**我在使用带有android的TextView时遇到了一些问题：scrollHorizontally =＆＃34; true＆＃34;和计时器。
每次定时器执行Elapsed事件时，TextView的文本都会返回到开始位置，如果经过的时间太短，则文本接缝会发出声音。
但是当计时器未运行时，文本正确滚动。
这是AXML代码：**
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_alignParentTop="true"
android:id="@+id/relFullMinimize">
<ImageButton
android:id="@+id/minimize_image_button_id"
android:src="@drawable/ic_arrow_back_gray"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginTop="15dp"
android:layout_marginLeft="15dp"
android:scaleType="fitXY"
android:clickable="true"
android:layout_alignParentTop="true" />
<ImageButton
android:id="@+id/view_list_image_button_id"
android:src="@drawable/ic_view_list_dark"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginTop="15dp"
android:layout_marginEnd="15dp"
android:scaleType="fitXY"
android:clickable="true"
android:layout_alignParentEnd="true"
android:layout_alignParentTop="true" />
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="center|top"
android:layout_alignParentTop="true"
android:id="@+id/relativeLayout1"
android:layout_toLeftOf="@id/view_list_image_button_id"
android:layout_toRightOf="@id/minimize_image_button_id">
<TextView
android:id="@+id/viewplayerfullsongname"
android:text="Single-line text view that scrolls automatically if the text is too long to fit in the widget"
android:singleLine="true"
android:ellipsize="marquee"
android:marqueeRepeatLimit="marquee_forever"
android:focusable="true"
android:focusableInTouchMode="true"
android:scrollHorizontally="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/viewplayerfullartistname"
android:text="B"
android:layout_below="@id/viewplayerfullsongname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:maxLines="2"
android:textSize="14sp"
android:layout_marginTop="5dp"
android:textColor="#fff1f4f9"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp" />
</RelativeLayout>
</RelativeLayout>
<TextView
android:id="@+id/time"
android:textColor="@android:color/background_dark"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/relFullMinimize"
android:text="Time xxx"
android:layout_centerHorizontal="true"
android:focusable="false" />
<ProgressBar
android:id="@+id/viewplayerProgressBar"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_centerInParent="true"
android:layout_below="@id/time"
android:layout_centerHorizontal="true"
android:focusable="false" />
</RelativeLayout>
这是MainActivity中的代码：
public class MainActivity : Activity
{
int count = 1;
private System.Timers.Timer playerTimer;
TextView time;
ProgressBar viewplayerProgressBar;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
// Get our button from the layout resource,
// and attach an event to it
//Button button = FindViewById<Button>(Resource.Id.myButton);
//button.Click += delegate { button.Text = $"{count++} clicks!"; };
FindViewById<TextView>(Resource.Id.viewplayerfullsongname).Selected = true;
this.playerTimer = new System.Timers.Timer(1000);
this.playerTimer.Elapsed += PlayerTimerHandleElapsed;
this.playerTimer.Start();
this.time = FindViewById<TextView>(Resource.Id.time);
this.viewplayerProgressBar = FindViewById<ProgressBar>(Resource.Id.viewplayerProgressBar);
this.viewplayerProgressBar.Max = 10;
}
private void PlayerTimerHandleElapsed(object sender, System.Timers.ElapsedEventArgs e)
{
this.viewplayerProgressBar.IncrementProgressBy(1);
count++;
if (count > 100)
{
count = 0;
}
RunOnUiThread(() =>
{
this.time.Text = "time: " + count;
}
);
}
我认为问题是关于进度条和TextView的更新名为＆＃34; time＆＃34;使用RunOnUiThred。但如果我不这样做，那些组件的数据就不会刷新。 有人有一些解决方案吗？ 感谢。
答案 0 :(得分：0)
每次计时器执行Elapsed事件时，TextView的文本都会返回到开始位置
以下是您的time布局：
<TextView
android:id="@+id/time"
android:textColor="@android:color/background_dark"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
...
/>
解决方案：
将布局参数android:layout_width从"wrap_content"更改为固定宽度，例如"fill_parent"或"100dp"。
分析：
问题在于，每次更新时间TextView文字时，TextView都会使整个布局无效。
以下是Source code：
/**
* Check whether entirely new text requires a new view layout
* or merely a new text layout.
*/
private void checkForRelayout() {
// If we have a fixed width, we can just swap in a new text layout
// if the text height stays the same or if the view height is fixed.
if ((mLayoutParams.width != LayoutParams.WRAP_CONTENT ||
(mMaxWidthMode == mMinWidthMode && mMaxWidth == mMinWidth)) &&
(mHint == null || mHintLayout != null) &&
(mRight - mLeft - getCompoundPaddingLeft() - getCompoundPaddingRight() > 0)) {
// Static width, so try making a new text layout.
int oldht = mLayout.getHeight();
int want = mLayout.getWidth();
int hintWant = mHintLayout == null ? 0 : mHintLayout.getWidth();
/*
* No need to bring the text into view, since the size is not
* changing (unless we do the requestLayout(), in which case it
* will happen at measure).
*/
makeNewLayout(want, hintWant, UNKNOWN_BORING, UNKNOWN_BORING,
mRight - mLeft - getCompoundPaddingLeft() - getCompoundPaddingRight(),
false);
if (mEllipsize != TextUtils.TruncateAt.MARQUEE) {
// In a fixed-height view, so use our new text layout.
if (mLayoutParams.height != LayoutParams.WRAP_CONTENT &&
mLayoutParams.height != LayoutParams.MATCH_PARENT) {
invalidate();
return;
}
// Dynamic height, but height has stayed the same,
// so use our new text layout.
if (mLayout.getHeight() == oldht &&
(mHintLayout == null || mHintLayout.getHeight() == oldht)) {
invalidate();
return;
}
}
// We lose: the height has changed and we have a dynamic height.
// Request a new view layout using our new text layout.
requestLayout();
invalidate();
} else {
// Dynamic width, so we have no choice but to request a new
// view layout with a new text layout.
nullLayouts();
requestLayout();
invalidate();
}
}