[英]Why won't the child views of my custom view render in Marshmallow?
我正在使用Xamarin开发自定义键盘。
我的键盘视图的视图容器本身及其子键视图都有一个重写的OnDraw()。 我还为每个视图适当地使用SetWillNotDraw(false)。 目前,在我的Nexus 10平板电脑上的5.0.1版本中,它运行良好。
在Android 6.0.1中,在Nexus 6和Nexus 6P上,键盘视图会正确绘制自身(只是背景颜色)。 但是,即使我遍历视图层次结构并对每个视图强制无效,也不会绘制子键视图。 这似乎是棉花糖特有的。
我不知道在此版本的Android中是否需要解决一些新问题,或者是否遇到错误。
欢迎任何帮助或建议。
码:
一些额外的细节可以阐明原始帖子:
我们用于键盘渲染的三个主要文件是KeyboardView.cs , KeyboardRowView.cs和KeyView.cs 。
KeyboardView (整个键盘的容器)
渲染没有问题。 KeyboardView扩展了LinearLayout
并运行其OnDraw
方法,并调用Build()
函数来创建所需的内容(只是一个基本背景,它将“保留”各个键):
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,我们这样做是因为我们需要一个自定义键盘,该键盘只能向用户显示某些键/命令。)
KeyboardRowView (每行按键的容器)
这也扩展了LinearLayout
,还具有其OnDraw
方法,称为:
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 (加载和呈现每个单独键的类)
KeyView扩展了View
和View.IOnTouchListener
。 调用了KeyView的构造函数,但从未调用/执行过其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);
在其构造函数/初始化方法中调用函数。 KeyView也具有相同的函数调用,并成功接收需要呈现的每个键值。 我不明白的是为什么它只是...不会...绘制...键盘。 (Argh。)当我与原始海报商谈此事时,他告诉我所有条件都已得到满足,以便呈现键盘键。 我尝试附加断点以查看阻止调用KeyView的OnDraw
的原因,但是陷入了重复的OnMeasure
函数调用中(并且渲染了很多键,因此很快就变老了)。
值得一提的是,我们已经在最新的Nexus 6P智能手机(运行时的Android 6.0棉花糖) 和旧版的Motorola Droid 4(通过CyanogenMod 13安装了棉花糖)上进行了测试。 当我们使用Xamarin Android Player模拟器(运行棉花糖)进行尝试时,它实际上可以工作 ……我的猜测是,模拟器可能毫无问题地渲染了键盘,因为实际的手机本身就是
(a)以某种方式限制访问
(b)可能会保留旧代码,而我们还没有完全删除它们的旧.apks
(c)我没有想到的其他问题
感谢您的时间。 如果有人能想到一个可行的方向,将不胜感激!
通过使用Android文档建议的自上而下方法为每个自定义视图正确实现OnMeasure和OnLayout进行了修复。
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