MyActivity.class);
                    //views = inflater.inflate(R.layout.main,null);
                    //context.startActivity(intent);
                    //MyActivity koo = new MyActivity(); (Tried just instantiating another class (Im so lost) 

                }
                if(position == 1){
                    Log.d("Exercise","Deadlift!");
                }
                if(position == 2){
                    Log.d("Exercise","Squats");
                }
            }
        });

        return item_view;
    }




    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((LinearLayout)object);
    }
}

非常新的 android/java 程序员。感谢您的阅读。

Answer 1

试试这个:

Intent intent = new Intent(CustomSwipeAdapter.this.ctx, MyActivity.class);
CustomSwipeAdapter.this.ctx.startActivity(intent);

还要确保将正确的上下文传递给您的适配器构造函数。您将传递的上下文可以是 Activity 本身。

因此，在您的 Activity 上，当您需要创建新适配器时，请执行以下操作:

CustomSwipeAdapter myAdapter = new CustomSwipeAdapter(this);

其中 this 是您要在其上创建适配器的 Activity 。如果您需要在 fragment 内创建适配器，只需使用以下命令获取 Activity :

MyFragment.getActivity();

最后，如果您想知道:“为什么这有效？它需要一个上下文，而我正在传递一个 Activity !”。

这是一个简短的答案:

Activity inherits context. Thus, if you are in an activity, you only need to pass itself to use the context. It also contains a pointer to getBaseContext(). You might occasionally need to reference that, if you need the entire application context, but most likely you won't for a while.

希望这有帮助。如果您遇到更多错误，请告诉我(不要忘记发布您的 logcat，以便我们可以更好地帮助您)。