Android致命信号错误11 SIGSEGV关于不同版本的JellyBean

Question

My coworker and I are experiencing very strange behavior with an Android Canvas object.

We're dealing with an initialized canvas object and are selectively getting a Fatal Signal 11 Error between 2 Nexus 7 tablets; one of which runs 4.2.2 and works fine, and the other which runs 4.3 and crashes. We are trying to figure out how to go about troubleshooting the problem which involves determining if the error is on our part, or a glitch somehow in the Android API (unlikely).

The error occurs when we try to call canvas.getWidth() on the object.

Our Java code: ( not that it probably matters but Rect is from our codebase, it's not an android.graphics.Rect )

public Rect getViewportBounds() { 
    Canvas can = _diagram._canvas;
    Rect vb = _viewportBounds;
    if (can == null) return vb;
    Point pos = _position;
    int[] approxWindowVals = { (int) pos.getX(), (int) pos.getY() };
    double sc = _scale;
    vb._set(approxWindowVals[0], approxWindowVals[1], Math.max(can.getWidth(), 0) / sc, Math.max(can.getHeight(), 0) / sc);
    return vb;
}

Our information from LogCat is here

08-09 16:49:14.883: W/View(4083): requestLayout() improperly called by com.nwoods.go.Viewport{41dfcb08 V.ED.... ......I. 0,0-0,0} during layout: running second layout pass
08-09 16:49:14.893: W/View(4083): requestLayout() improperly called by com.nwoods.go.Viewport{41dfcb08 V.ED.... ......I. 0,0-0,0} during second layout pass: posting in next frame
08-09 16:49:14.923: W/View(4083): requestLayout() improperly called by com.nwoods.go.Viewport{41dfcb08 V.ED.... ......I. 0,0-0,0} during layout: running second layout pass
08-09 16:49:14.943: D/abc(4083): onDraw
08-09 16:49:14.943: W/View(4083): requestLayout() improperly called by com.nwoods.go.Viewport{41dfcb08 V.ED.... ......I. 0,0-0,0} during second layout pass: posting in next frame
08-09 16:49:14.973: W/View(4083): requestLayout() improperly called by com.nwoods.go.Viewport{41dfcb08 V.ED.... ......I. 0,0-0,0} during layout: running second layout pass
08-09 16:49:14.983: W/View(4083): requestLayout() improperly called by com.nwoods.go.Viewport{41dfcb08 V.ED.... ......I. 0,0-0,0} during second layout pass: posting in next frame
08-09 16:49:15.003: W/View(4083): requestLayout() improperly called by com.nwoods.go.Viewport{41dfcb08 V.ED.... ......I. 0,0-0,0} during layout: running second layout pass
08-09 16:49:15.033: A/libc(4083): Fatal signal 11 (SIGSEGV) at 0x00000000 (code=1), thread 4083 (egressiontester)

Our hardware configurations are as follows:

+---------+------------+-----------------------+
| Tablet  | Android OS |     Reached Error     |
+---------+------------+-----------------------+
| Nexus 7 | 4.2.2      |                     |
| Nexus 7 | 4.3        | YES                   |
+---------+------------+-----------------------+

If you have any idea as to why this is happening please let me know. We might have to restructure the Canvas, but we're both pretty confused that a class as common as Canvas is behaving differently on two identical tablets.

Thank you very much for your support :)

Answer 1

如果更改的标志为false，则不在第二个布局传递上呈现，这对我来说解决了这个问题。

Answer 2

We fixed this issue by simply assigning our Canvas object to null after using it. Under the hood this probably caused the Android API to reinitialize it with a valid address.

The problem has been solved, but the fact that the address issue got resolved implicitly on 4.2.2 and not on 4.3 is probably a bug and should be researched further.