java - Android 自定义 View 滚动问题

Question

我一直在设计一个需要在自定义 View 上使用滚动条的应用程序。我遇到的问题是，当用户添加新项目时，我的自定义 View 的高度会不断变化。我怀疑这不是一个非常不寻常的问题，但为了使事情复杂化，我实际上并没有向我的自定义 View 添加新对象，我只是在 Canvas 上绘制位图图像。这对我来说很麻烦的原因是当 Android 扩展布局时，它会将大小设置为我告诉它的任何大小 (0dip)，并且当我添加位图时，它只是更改大小以填充 ScrollView ；因此，每当自定义 View 绘制超出当前高度限制的图像时，应用程序不会滚动，而是简单地剪切图片以保持当前高度。

(这是一款纸牌游戏应用，所以我想以一种易于查看和编辑的方式散开您当前的套牌。)

相关代码如下:

public class DeckEdit extends Activity implements FilterQueryProvider  {

static final int PROGRESS_DIALOG = 0;
private Deck deck;
private CardListAdapter lstAdpt;
private ArrayList<CardImage> cards;
private ProgressDialog progressDialog;
private ProgressThread progressThread;
private String[] cardList;
private DeckEditCardView deckGrid;
private ScrollView sc;
protected Cursor cursor;

private EditText filterText = null;
ArrayAdapter<String> adapter = null;

public void onCreate(Bundle savedInstanceBundle){
    super.onCreate(savedInstanceBundle);
    deck = new Deck();
//This is what stores the Card Images that I draw to the canvas with
    cards = new ArrayList<CardImage>();

    setContentView(R.layout.deck_edit_layout);

    sc = (ScrollView) findViewById(R.id.deck_scroller);
    deckGrid = (DeckEditCardView) findViewById(R.id.deck_grid);

    filterText = (EditText) findViewById(R.id.card_search_box);
    filterText.addTextChangedListener(filterTextWatcher);


    pickDeck();
}

然后在我加载甲板后调用它

private void finishSetup(){
    //this is where I set up the deckGrid to have all the cards and then
    deckGrid.setCards(cards);
    //draw them to the screen
    deckGrid.invalidate();
    //This is where I realized that the height value might be causing the problem
    Log.d("finishSetup()", "deckGrid width: "+deckGrid.getWidth());
    Log.d("finishSetup()", "deckGrid height: "+deckGrid.getHeight());
}

DeckEditCardView 类包含这个

public class DeckEditCardView extends View implements OnTouchListener {
private ArrayList<CardImage> cards;

private int X_COLS;
@SuppressWarnings("unused")
private int Y_ROWS;
private final int COL_WIDTH;
private final int ROW_HEIGHT;
private Context context;

private final int X_PADDING = 2;
private final int Y_PADDING = 2;
private final int X_CARD_OVERLAY = 7;
private final int Y_CARD_OVERLAY = 5; 


public DeckEditCardView(Context context) {
    super(context);
    cards = new ArrayList<CardImage>();
    int cardWidth = getResources().getDrawable(R.drawable.back).getIntrinsicWidth();
    int cardHeight = getResources().getDrawable(R.drawable.back).getIntrinsicHeight();
    COL_WIDTH = (X_PADDING+(X_CARD_OVERLAY*3)+cardWidth);
    Log.d("DECV","COLWIDTH 1: "+COL_WIDTH);
    ROW_HEIGHT = (Y_PADDING+(Y_CARD_OVERLAY*3)+cardHeight);
    Log.d("DECV","ROWE_HEIGHT 1: "+ROW_HEIGHT);
}

public DeckEditCardView(Context context, AttributeSet attrs) {
    super(context, attrs);
    cards = new ArrayList<CardImage>();

    int cardWidth = getResources().getDrawable(R.drawable.back).getIntrinsicWidth();
    int cardHeight = getResources().getDrawable(R.drawable.back).getIntrinsicHeight();
    COL_WIDTH = (X_PADDING+(X_CARD_OVERLAY*3)+cardWidth);
    Log.d("DECV","COLWIDTH 2 : "+COL_WIDTH);
    ROW_HEIGHT = (Y_PADDING+(Y_CARD_OVERLAY*3)+cardHeight);
    Log.d("DECV","ROWE_HEIGHT 2: "+ROW_HEIGHT);
}

/*
public DeckEditCardView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    cards = new ArrayList<CardImage>();
    int width = getWidth();
    int height = getHeight();
    int cardWidth = getResources().getDrawable(R.drawable.back).getIntrinsicWidth();
    int cardHeight = getResources().getDrawable(R.drawable.back).getIntrinsicHeight();
    COL_WIDTH = (X_PADDING+(X_CARD_OVERLAY*3)+cardWidth);
    Log.d("DECV","COLWIDTH 3: "+COL_WIDTH);
    ROW_HEIGHT = (Y_PADDING+(Y_CARD_OVERLAY*3)+cardHeight);
    Log.d("DECV","ROWE_HEIGHT 3: "+ROW_HEIGHT);
    X_COLS = (width/COL_WIDTH);
    Y_ROWS = (height/ROW_HEIGHT);

}
*/    
@Override
public void onFinishInflate(){
    super.onFinishInflate();
    //this.
}

public void onSizeChanged(int w, int h, int oldw, int oldh){
    int width = getWidth();
    int height = getHeight();
    X_COLS = (width/COL_WIDTH);
    Y_ROWS = (height/ROW_HEIGHT);

}



public Point getNextCardPoint(Point curP, boolean sameCard){
    Point p=null;
    if (sameCard)
        p = new Point(curP.x+X_CARD_OVERLAY,curP.y+Y_CARD_OVERLAY);
    else { //need to be on the same column
        if (point2Col(curP)+1<X_COLS)
            p = new Point(COL_WIDTH*(point2Col(curP)+1)+X_PADDING,
                ROW_HEIGHT*(point2Row(curP))+Y_PADDING);
        else {//add to new column
            if (point2Row(curP)+1 > Y_ROWS)
                Y_ROWS++;

            p = new Point(X_PADDING,
                    ROW_HEIGHT*(point2Row(curP)+1)+Y_PADDING);
        }
    }
    return p;
}

public void setCards(ArrayList<CardImage> cards){
    this.cards = cards;
}

private int point2Col(Point p){
    return p.x / COL_WIDTH;
}
private int point2Row(Point p){
    return p.y / ROW_HEIGHT;
}


@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    //ScrollView s = new ScrollView(context);
    //s.addView(canvas);
    int length = cards.size();
    CardImage c;
    for (int i = 0; i < length; i++) {
        //Log.d("onDraw", "output a card");
        c = cards.get(i);
        canvas.drawBitmap(c.getBitmap(), c.getX(), c.getY(), null);
    }
}

@Override
public boolean onTouch(View arg0, MotionEvent arg1) {
    // TODO Auto-generated method stub
    return false;
}
}

所以总而言之，我不知道如何让用户滚动并查看屏幕上放不下的卡片(几乎可以保证完整的卡片组会使用滚动条来查看所有卡片。最多使用这段代码，它会放入我需要的所有卡片图像，但是屏幕上出现的图像我不知道该怎么做:/

最后是我的 Layout.xml 文件

<com.xeroxchange.ydd.DeckEditCardView android:layout_weight="2" 
     android:id="@+id/deck_grid" 
     android:layout_width="fill_parent" 
     android:layout_height="0dip"></com.xeroxchange.ydd.DeckEditCardView>
</ScrollView>       
<LinearLayout android:layout_weight="1" 
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

        <!-- Pretty hint text, and maxLines -->
<EditText android:id="@+id/card_search_box" 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:hint="type to filter"
    android:inputType="text"
    android:maxLines="1"/>

    <!-- Set height to 0, and let the weight param expand it -->
    <!-- Note the use of the default ID! This lets us use a 
         ListActivity still! -->
    <ListView android:id="@+id/card_list"
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_weight="2" 
    /> 

</LinearLayout>

</LinearLayout>

Answer 1

您的布局无法正常工作，因为 DeckEditCardView 无法自行测量。您必须覆盖 DeckEditCardView 类中的 View.onMeasure() 方法，并根据 View 的内容设置测量尺寸。在您的布局 xml 文件中，您必须将 wrap_content 指定为 DeckEditCardView 的高度。