如何在 recyclerView 項目上打開不同的活動 onclick

Question

我使用的是recyclerView展示我listitems的navigation drawer 。我已經實現了onclickListener但我一直卡在如何打開一個不同的activity都項目時， clicked 。 根據代碼，我的所有項目現在都在項目點擊時顯示item position的toast 。

我將不勝感激。

適配器類.java

 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(); } }; }

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，因為ViewHolder類不是靜態的）創建字段上下文，如下所示：

private final Context context;

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

並在您的onClick方法上調用以下方法：

@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);
}

或者

@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

很簡單，您可以輕松完成……您只需要在此處從您的視圖中獲取您的活動的上下文。

//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

請記住，您需要修改 AndroidManifest.xml 並將活動...

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

Answer 3

您可以實現適配器的 onClickListener：

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

並使用帶有方法的接口

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

並在您的 onClick 方法中調用接口中的方法並將視圖和位置傳遞給它

在您的主要活動中實現該接口

public class MainActivity extends ActionBarActivity implements AdapterClass.mClickListener

並覆蓋該方法

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

因為最好通過活動而不是其他課程來管理您的活動過渡

Answer 4

很久以前就有人問過這個問題，無論如何我會寫一個簡單的答案可能對某人有所幫助。

將 clickListener 附加到 RecyclerView 項目的最簡單方法是在適配器內，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 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

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 7

問題發生在聲明上下文中，同時為 ImageView 使用 Glide 或在 recyclerview 中為 item onClick 使用 Intent。 我發現這對我有用，這有助於我聲明要在 Glide 或 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 8

 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 9

很久以前就有人問過這個問題，但上面的答案都沒有幫助我，盡管Milad Moosavi 的答案非常接近。 要從回收器視圖的某個位置打開一個新活動，以下代碼可能會有所幫助：

    @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();
            }
        });