Android中读取Logcat的缓存

String cmmand=""logcat","-d","-v","time";
String directory="/";
public String execute ( String [] cmmand,String directory)
throws IOException {
String result = "" ;
ProcessBuilder builder = new ProcessBuilder(cmmand);

if ( directory != null )
builder.directory ( new File ( directory ) ) ;
builder.redirectErrorStream (true) ;
Process process = builder.start ( ) ;

//得到命令执行后的结果
InputStream is = process.getInputStream ( ) ;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line = null;
StringBuffer sb = new StringBuffer();
line = bufferedReader.readLine();
while ((line = bufferedReader.readLine()) != null) {
sb.append(line+ "\n");
//strLogcatInfo = strLogcatInfo + line + "\n";
}
return sb.toString();
}
}

使用这种方法读取，得到的信息只有一部分，我现在想将全部的信息都得到。。不知道哪里出了问题
请大家帮帮忙，谢谢啦~