Question

并提前感谢您的建议。

MainActivity.java

RecyclerView.Adapter mAdapter;
@Override
...
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);    

    mRecyclerView = (RecyclerView) findViewById(R.id.RecyclerView);

    mAdapter = new MyAdapter(getBaseContext(),TITLES,ICONS,NAME,EMAIL,PROFILE);

    mRecyclerView.setAdapter(mAdapter);
    mLayoutManager = new LinearLayoutManager(this);       
    mRecyclerView.setLayoutManager(mLayoutManager);
...}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    Bitmap bitmap   = null;
    String path = "";
    mImageCaptureUri = data.getData();
    path = getPath(mImageCaptureUri); //from Gallery

    if (path == null)
        path = mImageCaptureUri.getPath();
    if (path != null)
        bitmap  = BitmapFactory.decodeFile(path);
    mImageView.setImageBitmap(bitmap);
}

Myadapter.java

class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
...
Context mContext;
Activity mActivity;
private static final int SELECT_PICTURE = 1;
private String selectedImagePath;

public static class ViewHolder extends RecyclerView.ViewHolder {...}

MyAdapter(Context context, String Titles[],int Icons[],String Name,String Email, int Profile){
    this.mContext = context;
    mNavTitles = Titles
    mIcons = Icons;
    name = Name;
    email = Email;
    profile = Profile;
}

@Override
public void onBindViewHolder(MyAdapter.ViewHolder holder, int position) {
    if(holder.Holderid ==1) {                              
        holder.textView.setText(mNavTitles[position - 1]); 
        holder.imageView.setImageResource(mIcons[position -1]);
    }
    else{
        holder.profile.setImageResource(profile);           
        holder.Name.setText(name);
        holder.email.setText(email);
        holder.profile.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mActivity = (Activity)mContext;
                Intent imageIntent = new Intent();
                imageIntent.setType("image/*");
                imageIntent.setAction(imageIntent.ACTION_GET_CONTENT);
                mActivity.startActivityForResult(Intent.createChooser(imageIntent, "Select photo"), 2);
            }
        });

    }
}

可以在适配器中调用startActivityForResult吗？为什么错误出现在mActivity = (Activity)mContext;？

p.s。：我试图创建方法 public void startxx(Intent i){ startActivityForResult(i, 2); } 并在适配器中调用它...但适配器需要statxx static和Activity非静态。

Answer 1

Context是Activity的基类。你不能在Java中转发对象。这就是为什么你不能执行mActivity = (Activity)mContext;。

您不能从Adapter类调用startActivityForResult（），因为它是Activity.java类的方法。这是您可以尝试的一种解决方案 - - 声明一个接口。说IObserver.java

public interface IObserver {

    // change signature of method as per your need
    public abstract void onItemClicked();
    }
}

在Adapter类中写一个方法说

public void setListener（IObserver obs）{ mObserver = obs; }
在Activity类中实现IObserver接口。您还需要实现onItemClicked（）方法。
从onCreate（）活动方法，调用adapter.setListener(this);
在适配器类中，从onClick（）方法，编写如下代码

holder.profile.setOnClickListener(new View.OnClickListener() {
            @Override 
            public void onClick(View v) {
               // It will call method from activity class where you can do startActivityForResult()
               mObserver.onItemClicked();
            } 
        });

希望它会有所帮助。

我在适配器中使用上下文时出错，我想在适配器中使用startActivityForResult（...），我该怎么办？

1 个答案: