Get the Area of a Polygon

This program is to measure the area of a polygon. The formula is determinant.

Simple Data Visualization Java Program

I know that other programming languages such Processing or Labview can make data visualization fairly easy. However, because I learned Java recently, I want to try to make a program to show the mouse position.

First, we need a frame and a panel to show the graph.

A panel within a frame. Here is the simple code.

Second, I wrote a function called drawPoint to draw lines. My original thinking is that this function can receive value from external sources. Because if you just want to acquire the mouse position data, we can just get the data and draw in the function. But I didn't.

The function needs an Object Channel argument. This object is to construct an array and an element counter. So, we can add many channels if we want.

Like I said before, the program originally want to get external data. Now, we just try to acquire mouse position, so I need to return the position to the main class.

In the main class, we need to (1) construct a frame, (2) set up channels, and (3) draw the graphs. Pretty easy, right!!

LG gt540 Blue error handler rescue --> success

Last night, I tried to upgrade my LG gt540 to android 2.2 and it worked. However, there is a little problem about the wifi, so I decided to reflash the ROM. Unfortunately, it showed the message of blue error handler. Even I tried another ROM, sometimes it would stuck in the opening screen keeping show "ANDROID". But now I solved the problem. Here is my solution. 


1.  Download the B2CAppSetup from LG website. (We need this program to install the drivers of LG gt540)


2. You have to prepare the KDZ_FW_UPD_EN program to flash the ROM. You can download from here. 


3. Prepare ROM: I have tried many, finally the v20a_00france.kdz was successfully flashed. You can download from here.


4. Then use KDZ_FW_UPD_EN to flash the ROM. You have to let your phone enter the download mode (volume down + Power)


5. After flashing the ROM, the phone may stuck in showing "ANDROID". If so, then use KDZ_FW_UPD_EN flash the V20D_00FB.kdz again, because later we need to use fastboot.

6. After flashing V20D_00FB.kdz, your phone may still stuck in showing "ANDROID". Then shut it down and hold the camera button then plug the USB to let you phone into the fastboot mode. Then you can follow the instruction of upgrading LG gt540 to android 2.2.