Android 如何在适配器中启动活动

我试图做的是在我的适配器中启动一个活动，但我的另一个适配器上似乎出现了一个错误

java.lang.ClassCastException:com.lim.fiture.fiture.models.ProgramTracker不能强制转换为com.lim.fiture.fiture.models.ProgramExecute

my

DayExerciseAdapter

上的错误点只包含两个内容；exerciseName和exerciseReps

这是我的DayExerciseAdapter这就是错误所在

公共类DayExerciseAdapter扩展了RecyclerView.Adapter{
私人语境；
私人ArrayList程序练习；
public DayExerciseAdapter（上下文、ArrayList程序练习）{
this.context=上下文；
this.programExercises=programExercises；
}
@凌驾
public ViewHolder onCreateViewHolder（视图组父级，int-viewType）{
View View=LayoutInflater.from（parent.getContext（））.flate（R.layout.day\u exercise\u layout\u item，parent，false）；
ViewHolder ViewHolder=新的ViewHolder（视图）；
返回视图持有者；
}
@凌驾
公共无效onBindViewHolder（ViewHolder，int位置）{
holder.exerciseName.setText（programmexercises.get（position.getExerciseName（）.toUpperCase（））；
holder.exerciseReps.setText（String.valueOf（programmexercises.get（position.getReps（））；
}
@凌驾
public int getItemCount（）{
返回programExercises.size（）；
}
公共类ViewHolder扩展了RecyclerView.ViewHolder{
text查看exerciseName、exerciseReps、doneTxt；
公共视图持有者（视图项视图）{
超级（项目视图）；
exerciseName=itemView.findViewById（R.id.exerciseName）；
exerciseReps=itemView.findviewbyd（R.id.exerciseReps）；
doneTxt=itemView.findviewbyd（R.id.doneTxt）；
}
}
}

这是我开始我的活动意图的地方

public class UserProgramWeekAdapter extends RecyclerView.Adapter<UserProgramWeekAdapter.ViewHolder> {

private Context context;
private ArrayList<ProgramTrackerWrapper> programTrackers;


public UserProgramWeekAdapter(Context context, ArrayList<ProgramTrackerWrapper> programTrackers) {
    this.context = context;
    this.programTrackers = programTrackers;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_user_program_week_adapter, parent, false);
    ViewHolder viewHolder = new ViewHolder(view);
    return viewHolder;

}

@Override
public void onBindViewHolder(UserProgramWeekAdapter.ViewHolder holder, int position) {
    Log.d("UserProgramWeekAdapter", "Day: " + programTrackers.get(position).getDay());
    Log.d("UserProgramWeekAdapter", "Size: " + programTrackers.get(position).getProgramTrackers().size());
    holder.dayTxt.setText(programTrackers.get(position).getDay());

    holder.numberofExercises.setText(programTrackers.get(position).getProgramTrackers().size() + " exercise/s");
    boolean isFinished = false;
    final int sublistSize = programTrackers.get(position).getProgramTrackers().size();
    for (int i = 0; i < sublistSize; i++) {
        if (programTrackers.get(position).getProgramTrackers().get(i).isProgramExerciseFinished()) {
            isFinished = true;

}

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

public class ViewHolder extends RecyclerView.ViewHolder {

    TextView dayTxt, exerciseCompleted, numberofExercises;
    CardView dayCard;

    public ViewHolder(View itemView) {

        super(itemView);

        dayTxt = itemView.findViewById(R.id.dayTxt);
        exerciseCompleted = itemView.findViewById(R.id.exerciseCompleted);
        numberofExercises = itemView.findViewById(R.id.numberofExercises);
        dayCard = itemView.findViewById(R.id.dayCard);
        dayCard.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ((StartProgramActivity) context).setWeekExercisesData(getAdapterPosition());
                ArrayList<ProgramTracker> programTrackerWrappers = ((StartProgramActivity) context).getDayOfWeekExercises();
                if (programTrackerWrappers.size() > 0) {
                    context.startActivity(new Intent(context.getApplicationContext(), DayExerciseActivity.class).putExtra("programExercises", programTrackerWrappers));

                }else {
                    CustomToast customToast = new CustomToast(context);
                    customToast.setTextColor(context.getResources().getColor(R.color.white));
                    customToast.setBackground(context.getResources().getColor(R.color.color_2));

                    customToast.showErrorToast("No exercises for this day.");
                }


            }
        });
    }


}

公共类UserProgramWeekAdapter扩展了RecyclerView.Adapter{
私人语境；
私有ArrayList程序跟踪器；
公共用户ProgramWeekAdapter（上下文上下文、ArrayList程序跟踪器）{
this.context=上下文；
this.programTrackers=programTrackers；
}
@凌驾
public ViewHolder onCreateViewHolder（视图组父级，int-viewType）{
View View=LayoutInflater.from（parent.getContext（））.flate（R.layout.activity\u user\u program\u week\u adapter，parent，false）；
ViewHolder ViewHolder=新的ViewHolder（视图）；
返回视图持有者；
}
@凌驾
BindViewHolder上的公共无效（UserProgramWeekAdapter.ViewHolder，int位置）{
Log.d（“UserProgramWeekAdapter”，“Day:”+programTrackers.get（position.getDay（））；
Log.d（“UserProgramWeekAdapter”，“Size:”+programTrackers.get（position）.getProgramTrackers（）.Size（））；
holder.dayTxt.setText（programTrackers.get（position.getDay（））；
holder.numberofExercises.setText（programTrackers.get（position.getProgramTrackers（）.size（）+“exercise/s”）；
布尔值isFinished=false；
final int sublistSize=programTrackers.get（position.getProgramTrackers（）.size（）；
for（int i=0；i0）{
startActivity（新意图（context.getApplicationContext（），DayExerciseActivity.class）.putExtra（“programExercises”，ProgramTrackerRappers））；
}否则{
CustomToast CustomToast=新的CustomToast（上下文）；
customToast.setTextColor（context.getResources（）.getColor（R.color.white））；
setBackground（context.getResources（）.getColor（R.color.color_2））；
customToast.batherRoToast（“今天没有锻炼。”）；
}
}
});
}
}

我得到的信息：//error//

“DayExerciseActivity中的错误”

首先，您应该使用context而不是context.getApplicationContext，现在讨论这个问题 您正在putExtra中通过programTracker的Arrylist context.startActivity（新意图（context.getApplicationContext（），DayExerciseActivity.class）.putExtra（“programExercises”，ProgramTrackerRappers））；

---

我确信您在DayExerciseActivity中通过programExercise的ArrayList对其进行解析，这就是为什么您会出现此强制转换错误。因为programTracker无法强制转换到programExercise

您在哪一行出现此错误？您好，先生！我添加了一张我从哪里得到错误的照片。请检查与错误无关，但不要在用户界面的

Intent

中使用

context.getApplicationContext（）

。使用简单的

context

您的错误位于

ProgramExercise

和

ProgramTracker

之间。请检查铸造方式，是否为

ProgramTracker

父类或类似类。

public class UserProgramWeekAdapter extends RecyclerView.Adapter<UserProgramWeekAdapter.ViewHolder> {

private Context context;
private ArrayList<ProgramTrackerWrapper> programTrackers;


public UserProgramWeekAdapter(Context context, ArrayList<ProgramTrackerWrapper> programTrackers) {
    this.context = context;
    this.programTrackers = programTrackers;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_user_program_week_adapter, parent, false);
    ViewHolder viewHolder = new ViewHolder(view);
    return viewHolder;

}

@Override
public void onBindViewHolder(UserProgramWeekAdapter.ViewHolder holder, int position) {
    Log.d("UserProgramWeekAdapter", "Day: " + programTrackers.get(position).getDay());
    Log.d("UserProgramWeekAdapter", "Size: " + programTrackers.get(position).getProgramTrackers().size());
    holder.dayTxt.setText(programTrackers.get(position).getDay());

    holder.numberofExercises.setText(programTrackers.get(position).getProgramTrackers().size() + " exercise/s");
    boolean isFinished = false;
    final int sublistSize = programTrackers.get(position).getProgramTrackers().size();
    for (int i = 0; i < sublistSize; i++) {
        if (programTrackers.get(position).getProgramTrackers().get(i).isProgramExerciseFinished()) {
            isFinished = true;

}

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

public class ViewHolder extends RecyclerView.ViewHolder {

    TextView dayTxt, exerciseCompleted, numberofExercises;
    CardView dayCard;

    public ViewHolder(View itemView) {

        super(itemView);

        dayTxt = itemView.findViewById(R.id.dayTxt);
        exerciseCompleted = itemView.findViewById(R.id.exerciseCompleted);
        numberofExercises = itemView.findViewById(R.id.numberofExercises);
        dayCard = itemView.findViewById(R.id.dayCard);
        dayCard.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ((StartProgramActivity) context).setWeekExercisesData(getAdapterPosition());
                ArrayList<ProgramTracker> programTrackerWrappers = ((StartProgramActivity) context).getDayOfWeekExercises();
                if (programTrackerWrappers.size() > 0) {
                    context.startActivity(new Intent(context.getApplicationContext(), DayExerciseActivity.class).putExtra("programExercises", programTrackerWrappers));

                }else {
                    CustomToast customToast = new CustomToast(context);
                    customToast.setTextColor(context.getResources().getColor(R.color.white));
                    customToast.setBackground(context.getResources().getColor(R.color.color_2));

                    customToast.showErrorToast("No exercises for this day.");
                }


            }
        });
    }


}