canvas.drawBitmap(mIconBitmap, null, mIconRect, null)这句报空指针

canvas.drawBitmap(mIconBitmap, null, mIconRect, null)这个语句在Eclipse上可以不报错，在Android Studio上会报错诶，求老师指导？？

Edwin_wen

2015-05-18

源自：微信6.0主界面 1-5

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慕粉3885757燕青
2017-06-21

AS在引用自定义布局的时候这样写 xmlns:hyman="http://schemas.android.com/apk/res-auto"

你可以测试你的值，canvas.drawBitmap(mIconBitmap,null, mIconRect,null);
在这语句中其实mIconBitmap是为空的并没有拿到你自定义的任何控件属性；

/**
* 获取自定义属性的值
*
* @param context
* @param attrs
* @param defStyleAttr
*/
public ChangeColorIconWithText(Context context, AttributeSet attrs,
int defStyleAttr)
{
super(context, attrs, defStyleAttr);

TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.ChangeColorIconWithText);
Log.e("测试","a:"+a);
int n = a.getIndexCount();
Log.e("测试","a.getIndexCount():"+a.getIndexCount());
for (int i = 0; i < n; i++)
{

int attr = a.getIndex(i);
Log.e("测试","attr:"+attr);

.......

在进入for 之前所有的值都是 0 ；你自己可以可以测试。

至于说改attrs 里面color；我倒是改了，但是最后我是测到我并没有取到值后我改了我的引用，最后拿到值了就不报错了

06-21 10:26:08.459 24711-24711/com.weixin.weixin_liu E/测试: attr:1
06-21 10:26:08.460 24711-24711/com.weixin.weixin_liu E/测试: attr:2
06-21 10:26:08.460 24711-24711/com.weixin.weixin_liu E/测试: attr:3
06-21 10:26:08.481 24711-24711/com.weixin.weixin_liu E/测试: a:[0, 0, 1, 0, 0, 0, 3, 165, 5, 2130903040, 0, 160, 3, 20, -1, 0, 0, 0, 5, 3074, -1, 0, 0, 0, 0, 0, -1, 0, 1073746944, 0, 0, 0, -1, 0, 1073746944, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 18, 0, 5, 2131427416, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 5, 0, 0, 0, 5, 1281, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 16, 250, -1, 0, 1073746944, 0, 16, 400, -1, 0, 1073746944, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0]
06-21 10:26:08.481 24711-24711/com.weixin.weixin_liu E/测试: a.getIndexCount():3