如何在Android中动态更改ListView的列表项？

Question

Here's my data structure class:

public class FirstAidSteps implements Parcelable {
    //These are the fields
    private final String stepName;
    private final ArrayList<String> steps;
    .
    .
    .
}

Here's the adapter I've written:

public class StepsAdapter extends ArrayAdapter<FirstAidSteps> {
    public StepsAdapter(Context context, ArrayList<FirstAidSteps> users) {
    super(context, 0, users);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        FirstAidSteps steps = getItem(position);

        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item, parent, false);
        }

        TextView stepName = (TextView) convertView.findViewById(R.id.step_heading);
        stepName.setText(steps.getStepName());

        return convertView;
    }
}

Here's the XML for List Item:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

    <TextView
        android:id="@+id/step_heading"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"
        android:textSize="25sp" />

</LinearLayout>

I want to add the contents of ArrayList steps to the ListView. And I can't predefine the XML for steps because they can have any size.

I want the output something like below:

 ___________________
| StepName          |
|   Step            |
|   Step            |
|-------------------|
| StepName          |
|   Step            |
|-------------------|
| StepName          |
|___________________|

So how to do this?

Answer 1

Assuming the number of steps is fairly small, I usually use a LinearLayout here, and add the necessary views.

To do this, you simply need to add a LinearLayout to your item view to contain the steps.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/step_heading"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"
        android:textSize="25sp" />

    <LinearLayout
        android:id="@+id/steps"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

Then you add steps to your item view via the adapter. Make sure you clear the previous steps in the view (also making sure you use the ViewHolder pattern).

public class StepsAdapter extends ArrayAdapter<FirstAidSteps> {

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View v = convertView;
        ViewHolder holder;
        if (v == null) {
            v = LayoutInflater.from(getContext()).inflate(R.layout.list_item, parent, false);
            holder = new ViewHolder();
            holder.stepName = (TextView) v.findViewById(R.id.step_heading);
            holder.steps = (LinearLayout) v.findViewById(R.id.steps);
            v.setTag(holder);
        } else {
            holder = (ViewHolder) v.getTag();
        }

        final FirstAidSteps steps = getItem(position);
        holder.stepName.setText(steps.getStepName());

        holder.steps.removeAllViews();
        for (String step : steps.getSteps()) {
            holder.steps.addView(createStepView(step));
        }

        return v;
    }

    private static class ViewHolder {
        TextView stepName;
        LinearLayout steps;
    }
}

In this case, createStepView() is an exercise for the reader.

Depending on your layout and possible number of steps, this may not be the best solution for you. If you will potentially have a lot of steps you may want to look into some sort of recycler view, or other recycling container.

Answer 2

cahnge your xml file to this

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/step_heading"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"
        android:textSize="25sp" />

    <LinearLayout
        android:id="@+id/steps"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"/>

</LinearLayout>

change steps to this

private final ArrayList<ArrayList<String>> steps;
private final ArrayList<String> stepsName;

and in adapter

public StepsAdapter(Context context, ArrayList<ArrayList<String>> steps, ArrayList<String> stepsName) {
super(context, 0, steps, stepsName);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    if (convertView == null) {
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item, parent, false);
    }

    TextView stepName = (TextView) convertView.findViewById(R.id.step_heading);
    LinearLayout mLinearLayout = (LinearLayout) v.findViewById(R.id.steps);
    stepName.setText(stepsName.get(position));

    mLinearLayout.removeAllViews();

    ArrayList<String> single_step= steps.get(position);

    if(single_step.size() > 0){

        for (int size =0; size <single_step.size(); size++) {

                TextView text = new TextView(this);
                text.setLayoutParams(new LayoutParams(
                            LayoutParams.MATCH_PARENT,
                            LayoutParams.MATCH_PARENT));
                text.setGravity(Gravity.CENTER);
                text.setPadding(5, 2, 5, 2);
                text.setText(single_step.get(size));
                mLinearLayout.addView(text);

        }
    }
    return convertView;
}