详解Android应用层制作LED指示灯

详解android应用层制作led指示灯

在java应用层修改led指示灯的颜色，这个花了我半天时间， 才实现该功能!

public class ledactivity extends activity implements view.onclicklistener {
private static final string tag = "led";
button mledtest;
int mledstatus = 0;
private final int mledcolorred = 0xffff0000;

final byte[] light_on = { '2', '5', '5' };
final byte[] light_off = { '0' };
private final int red = 0;
private int color = red;
string red_led_dev = " /sys/class/leds/torch/brightness";

public void oncreate(bundle parambundle) {
  super.oncreate(parambundle);
  setcontentview(r.layout.led_test);

  mledtest = ((button)findviewbyid(r.id.ledcolor));
  mledtest.setonclicklistener(this);

 //  setledlightcolor(color);
 //  mledtest.settextcolor(mledcolorred);
 //  mledtest.settext("red"); 
 //  mledstatus = 1;
 }

 public void onclick(view v) {
 log.d("ledactivity", "---onclick---mledstatus=" + mledstatus);
 switch (v.getid()) {
 case r.id.ledcolor:
 if(mledstatus == 0) {
 mledtest.settext("开");
 mledstatus = 1
 }else if(mledstatus == 1) {
   mledtest.settext("关");
   mledstatus = 0;
 }
 break;
 }
 }

 @override
public void finish() {
  setledlightcolor(-1);
  super.finish();
}
private void setledlightcolor(int color) {
  logd("set:" + color);
  boolean red = false;
  switch (color) {
  case red:
    red = true;
    break;
  default:
    break;
  }
  try {
    fileoutputstream fored = new fileoutputstream(red_led_dev);
    log.d(tag, "fored" + fored);
    fred.write(red ? light_on : light_off);
    fred.close();
  } catch (exception e) {
    loge(e);
  }
}
void logd(object d) {
  log.d(tag, "" + d);
}
void loge(object e) {
  log.e(tag, "" + e);
}
}

直接在xml中写一个button,用来实现点击按钮，其实很简单，只是把源码的led指示灯的路径拿出来，用过输出流，将string转化，就能读出灯的状态，直接运行就可以实现该功能.

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