Question

这是我的数据结构类：

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

这是我写过的适配器：

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;
    }
}

这是列表项的XML：

<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>

我想将ArrayList 步骤的内容添加到ListView中。我无法为步骤预定义XML，因为它们可以具有任何大小。

我希望输出如下所示：

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

那怎么办呢？

Answer 1

假设步数相当小，我通常在这里使用LinearLayout，并添加必要的视图。

为此，您只需在项目视图中添加LinearLayout即可包含这些步骤。

<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>

然后通过适配器向项目视图添加步骤。确保清除视图中的前面步骤（同时确保使用ViewHolder模式）。

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;
    }
}

在这种情况下，createStepView()是读者的练习。

根据您的布局和可能的步骤数量，这可能不是最适合您的解决方案。如果您可能有很多步骤，您可能需要查看某种回收站视图或其他回收容器。

Answer 2

将您的xml文件更改为此

<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>

更改此步骤

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

并在适配器

中

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;
}

如何动态更改Android中ListView的列表项？

2 个答案: