android - Textview setCompoundDrawables 不会更改或显示

Question

我有一个带有自定义列表项的 ListView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >    
    <ImageView
        android:id="@android:id/icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:contentDescription="@string/app_name"
        android:maxWidth="32dp" />

    <TextView
        android:id="@android:id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center|left"
        android:paddingBottom="4dp"
        android:paddingTop="4dp"
        android:textIsSelectable="true"
        android:textSize="24sp" >

    </TextView>
</LinearLayout>

现在 Eclipse 用This tag and its children can be replaced by one <TextView/> and a compound drawable. 一切正常，但我讨厌警告现在我已经改变了看法。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >
    <TextView
        android:id="@android:id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center|left"
        android:paddingBottom="4dp"
        android:paddingTop="4dp"
        android:textIsSelectable="true"
        android:textSize="24sp"
        android:drawableLeft="@drawable/unstarred" >

    </TextView>
</LinearLayout>

但是图像没有显示，可以告诉我布局有什么问题，这是我的适配器

public class CategoryAdapter extends ArrayAdapter<Category> {

    private Context mContext;
    private int mLayoutResourceId;
    private Category mCategories[] = null;

    public CategoryAdapter(Context context, int layoutResourceId, Category[] data) {
        super(context, layoutResourceId, data);

        mContext = context;
        mCategories = data;
        mLayoutResourceId = layoutResourceId;
    }

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

        View row = convertView;
        Holder holder = null;

        if(null == row) {               
            row = LayoutInflater.from(mContext).inflate(mLayoutResourceId, parent, false);
            holder = new Holder();
            holder.mIcon = (ImageView)row.findViewById(android.R.id.icon);
            holder.mTitle = (TextView)row.findViewById(android.R.id.title);

            row.setTag(holder);
        } else {
            holder = (Holder) row.getTag();
        }

       // obviously only one is used at a time
       // First layout
       final Category category = mCategories[position];
       holder.mTitle.setText(category.getName());
       holder.mIcon
          .setImageResource(category.getStarred() == 1 ? R.drawable.starred : R.drawable.unstarred);            

       // Second layout
       final Category category = mCategories[position];
       final Drawable icon = getResources().getDrawable(category.getStarred() == 1 ? R.drawable.starred : R.drawable.unstarred);
       holder.mTitle.setText(category.getName());
       holder.mTitle.setCompoundDrawables(icon, null, null, null);

        return row;
    }       
}

public static class Holder {
    ImageView mIcon;
    TextView mTitle;        
}

问题是：图像未显示

Answer 1

我改变setCompoundDrawables并setCompoundDrawablesWithIntrinsicBounds最终工作

Answer 2

我知道这是一个老问题，但仍然相关（至少对我而言 ;-)），所以也许其他人正在寻找答案。

尽管user4294815的回答非常接近，但没有一个答案实际上描述了问题所在。

发生这种情况的原因是因为#setBounds()尚未在您的图标上调用，因此它永远不会有任何大小，除了width = 0and height = 0。

此外，如果您查看文档，#setCompoundDrawables()它实际上表明您需要#setBounds()在Drawable设置之前调用Drawable：

/**
 * Sets the Drawables (if any) to appear to the left of, above, to the
 * right of, and below the text. Use {@code null} if you do not want a
 * Drawable there. The Drawables must already have had
 * {@link Drawable#setBounds} called.
 * <p>
 * Calling this method will overwrite any Drawables previously set using
 * {@link #setCompoundDrawablesRelative} or related methods.
 *
 * @attr ref android.R.styleable#TextView_drawableLeft
 * @attr ref android.R.styleable#TextView_drawableTop
 * @attr ref android.R.styleable#TextView_drawableRight
 * @attr ref android.R.styleable#TextView_drawableBottom
 */

现在要解决此问题，您可以调用#setBounds()您的Drawable，或者如果您不Drawable直接使用，则必须使用#setCompoundDrawablesWithIntrinsicBounds()或#setCompoundDrawablesRelativeWithIntrinsicBounds()。后者在今天更合适，因为它不使用leftandright命名，而是使用startand end，因此图标将相对于阅读方向进行设置。

I know that rkmax's own answer answered the question, or at least provided the solution, but sometimes that's not enough - text explaining the issue is more appropriate in my opinion and adds clarification to the next person looking at this question.

Answer 3

添加：

icon.setBounds(0, 0, your icon width, your icon height);

前：

holder.mTitle.setCompoundDrawables(icon, null, null, null);

或者：

holder.mTitle.setCompoundDrawablesWithIntrinsicBounds(category.getStarred() == 1 ? R.drawable.starred : R.drawable.unstarred, null, null, null);

反而。