Question

我正在使用recyclerView在listitems中显示我的navigation drawer。我已经实施了onclickListener，但我一直坚持如何打开另一个activity 1}} 项为clicked时。截至目前，根据代码，我的所有项目都会在项目点击时显示，toast显示item position。

我很感激帮助。

AdapterClass.java

＆＃13;

public class AdapterClass extends RecyclerView.Adapter<AdapterClass.MyViewHolder> {
    private LayoutInflater inflater;
    private Context context;
List<Information>data= Collections.emptyList();
    public AdapterClass(Context context,List<Information>data){
        this.context=context;

        inflater= LayoutInflater.from(context);
        this.data=data;
    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
       View view= inflater.inflate(R.layout.custom_row,parent,false);
        MyViewHolder holder=new MyViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        Information current=data.get(position);
        holder.title.setText(current.title);
        holder.icon.setImageResource(current.iconId);

    }

    @Override
    public int getItemCount() {
        return data.size();
    }
    class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        TextView title;
        ImageView icon;

        public MyViewHolder(View itemView) {
            super(itemView);
            title=(TextView)itemView.findViewById(R.id.listText);
           icon=(ImageView)itemView.findViewById(R.id.listIcon);
            itemView.setClickable(true);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {

            Toast.makeText(context,"The Item Clicked is: "+getPosition(),Toast.LENGTH_SHORT).show();
        }
    };
}

＆＃13;

Log  cat error after implementing Konrad's solution

    02-27 15:24:52.833: D/AndroidRuntime(1630): --------- beginning of crash
02-27 15:24:52.834: E/AndroidRuntime(1630): FATAL EXCEPTION: main
02-27 15:24:52.834: E/AndroidRuntime(1630): Process: com.snappy.stevekamau.snappy, PID: 1630
02-27 15:24:52.834: E/AndroidRuntime(1630): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.snappy.stevekamau.snappy/com.snappy.stevekamau.snappy.YourActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()' on a null object reference
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.ActivityThread.access$800(ActivityThread.java:144)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.os.Handler.dispatchMessage(Handler.java:102)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.os.Looper.loop(Looper.java:135)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.ActivityThread.main(ActivityThread.java:5221)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at java.lang.reflect.Method.invoke(Native Method)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at java.lang.reflect.Method.invoke(Method.java:372)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
02-27 15:24:52.834: E/AndroidRuntime(1630): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()' on a null object reference
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.support.v7.internal.widget.ToolbarWidgetWrapper.<init>(ToolbarWidgetWrapper.java:95)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.support.v7.internal.widget.ToolbarWidgetWrapper.<init>(ToolbarWidgetWrapper.java:88)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.support.v7.internal.app.ToolbarActionBar.<init>(ToolbarActionBar.java:84)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.support.v7.app.ActionBarActivityDelegateBase.setSupportActionBar(ActionBarActivityDelegateBase.java:175)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.support.v7.app.ActionBarActivity.setSupportActionBar(ActionBarActivity.java:92)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at com.snappy.stevekamau.snappy.YourActivity.onCreate(YourActivity.java:18)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.Activity.performCreate(Activity.java:5933)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
02-27 15:24:52.834: E/AndroidRuntime(1630):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
02-27 15:24:52.834: E/AndroidRuntime(1630):     ... 10 more
02-27 15:24:52.839: W/ActivityManager(464):   Force finishing activity com.snappy.stevekamau.snappy/.YourActivity
02-27 15:24:52.841: W/ActivityManager(464):   Force finishing activity com.snappy.stevekamau.snappy/.MainActivity

Answer 1

您可以（但不需要，因为ViewHolder类不是静态的）创建字段上下文，如下所示：

private final Context context;

public MyViewHolder(View itemView) {
    super(itemView);
    context = itemView.getContext();
    ...
}

并在您的onClick方法上调用如下所示：

@Override
public void onClick(View v) {          

    final Intent intent;
    switch (getAdapterPostion()){
        case 0:
           intent =  new Intent(context, FirstActivity.class);
           break;

        case 1:
            intent =  new Intent(context, SecondActivity.class);
            break;
           ...
        default:
           intent =  new Intent(context, DefaultActivity.class);
           break;
     }
    context.startActivity(intent);
}

或

@Override
public void onClick(View v) {          

    final Intent intent;
    if (getAdapterPosition() == sth){
       intent =  new Intent(context, OneActivity.class);
    } else if (getPosition() == sth2){
       intent =  new Intent(context, SecondActivity.class);
    } else {
       intent =  new Intent(context, DifferentActivity.class);
    }
    context.startActivity(intent);
}

Answer 2

您可以实现适配器的onClickListener：

  public class AdapterClass extends RecyclerView.Adapter<AdapterClass.MyViewHolder>implements View.OnClickListener

并使用其中的方法接口

public interface mClickListener {
    public void mClick(View v, int position);
}

并在你的onClick方法中调用界面中的方法并将其传递给视图和位置

在您的主要活动中实现该界面

public class MainActivity extends ActionBarActivity implements AdapterClass.mClickListener

并覆盖该方法

@Override
public void onCommentsClick(View v, int position) {
    final Intent intent = new Intent(this, OtherActivity.class);
}

最好通过活动而不是其他类来管理您的活动转换

Answer 3

很久以前就问过这个问题，无论如何，我会写一个简单的答案，可能对某人有帮助。

将clickListener附加到RecyclerView项目的最简单方法是在Adapter中，如下所示：

public class MyAdapter extends RecyclerView.Adapter<AdapterClass.MyViewHolder> {

....

@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
    holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(view.getContext(), YourActivity.Class);
                startActivity(intent);
            }
        });
}

Answer 4

简单地说，您可以轻松完成......您只需在此处查看您的活动背景。

//Create intent getting the context of your View and the class where you want to go
Intent intent = new Intent(view.getContext(), YourClass.class);

//start the activity from the view/context
view.getContext().startActivity(intent); //If you are inside activity, otherwise pass context to this funtion

请记住，您需要修改AndroidManifest.xml并放置活动...

<activity
        android:name=".YourClass"
        android:label="Label for your activity"></activity>

Answer 5

示例，在 MyRecyclerViewAdapter 中添加方法：

public interface ItemClickListener {
   void onItemClick(View view, int position);
}

在 MainActivity.java

中

@Override
public void onItemClick(View view, int position) {
Context context=view.getContext();
Intent intent=new Intent();
switch (position){
    case 0:
        intent =  new Intent(context, ChildActivity.class);
        context.startActivity(intent);
        break;
   }
}

Answer 6

在将Glide用于ImageView时或在recyclerview中将intent用于项目onClick时，在声明上下文时发生问题。我发现这对我有用，可以帮助我声明要在Glide，Intent或Toast中使用的上下文。

public class NoteAdapter extends FirestoreRecyclerAdapter<Note,NoteAdapter.NoteHolder> {

Context context;

public NoteAdapter(@NonNull FirestoreRecyclerOptions<Note> options) {
    super(options);
}

@Override
protected void onBindViewHolder(@NonNull NoteHolder holder, int position, @NonNull Note model) {
    holder.r_tv.setText(model.getTitle());
    Glide.with(CategoryActivity.context).load(model.getImage()).into(holder.r_iv);

    context = holder.itemView.getContext();

    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(context, SuggestActivity.class);
            context.startActivity(i);
        }
    });

}

@NonNull
@Override
public NoteHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_category,parent,false);

    return new NoteHolder(v);
}

public static class NoteHolder extends RecyclerView.ViewHolder
{
    TextView r_tv;
    ImageView r_iv;

    public NoteHolder(@NonNull View itemView) {
        super(itemView);

        r_tv = itemView.findViewById(R.id.r_tv);
        r_iv = itemView.findViewById(R.id.r_iv);


    }
}
}

Answer 7

public class AdapterClass extends RecyclerView.Adapter<AdapterClass.MyViewHolder> {
    private LayoutInflater inflater;
    private Context context;
List<Information>data= Collections.emptyList();
    public AdapterClass(Context context,List<Information>data){
        this.context=context;

        inflater= LayoutInflater.from(context);
        this.data=data;
    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
       View view= inflater.inflate(R.layout.custom_row,parent,false);
        MyViewHolder holder=new MyViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        Information current=data.get(position);
        holder.title.setText(current.title);
        holder.icon.setImageResource(current.iconId);

    }

    @Override
    public int getItemCount() {
        return data.size();
    }
    class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        TextView title;
        ImageView icon;

        public MyViewHolder(View itemView) {
            super(itemView);
            title=(TextView)itemView.findViewById(R.id.listText);
           icon=(ImageView)itemView.findViewById(R.id.listIcon);
            itemView.setClickable(true);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {

            Toast.makeText(context,"The Item Clicked is: "+getPosition(),Toast.LENGTH_SHORT).show();
        }
    };
}

public class AdapterClass extends RecyclerView.Adapter<AdapterClass.MyViewHolder> {
    private LayoutInflater inflater;
    private Context context;
List<Information>data= Collections.emptyList();
    public AdapterClass(Context context,List<Information>data){
        this.context=context;

        inflater= LayoutInflater.from(context);
        this.data=data;
    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
       View view= inflater.inflate(R.layout.custom_row,parent,false);
        MyViewHolder holder=new MyViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        Information current=data.get(position);
        holder.title.setText(current.title);
        holder.icon.setImageResource(current.iconId);

    }

    @Override
    public int getItemCount() {
        return data.size();
    }
    class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        TextView title;
        ImageView icon;

        public MyViewHolder(View itemView) {
            super(itemView);
            title=(TextView)itemView.findViewById(R.id.listText);
           icon=(ImageView)itemView.findViewById(R.id.listIcon);
            itemView.setClickable(true);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {

            Toast.makeText(context,"The Item Clicked is: "+getPosition(),Toast.LENGTH_SHORT).show();
        }
    };
}

Answer 8

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ViewHolder> {
private ArrayList<Android> android;
Context context;
private ImageView img;
public DataAdapter(Context contextN, ArrayList<Android> android) {
    this.android = android;
    this.context=contextN;
}

@Override
public DataAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.adapter_list, viewGroup, false);
    return new ViewHolder(view);
}

@Override
public void onBindViewHolder(DataAdapter.ViewHolder viewHolder, int i) {

    viewHolder.tv_name.setText(android.get(i).getOffer());
    viewHolder.tv_version.setText(android.get(i).getOfferType());
    Picasso.with(context).load(android.get(i).getImg()).transform(new CircleTransform()).into(img);

}

@Override
public int getItemCount() {
    return android.size();
}

public class ViewHolder extends RecyclerView.ViewHolder{
    private TextView tv_name,tv_version,tv_api_level;

    public ViewHolder(View view) {
        super(view);

        tv_name = (TextView)view.findViewById(R.id.tv_name);
        tv_version = (TextView)view.findViewById(R.id.tv_version);
        img = (ImageView) view.findViewById(R.id.img);

                context = itemView.getContext();

                itemView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {

                        int itemPosition = getLayoutPosition();
                        Toast.makeText(context, "" + itemPosition, Toast.LENGTH_SHORT).show();
                        Intent intent = new Intent(context,Show.class);
                        intent.putExtra("name",""+android.get(itemPosition).getOffer());
                        intent.putExtra("img",""+android.get(itemPosition).getImg());
                        context.startActivity(intent);

            }
        });
    }
}
}

Answer 9

这个问题很早以前就被问到了，但是尽管Milad Moosavi`s answer非常接近，但以上答案都没有帮助我。要从“回收者”视图上的特定位置打开新活动，以下代码可能会有所帮助：


    @Override
    public void onBindViewHolder(@NonNull TripViewHolder holder, int position) {
        Trip currentTrip = trips.get(position);

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(v.getContext(), EditTrip.class);
                v.getContext().startActivity(intent);
            }
        });

        holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                Intent intent = new Intent(v.getContext(), ReadTripActivity.class);
                v.getContext().startActivity(intent);

                return false;
            }
        });
    }

Answer 10

iconView =（ImageView）itemLayoutView .findViewById（R.id.iconId）;

        itemLayoutView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent intent = new Intent(v.getContext(), SecondPage.class);
                v.getContext().startActivity(intent);
                Toast.makeText(v.getContext(), "os version is: " + feed.getTitle(), Toast.LENGTH_SHORT).show();
            }
        });

如何在recyclerView项目onclick上打开不同的活动

10 个答案: