我正在尝试使用card_layout创建一个ListView,它接受ImageView和3个TextViews:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal">
<ImageView
android:id="@+id/book_cover"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2"/>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="8"
android:orientation="vertical">
<TextView
android:id="@+id/book_author"
style="@style/subheading_style"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/book_title"
style="@style/heading_style"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/book_completion_status"
style="@style/third_heading_style"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
使用CardItem对象填充卡片
public class CardItem
{
private String bookAuthor;
private String bookTitle;
private String bookCompletionStatus;
private int bookCoverResID;
/*
* Constructors
*/
public CardItem(String bookTitle)
{
this.bookTitle = bookTitle;
bookCoverResID = 0;
}
public CardItem(String bookTitle, String bookAuthor, String bookCompletionStatus)
{
this.bookAuthor = bookAuthor;
this.bookTitle = bookTitle;
this.bookCompletionStatus = bookCompletionStatus;
bookCoverResID = 0;
}
public CardItem(String bookTitle, String bookAuthor, String bookCompletionStatus, int bookCoverResID)
{
this.bookAuthor = bookAuthor;
this.bookTitle = bookTitle;
this.bookCompletionStatus = bookCompletionStatus;
this.bookCoverResID = bookCoverResID;
}
/*
* Getters and Setters
*/
public String getBookAuthor() {
return bookAuthor;
}
public void setBookAuthor(String bookAuthor) {
this.bookAuthor = bookAuthor;
}
public String getBookTitle() {
return bookTitle;
}
public void setBookTitle(String bookTitle) {
this.bookTitle = bookTitle;
}
public int getBookCoverResID() {
return bookCoverResID;
}
public void setBookCoverResID(int bookCoverResID) {
this.bookCoverResID = bookCoverResID;
}
public String getBookCompletionStatus() {
return bookCompletionStatus;
}
public void setBookCompletionStatus(String bookCompletionStatus) {
this.bookCompletionStatus = bookCompletionStatus;
}
/*
* misc. methods
*/
public boolean hasBookCover()
{
return (bookCoverResID!=0);
}
}
并使用CardItemAdapter填充listview
public class CardItemAdapter extends ArrayAdapter<CardItem>
{
public CardItemAdapter(@NonNull Context context, int resource, @NonNull List<CardItem> objects) {
super(context, resource, objects);
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent)
{
View tempView = convertView;
if(tempView == null)
tempView = LayoutInflater.from(getContext()).inflate( R.layout.card_layout, parent, false);
TextView bookAuthor = tempView.findViewById(R.id.book_author);
TextView bookTitle = tempView.findViewById(R.id.book_title);
TextView bookCompletionStatus = tempView.findViewById(R.id.book_completion_status);
ImageView bookCover = tempView.findViewById(R.id.book_cover);
bookTitle.setText(getItem(position).getBookTitle());
if(bookAuthor != null)
bookAuthor.setText(getItem(position).getBookAuthor());
if(bookCompletionStatus != null)
bookCompletionStatus.setText(getItem(position).getBookCompletionStatus());
if(getItem(position).hasBookCover())
bookCover.setImageResource(getItem(position).getBookCoverResID());
else
bookCover.setVisibility(View.GONE);
return tempView;
}
}
这是onCreate中MainActivity的代码
ListView listView;
ArrayList<CardItem> cardItems = new ArrayList<>();
cardItems.add(new CardItem("Origin", "Dan Brown", "Completed"));
cardItems.add(new CardItem("A Column of Fire"));
cardItems.add(new CardItem("People vs Alex Cross", "James Patterson",
"Completed", R.raw.people_vs_alex_cross));
listView = findViewById(R.id.list_view);
listView.setAdapter(new CardItemAdapter(this, R.layout.activity_main, cardItems));
Android应用程序总是在启动时崩溃,在setImageResourceID中的适配器的getView()方法中给出了OutOfMemoryError。该应用程序工作正常,没有if / else语句。我使用的图像是存储在res \ raw文件夹中的.jpg文件。
res/raw/
中的图像行为没有很好的记录。我建议将图像放在可绘制的资源目录中。如果要在所有屏幕密度上使用相同的图像,请使用res/drawable-anydpi/
。
除此之外,请确保您的图像具有合理的分辨率。图像使用的内存量是分辨率的函数,而不是磁盘大小。例如,1536 x 2344像素图像将消耗4 * 1536 * 2344字节= 14,401,536字节= ~14MB。您不太可能拥有大的连续空闲内存块。
放
android:largeHeap=true
在清单应用标签中