Android-无法识别函数的返回名称

Question

我正在使用以下功能，但是在返回值“ fi”时遇到麻烦，出现以下错误：

fi can not be resolved to a variable.

这是我的功能：

public File getBitmapFromwebchartView(WebView view2) {

    if (view2 != null) {
        view2.setDrawingCacheEnabled(true);
        Bitmap b = view2.getDrawingCache();
        if (b != null) {


            try {

                File fi = new File(Environment.getExternalStorageDirectory(), "Screenshot" + ".jpg");
                //fi     = new File(Environment.getExternalStorageDirectory(),"Realitycheck" + ".jpg");

                // write the bytes in file
                FileOutputStream fo;

                fo = new FileOutputStream(fi);

                b.compress(CompressFormat.JPEG, 95, fo);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    return fi;
}

谢谢你的帮助。

Answer 1

如果变量fi在return语句的范围之外，则需要在初始if语句之外定义它。

public File getBitmapFromwebchartView(WebView view2) {

File fi = null;

if (view2 != null) {
    view2.setDrawingCacheEnabled(true);
    Bitmap b = view2.getDrawingCache();
    if (b != null) {


        try {

            fi = new File(Environment.getExternalStorageDirectory(), "Screenshot" + ".jpg");
            //fi     = new File(Environment.getExternalStorageDirectory(),"Realitycheck" + ".jpg");

            // write the bytes in file
            FileOutputStream fo;

            fo = new FileOutputStream(fi);

            b.compress(CompressFormat.JPEG, 95, fo);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
return fi;
}

Answer 2

如果出现以下情况，请声明File对象：

File fi;

范例：

public File getBitmapFromwebchartView(WebView view2) {
    File fi;
    if (view2 != null) {
        view2.setDrawingCacheEnabled(true);
        Bitmap b = view2.getDrawingCache();
        if (b != null) {
         try {
            fi = new File(Environment.getExternalStorageDirectory(), "Screenshot" + ".jpg");
            // write the bytes in file
            FileOutputStream fo;
            fo = new FileOutputStream(fi);
            b.compress(CompressFormat.JPEG, 95, fo);
         } catch (Exception e) {
            e.printStackTrace();
         }
        }
    }
    return fi;
}

Answer 3

那是因为您的fi是在if clause声明的，并且不在范围内。 做这样的事情：

public File getBitmapFromwebchartView(WebView view2) {

    File fi;

    if (view2 != null) {
        view2.setDrawingCacheEnabled(true);
        Bitmap b = view2.getDrawingCache();
        if (b != null) {


            try {

                fi = new File(Environment.getExternalStorageDirectory(), "Screenshot" + ".jpg");
                //fi     = new File(Environment.getExternalStorageDirectory(),"Realitycheck" + ".jpg");

                // write the bytes in file
                FileOutputStream fo;

                fo = new FileOutputStream(fi);

                b.compress(CompressFormat.JPEG, 95, fo);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    return fi;
}