Unable to add window -- token null is not for an application

转于：http://blog.csdn.net/wsz1z154/article/details/7724912

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在创建一个Dialog时，发生的错误：

Unable to add window -- token null is not for an application

AlertDialog.Builder builder;
AlertDialog alertDialog;
Context mContext = getApplicationContext();
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.custom_dialog, (ViewGroup)findViewById(R.id.layout_root));

TextView text = (TextView) layout.findViewById(R.id.text);
text.setText("Hello, this is a custom dialog!");
ImageView image = (ImageView) layout.findViewById(R.id.image);
image.setImageResource(R.drawable.icon);
builder = new AlertDialog.Builder(mContext);
builder.setView(layout);
alertDialog = builder.create();
alertDialog.show();

查询SDK帮助文档：

 

Return the context of the single, global Application object of the current process. This generally should only be used if you need a Context whose lifecycle is separate from the current context, that is tied to the lifetime of the process rather than the current component.

 

把这句Context mContext =  getApplicationContext(); 

改成Activity.this即可