proc = Runtime.getRuntime().exec(cmd, null, fwrkDir);
应该
proc = Runtime.getRuntime().exec(cmd, "PATH=$PATH:/android-sdk-linux_x86/platform-tools", fwrkDir);

proc = Runtime.getRuntime().exec(cmd, null, fwrkDir);
应该
proc = Runtime.getRuntime().exec(cmd, "PATH=$PATH:/android-sdk-linux_x86/platform-tools", fwrkDir);