It's not good to write short messages and handwritten strokes on mobile phones.

There is something wrong with the handwriting screen. The connecting wire of the touch screen generally has four enameled wires side by side, namely X, X, Y and Y. Generally speaking, X and X control up and down, Y and Y control left and right, and some mobile phones are the other way around. This kind of error may be on the cable, which can be directly checked or replaced. Sometimes the oxidation of cables can also cause this phenomenon. If you disassemble the machine yourself and see that the cable is oxidized, you can clean it with the student elephant skin and put it back.