[英]Why won't the child views of my custom view render in Marshmallow?
我正在使用Xamarin開發自定義鍵盤。
我的鍵盤視圖的視圖容器本身及其子鍵視圖都有一個重寫的OnDraw()。 我還為每個視圖適當地使用SetWillNotDraw(false)。 目前,在我的Nexus 10平板電腦上的5.0.1版本中,它運行良好。
在Android 6.0.1中,在Nexus 6和Nexus 6P上,鍵盤視圖會正確繪制自身(只是背景顏色)。 但是,即使我遍歷視圖層次結構並對每個視圖強制無效,也不會繪制子鍵視圖。 這似乎是棉花糖特有的。
我不知道在此版本的Android中是否需要解決一些新問題,或者是否遇到錯誤。
歡迎任何幫助或建議。
碼:
一些額外的細節可以闡明原始帖子:
我們用於鍵盤渲染的三個主要文件是KeyboardView.cs , KeyboardRowView.cs和KeyView.cs 。
KeyboardView (整個鍵盤的容器)
渲染沒有問題。 KeyboardView擴展了LinearLayout
並運行其OnDraw
方法,並調用Build()
函數來創建所需的內容(只是一個基本背景,它將“保留”各個鍵):
protected override void OnDraw(Canvas canvas)
{
Build();
base.OnDraw(canvas);
// background
Paint bg = new Paint(PaintFlags.AntiAlias);
bg.Color = BG; // light blue
canvas.DrawRect(0, 0, MeasuredWidth, Height, bg);
InvalidateKeys();
}
(...以及下面的Build()
...)
public void Build()
{
// only build once
if (keyLayout != null)
return;
// clear out children
RemoveAllViews();
// define sizes of stuff
if (isPortrait)
{
keyMargin = (int)(MeasuredWidth * .01f);
}
else
{
keyMargin = (int)(MeasuredHeight * .01f);
}
keyWidth = (MeasuredWidth - (keyMargin * 2)) / keyboard.MaxCols;
keyHeight = (MeasuredHeight - (keyMargin * 2)) / keyboard.Rows.Count;
// set general padding around keyboardview
SetPadding(keyMargin, keyMargin, keyMargin, keyMargin);
// build KeyLayout from the keyboard object
keyLayout = new List<List<KeyView>>();
int idx = 0;
foreach (List<Key> row in keyboard.Rows)
{
keyLayout.Add(new List<KeyView>());
// create and add new KeyboardRowView
KeyboardRowView krv = new KeyboardRowView(Context, this, idx);
AddView(krv);
// figure out if we need a margin offset for this row
int extraMargin = 0;
int numCols = CountRowCols(row);
if (numCols < keyboard.MaxCols)
{
// measure full width of the button container and the total row margin
int rowWidth = (int)(numCols * keyWidth);
int rowMargin = MeasuredWidth - (keyMargin * 2) - rowWidth;
// add the offset
extraMargin = rowMargin / 2;
}
// build keys and add them to keyLayout and KeyboardRowView
int idx2 = 0;
foreach (Key key in row)
{
int leftMargin = idx2 == 0 ? extraMargin : 0;
KeyView kv = new KeyView(Context, this, key, leftMargin);
keyLayout[idx].Add(kv);
krv.AddView(kv);
idx2++;
}
idx++;
}
}
(提醒您,我們這樣做是因為我們需要一個自定義鍵盤,該鍵盤只能向用戶顯示某些鍵/命令。)
KeyboardRowView (每行按鍵的容器)
這也擴展了LinearLayout
,還具有其OnDraw
方法,稱為:
protected override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
Paint paint = new Paint();
paint.SetARGB(255, 0, 0, 0);
paint.SetStyle(Paint.Style.Stroke);
paint.StrokeWidth = 3;
canvas.DrawRGB(255, 255, 255);
canvas.DrawRect(0, 0, 100, 100, paint);
}
KeyView (加載和呈現每個單獨鍵的類)
KeyView擴展了View
和View.IOnTouchListener
。 調用了KeyView的構造函數,但從未調用/執行過其OnDraw
方法:
// key views are always dynamically created
public KeyView(Context ctx, KeyboardView parent, Key k, int leftMargin)
: base(ctx)
{
// make sure the key will draw
SetWillNotDraw(false);
keyboard = parent;
key = k;
isDown = false;
// check for an overridden span to adjust width, if needed
int span = string.IsNullOrEmpty(key.Span) ? 1 : Convert.ToInt32(key.Span);
int keyWidth = keyboard.keyWidth + ((span - 1) * keyboard.keyWidth);
width = keyWidth;
height = keyboard.keyHeight;
// set margin
var parameters = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WrapContent,
LinearLayout.LayoutParams.MatchParent
);
parameters.LeftMargin = leftMargin;
LayoutParameters = parameters;
// set touch listener
SetOnTouchListener(this);
// enable haptic feedback for button presses
HapticFeedbackEnabled = true;
}
(...和OnDraw)
protected override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
KeyState primary = key.Primary;
KeyState secondary = key.Secondary;
if (keyboard.swapped)
{
primary = key.Secondary != null ? key.Secondary : key.Primary;
secondary = key.Secondary != null ? key.Primary : null;
}
if (keyboard.shifted)
{
if (primary.Shift != null)
primary = primary.Shift;
if (secondary != null && secondary.Shift != null)
secondary = secondary.Shift;
}
// figure out what color the key is supposed to be
Paint bg = new Paint(PaintFlags.AntiAlias);
bg.Color = GetKeyBgColor(key.Style);
if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Lollipop)
canvas.DrawRoundRect(keyboard.keyMargin, keyboard.keyMargin, width - keyboard.keyMargin, height - keyboard.keyMargin, keyboard.keyMargin, keyboard.keyMargin, bg);
else
canvas.DrawRoundRect(new RectF(keyboard.keyMargin, keyboard.keyMargin, width - keyboard.keyMargin, height - keyboard.keyMargin), keyboard.keyMargin, keyboard.keyMargin, bg);
// draw primary key state
Paint fg = new Paint(PaintFlags.AntiAlias);
fg.TextSize = height * .5f;
fg.Color = GetKeyFgColor(key.Style);
string character = string.IsNullOrEmpty(primary.Character) ? "#" : primary.Character;
int charWidth = Convert.ToInt32(fg.MeasureText(character));
int charX = (width - charWidth) / 2;
canvas.DrawText(character, charX, (height * .7f), fg);
// draw secondary key state
if (secondary != null)
{
fg.TextSize = height * .25f;
fg.Color = GetKeyFgColor(key.Style, true);
character = string.IsNullOrEmpty(secondary.Character) ? "#" : secondary.Character;
charWidth = Convert.ToInt32(fg.MeasureText(character));
charX = width - charWidth - (keyboard.keyMargin * 2);
canvas.DrawText(character, charX, (height * .35f), fg);
}
}
我很困惑。 KeyboardView和KeyboardRowView都具有SetWillNotDraw(false);
在其構造函數/初始化方法中調用函數。 KeyView也具有相同的函數調用,並成功接收需要呈現的每個鍵值。 我不明白的是為什么它只是...不會...繪制...鍵盤。 (Argh。)當我與原始海報商談此事時,他告訴我所有條件都已得到滿足,以便呈現鍵盤鍵。 我嘗試附加斷點以查看阻止調用KeyView的OnDraw
的原因,但是陷入了重復的OnMeasure
函數調用中(並且渲染了很多鍵,因此很快就變老了)。
值得一提的是,我們已經在最新的Nexus 6P智能手機(運行時的Android 6.0棉花糖) 和舊版的Motorola Droid 4(通過CyanogenMod 13安裝了棉花糖)上進行了測試。 當我們使用Xamarin Android Player模擬器(運行棉花糖)進行嘗試時,它實際上可以工作 ……我的猜測是,模擬器可能毫無問題地渲染了鍵盤,因為實際的手機本身就是
(a)以某種方式限制訪問
(b)可能會保留舊代碼,而我們還沒有完全刪除它們的舊.apks
(c)我沒有想到的其他問題
感謝您的時間。 如果有人能想到一個可行的方向,將不勝感激!
通過使用Android文檔建議的自上而下方法為每個自定義視圖正確實現OnMeasure和OnLayout進行了修復。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.