我的自定义视图仅在添加到 onCreate 中时才会绘制 [英] my Custom View gets drawn only when added in onCreate
问题描述
我制作了一个GraphBar"自定义视图,它是一个 RelativeLayout
,底部有一个 TextView
和一个 ImageView
,高度不同,在那之上.代码如下:
I made a "GraphBar" custom view that is a RelativeLayout
with a TextView
on the bottom and an ImageView
, varying in height, above that. Here is the code:
public class GraphBar extends RelativeLayout {
private int mAvailHeight; // space for the bar (component minus label)
private float mBarHeight; // 0.0-1.0 value
public GraphBar(Context context) {
this(context, null);
}
public GraphBar(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public GraphBar(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
LayoutInflater.from(context).inflate(R.layout.graphbar, this, true);
setId(R.id.graphBar); // defined in <merge> but not assigned (?)
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mAvailHeight = getHeight()-findViewById(R.id.label).getHeight();
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
View bar2 = findViewById(R.id.smallBar);
RelativeLayout.LayoutParams llp2 = (RelativeLayout.LayoutParams) bar2.getLayoutParams();
llp2.height = Math.round((float)mAvailHeight * mBarHeight);
}
public void setBarHeight(float value, float max) {
mBarHeight = value / max;
findViewById(R.id.smallBar).requestLayout();
}
public void setLabel(CharSequence c) {
((TextView) findViewById(R.id.label)).setText(c);
}
}
虽然添加这些 GraphBars 并在 onCreate()
中设置它们的高度效果很好,但如果我在创建的条形上创建它们 onClickSomething 或再次调用 setBarHeight()
,唯一的查看更改的方法是加载视图层次结构.有人告诉我此处,这意味着我需要调用requestLayout()
的某个地方.除了修改 mBarHeight
之后还有什么地方?有什么帮助吗?我到处都试过,还有 invalidate()
.
While adding these GraphBars and setting their height in onCreate()
works well, if I create them onClickSomething or call again setBarHeight()
on the created bars, the only way to see changes is Load View Hierarchy. I've been told here that it means I need to call somewhere requestLayout()
. Where else than after modifying mBarHeight
? Any help? I tried everywhere, and with invalidate()
too.
谢谢,安德里亚
(如果您需要,我可以发布用于测试的活动和 graphbar.xml)
(if you need I can post the activity with which i do my tests and the graphbar.xml)
我发现这可能是一个错误.解决方法应该再次调用 requestLayout()
.我仍然不明白我可以在哪里打电话.
I've found it's probably a bug. The workaround should be, again, calling requestLayout()
. Still i don't understand where i can put the call.
推荐答案
我终于找到了再次调用 requestLayout()
的方法.我在构造函数中调用了 setWillNotDraw(false)
以便在 onDraw()
(在 onLayout()
之后)我可以调用额外的 <代码>requestLayout().这会产生一个愚蠢的循环,但从美学上解决了问题.
I've finally found a way to call again requestLayout()
. I called setWillNotDraw(false)
in the constructor so that in onDraw()
(that is after onLayout()
) I can call the extra requestLayout()
. This generates a stupid cycle but solves the problem aesthetically.
如果有人知道更好的解决方案,请告诉我...这里是新代码(修改在评论旁边):
If anyone knows a better solution, let me know... here the new code (modifies are next to comments):
//...
public GraphBar(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
LayoutInflater.from(context).inflate(R.layout.graphbar, this, true);
setWillNotDraw(false); // WORKAROUND: onDraw will be used to make the
// redundant requestLayout() call
setId(R.id.graphBar);
}
//...
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
// i think it's one of the worst workaround one could think of.
// luckily android is smart enough to stop the cycle...
findViewById(R.id.smallBar).requestLayout();
}
public void setBarHeight(float value, float max) {
mBarHeight = value / max;
View bar = findViewById(R.id.smallBar);
bar.requestLayout(); // because when we create this view onDraw is called...
bar.invalidate(); // ...but not when we modify it!!!
//so we need to invalidate too
}
//...
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