这可能更多是关于好奇心,而不是解决问题的愿望,因为它似乎是随机发生的,只发生过一次。但是,也许它可能会对java或android的一些模糊方面有所了解。
我们使用Lightstreamer库,本质上它是一个流媒体库,我们为其注册一个简单的侦听器,只要流提供新的值就会调用它。
我在我的应用程序中遇到异常,并检查了logcat中的stacktrace。我无法弄清楚那里发生了什么。这是跟踪的(相关)顶部:
11-25 15:06:50.770 E/AndroidRuntime( 3100): FATAL EXCEPTION: main
11-25 15:06:50.770 E/AndroidRuntime( 3100): java.lang.NullPointerException
11-25 15:06:50.770 E/AndroidRuntime( 3100): at com.lightstreamer.ls_client.UpdateInfoImpl.getNewValue(UpdateInfoImpl.java:142)
11-25 15:06:50.770 E/AndroidRuntime( 3100): at com.ourapp.view.ShrinkingTextViewHelper.onMeasure(ShrinkingTextViewHelper.java:30)
11-25 15:06:50.770 E/AndroidRuntime( 3100): at com.ourapp.view.ButtonEx.onMeasure(ButtonEx.java:67)
11-25 15:06:50.770 E/AndroidRuntime( 3100): at android.view.View.measure(View.java:10828)
这里完整是ShrinkingTextViewHelper.java
:
package com.ourapp.view;
import android.text.TextPaint;
import android.text.TextUtils.TruncateAt;
/**
* Check text size on view and change the text size if it's width not fit to control's width
*
*/
public class ShrinkingTextViewHelper {
public static void onMeasure(ShrinkingTextView view, int widthMeasureSpec, int heightMeasureSpec) {
CharSequence text = view.getText();
view.onMeasureSuper(widthMeasureSpec, heightMeasureSpec);
TextPaint paint = view.getPaint();
float paddings = view.getPaddingLeft() + view.getPaddingRight();
paint.setTextSize(view.getInitialTextSize());
float size = paint.getTextSize();
while (size >= view.getMinTextSize()
&& paddings + paint.measureText(text, 0, text.length()) > view.getMeasuredTextWidth()
&& (view.getLineCount() == 1 || view.getLineCount() > view.getMaxLines())) {
paint.setTextSize(--size);
view.setText(text);
view.onMeasureSuper(widthMeasureSpec, heightMeasureSpec);
}
line 30:if (paddings + paint.measureText(text, 0, text.length()) > view.getMeasuredTextWidth()) {
view.setEllipsize(TruncateAt.END);
}
}
}
这是ButtonEx
类,它也存在于stacktrace中:
package com.ourapp.view;
import android.content.Context;
import android.content.res.TypedArray;
import android.text.method.SingleLineTransformationMethod;
import android.util.AttributeSet;
import android.widget.Button;
import com.ourapp.R;
/**
* Extended button class. It could shrink text on the face.
*
*/
public class ButtonEx extends Button implements ShrinkingTextView {
private static final float DEFAULT_MIN_TEXT_SIZE_DP = 10;
private float minTextSizePx;
private float initialTextSize;
private int maxLines;
/**
* Class constructor
* @param context
* @param attrs
*/
public ButtonEx(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray t = getContext().obtainStyledAttributes(attrs, R.styleable.ButtonEx);
minTextSizePx = t.getDimension(R.styleable.ButtonEx_minTextSize, dipToPixels(DEFAULT_MIN_TEXT_SIZE_DP));
t.recycle();
int att[] = new int[] { android.R.attr.singleLine };
t = getContext().obtainStyledAttributes(attrs, att);
boolean singleLine = t.getBoolean(0, true);
boolean hasSingleLine = t.hasValue(0);
t.recycle();
att = new int[] { android.R.attr.maxLines };
t = getContext().obtainStyledAttributes(attrs, att);
boolean hasMaxLines = t.hasValue(0);
if (singleLine && hasSingleLine) {
maxLines = 1;
} else {
maxLines = t.getInteger(0, 1);
}
if (singleLine && hasSingleLine
|| !hasSingleLine && !hasMaxLines) {
setTransformationMethod(new SingleLineTransformationMethod());
}
setMaxLines(maxLines);
t.recycle();
att = new int[] { android.R.attr.textSize };
t = getContext().obtainStyledAttributes(attrs, att);
initialTextSize = t.getDimension(0, 0);
t.recycle();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
ShrinkingTextViewHelper.onMeasure(this, widthMeasureSpec, heightMeasureSpec);
}
private float dipToPixels(float dip) {
return dip * getContext().getResources().getDisplayMetrics().density;
}
/**
* Get min size of text on title.
*/
public float getMinTextSize() {
return minTextSizePx;
}
/**
* Called to determine the size requirements for this view and all of its children.
*/
public void onMeasureSuper(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
/**
* Get text width
*/
public int getMeasuredTextWidth() {
return getMeasuredWidth();
}
/**
* Get max lines number. It parsed from XML attributes. Default value is 1.
*/
public int getMaxLines() {
return maxLines;
}
@Override
protected void onTextChanged(CharSequence text, int start, int before,
int after) {
super.onTextChanged(text, start, before, after);
requestLayout();
}
/**
* Get initial text size.
*/
public float getInitialTextSize() {
return initialTextSize;
}
}
正如您可能猜到的那样,在帮助器中没有,也从未有过对lightstreamer库的单一引用,它只负责一些自定义视图的测量。这让我觉得这是Dalvik VM中的一个错误。
顺便说一下,应用程序是像往常一样在Eclipse中构建的。是的,按钮上的文字不来自lightstreamer提供的值,我可以保证。
答案 0 :(得分:0)
查看正确的文件/类: - )
例外情况来自ShrinkingTextViewHelper
中的课程com.ourapp.view
,同时发布的课程位于com.ourapp
。
快乐的编码。