从的字节数组显示图像 [英] display image from byteArray

问题描述

问问题之前，让我告诉你关于我的类层次结构。我有一个主类有的onCreate（）方法。在这种方法我已经做了映射文件类的object.and称为它的 READFILE（）和 readIndex（）的方法。在 readIndex（）方法，我调用另一个类名为 MapTile 在这里，我读了我的二进制文件中的图像砖和有我要显示我的形象。

before asking question let me tell you about my class hierarchy. i have a Main class with has onCreate() method. in that method i have made the MapFile class' object.and called its readFile() and readIndex() methods. in readIndex() method i call another class named MapTile where i read the images tiles from my binary file and there i have to display my image.

现在的问题是，我怎么能显示图像而没有把我的code到的onCreate（包savedInstanceStare） method.i在尝试这种方式，但在第一行它给我空指针异常。

now question is how can i display image without putting my code into onCreate(Bundle savedInstanceStare) method.i am trying this way but on first line it gives me null pointer exception.

ImageView image = (ImageView) findViewById(android.R.id.icon);           
Bitmap bMap = BitmapFactory.decodeByteArray(imageTile, 0, imageTile.length);
image.setImageBitmap(bMap);

在此先感谢。

推荐答案

我觉得你的问题不是的字节数组，但 findViewById 。正如你说，NPE是在第一行。有规则解决这个方法，你有两个选择来调用它：

I think your issue is not the byteArray but the findViewById. As you say that the NPE is on the first line. There are rules around this method you have two options to call it :

无论你用它来查询查看你已经在你的的setContentView
称为布局 或者你包含在布局视图你手动布局气筒充气使用它

Either you use it to query a View you already have in the layout you called in setContentView
Or you use it on a View contained in a layout you inflated manually with a layout inflater

如果您尝试使用它在你的活动中调用的setContentView ，你有没有夸大自己从不是一个任何其他布局视图，它会返回null。

If you try to use it in your activity to call a View from any other layout than the one in setContentView that you have not inflated yourself, it will return null.

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