Question

撕掉我的头发试图让Android ListView做我想做的事。

我想在单一选择模式下使用ListView，其自定义行布局具有不同的背景颜色，用于选择，按下和检查（即选择以颜色而不是复选标记显示 - 这就是我想要的通常称之为“选择”，但在我按下它之前，选择在android中似乎是我要选择的那一行）

我想过尝试一个背景选择器，里面有三个状态。它适用于state_selected和state_pressed，但不适用于state_checked。所以我创建了一个CheckableRelativeLayout，它扩展了RelativeLayout并实现了Checkable并用于每一行的视图。

此处显示简化版本：

<my.package.CheckableRelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:background="@drawable/bkg_selector">  
  >

     <ImageView android:id="@+id/animage"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentLeft="true"
     />
 </my.package.CheckableRelativeLayout>

bkg_selector看起来像

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:drawable="@drawable/purple" />
    <item android:state_checked="true" android:drawable="@drawable/red" />
    <item android:state_selected="true" android:drawable="@drawable/darkpurple" />
    <item android:drawable="@drawable/black" />
</selector>

颜色在别处定义。

这仍然无效。因此，在自定义ListAdapter中，我跟踪了“已检查”行并尝试了（在getView中）

if（position == checkedPosition）。ret.getBackground（）的setState（CHECKED_STATE_SET）;

它仍然不起作用。我怎样才能让它做我想做的事？

Answer 1

您需要覆盖CheckableRelativeLayout中的onCreateDrawableState并为其设置Clickable =“true”。我的LinearLayout代码：

public class CheckableLinearLayout extends LinearLayout implements Checkable {
private boolean checked = false;

public CheckableLinearLayout(Context context) {
    super(context, null);
}

public CheckableLinearLayout(Context context, AttributeSet attrs) {
    super(context, attrs);       
}

private static final int[] CheckedStateSet = {
    R.attr.state_checked
};

public void setChecked(boolean b) {
    checked = b;
}

public boolean isChecked() {
    return checked;
}

public void toggle() {
    checked = !checked;
}

@Override
protected int[] onCreateDrawableState(int extraSpace) {
    final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
    if (isChecked()) {
        mergeDrawableStates(drawableState, CheckedStateSet);
    }
    return drawableState;
}

@Override
public boolean performClick() {
    toggle();
    return super.performClick();
}

Answer 2

更好的是，不要设置clickable = true并重写CheckableLinearLayout的performClick（），保持Pavel建议覆盖onCreateDrawableState并用以下内容替换CheckableLinearLayout的setChecked（）：

private final List<Checkable> mCheckableViews = new ArrayList<Checkable>();

@Override
protected void onFinishInflate() {
    super.onFinishInflate();
    final int childCount = getChildCount();
    findCheckableChildren(this);
}

private void findCheckableChildren(View v) {
    if (v instanceof Checkable && v instanceof ViewGroup) {
        mCheckableViews.add((Checkable) v);
    }
    if (v instanceof ViewGroup) {
        final ViewGroup vg = (ViewGroup) v;
        final int childCount = vg.getChildCount();
        for (int i = 0; i < childCount; ++i) {
            findCheckableChildren(vg.getChildAt(i));
        }
    }
}

    @Override
    public void setChecked(boolean checked) {
        mChecked = checked;
        for (Checkable c : mCheckableViews) {
            c.setChecked(checked);
        }
        refreshDrawableState();
    }

它可以避免点击和长按回调问题。

Answer 3

恕我直言，使用自定义适配器更容易：

class CustomAdapter extends ArrayAdapter<CustomRowItem> {
    Context context;

    public CustomAdapter(Context context, int resourceId, List<CustomRowItem> items) {
        super(context, resourceId, items);
        this.context = context;
    }

    private class ViewHolder {
        TextView txt;
        View layout;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
        CustomRowItem rowItem = getItem(position);

        LayoutInflater mInflater = (LayoutInflater) context
            .getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.сustom_list, null);
            holder = new ViewHolder();
            holder.txt = (TextView) convertView.findViewById(R.id.сustom_list_txt);
            holder.layout = convertView.findViewById(R.id.сustom_list_layout);
            convertView.setTag(holder);
        } else
            holder = (ViewHolder) convertView.getTag();

        holder.txt.setText(rowItem.getText());
        if(rowItem.isChecked())
            holder.layout.setBackgroundColor(-16720999); //color for checked
        else
            holder.layout.setBackgroundColor(0); //color for unchecked

        return convertView;
    }

}

class CustomRowItem {
    private boolean value;
    private String text;

    public CustomRowItem(String text, boolean value) {
        this.text = text;
        this.value = value;
    }
    public boolean isChecked() {
        return value;
    }
    public void setChecked(boolean checked) {
        value = checked;
    }
    public String getText() {
        return text;
    }
    void setText(String text) {
        this.text = text;
    }
}

сustom_list.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="10dp"
    android:id="@+id/сustom_list_layout" 
    android:orientation="vertical" >
    <TextView
        android:id="@+id/сustom_list_txt"         
        android:textSize="20sp"
        android:layout_width="fill_parent"         
        android:layout_height="fill_parent"/>
</LinearLayout>

如何使用：

public class ExampleAct extends Activity {

    final List<CustomRowItem> list = new ArrayList<CustomRowItem>();
    CustomAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.example);

        ListView listView=(ListView)findViewById(R.id.listView);

        adapter = new CustomAdapter(this, R.layout.сustom_list, list);
        listView.setAdapter(adapter);

        list.add(new CustomRowItem("unchecked item",false));
        list.add(new CustomRowItem("checked item",true));

        adapter.notifyDataSetChanged();

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { //unchecked on click
            @Override
            public void onItemClick(AdapterView<?> parent, View itemClicked, int index, long id) {
                if(list.get(index).isChecked()) {
                    list.get(index).setChecked(false); //uncheck
                    adapter.notifyDataSetChanged();
                } else {
                    // other actions
                }

        });

        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { //checked on long click
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View itemClicked, int index, long id) {
                list.get(index).setChecked(true); //check
                adapter.notifyDataSetChanged();
                return true; // or false for calling context menu
            }
        });

    }

如何让android ListView项选择器使用state_checked

3 个答案: