app在運行過程中,爲了後期的維護升級,記錄日誌是一個非常好的方法。
爲了讀取到app運行時的日誌,一般的作法是單獨開一個線程,在app運行的啓動線程,然後app退出時停掉線程。
然而我們更好的方法是開啓一個service,然後在裏面做日誌記錄,代碼如下:
- package com.hai.logcat;
- import java.io.BufferedReader;
- import java.io.DataInputStream;
- import java.io.File;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.InputStreamReader;
- import java.util.List;
- import android.app.ActivityManager;
- import android.app.ActivityManager.RunningAppProcessInfo;
- import android.app.Service;
- import android.content.Intent;
- import android.os.Environment;
- import android.os.IBinder;
- import android.os.Looper;
- import android.util.Log;
- import android.widget.Toast;
- public class MyLogcat extends Service {
- Thread thread;
- boolean readlog = true;
- @Override
- public IBinder onBind(Intent intent) {
- return null;
- }
- @Override
- public void onCreate() {
- super.onCreate();
- Log.d("hhp", "onCreate");
- thread = new Thread(new Runnable() {
- @Override
- public void run() {
- log2();//個人覺得這個方法更實用
- }
- });
- }
- @Override
- public void onStart(Intent intent, int startId) {
- thread.start();
- Log.d("hhp", "onStart");
- super.onStart(intent, startId);
- }
- /**
- * 方法1
- */
- private void log2() {
- Log.d("hhp", "log2 start");
- String[] cmds = { "logcat", "-c" };
- String shellCmd = "logcat -v time -s *:W "; // adb logcat -v time *:W
- Process process = null;
- Runtime runtime = Runtime.getRuntime();
- BufferedReader reader = null;
- try {
- runtime.exec(cmds).waitFor();
- process = runtime.exec(shellCmd);
- reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
- String line = null;
- while ((line = reader.readLine()) != null) {
- if (line.contains(String.valueOf(android.os.Process.myPid()))) {
- // line = new String(line.getBytes("iso-8859-1"), "utf-8");
- writeTofile(line);
- }
- }
- } catch (Exception e) {
- e.printStackTrace();
- }
- Log.d("hhp", "log2 finished");
- }
- /**
- * 方法2
- */
- private void log() {
- Log.d("hhp", "log start");
- String[] cmds = { "logcat", "-c" };
- String shellCmd = "logcat -v time -s *:W ";// //adb logcat -v time *:W
- Process process = null;
- InputStream is = null;
- DataInputStream dis = null;
- String line = "";
- Runtime runtime = Runtime.getRuntime();
- try {
- runtime.exec(cmds);
- process = runtime.exec(shellCmd);
- is = process.getInputStream();
- dis = new DataInputStream(is);
- // String filter = GetPid();
- String filter = android.os.Process.myPid() + "";
- while ((line = dis.readLine()) != null) { //這裏如果輸入流沒斷,會一直循環下去。
- line = new String(line.getBytes("iso-8859-1"), "utf-8");
- if (line.contains(filter)) {
- int pos = line.indexOf(":");
- Log.d("hhp2", line + "");
- writeTofile(line);
- }
- }
- } catch (Exception e) {
- }
- Log.d("hhp", "log finished");
- }
- private void writeTofile(String line) {
- String content = line + "\r\n";
- File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath()
- + "/logcat/myLog.txt");
- if (!file.exists()) {
- try {
- file.createNewFile();
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- FileOutputStream fos;
- try {
- fos = new FileOutputStream(file, true);
- fos.write(content.getBytes());
- fos.flush();
- fos.close();
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- @Override
- public void onDestroy() {
- super.onDestroy();
- stopSelf();
- }
- }
把讀到的信息存入文件中,service停止的時候線程stop,就這麼簡單。
當然要讀入系統日誌還需要添加權限:
<uses-permission Android:name="android.permission.READ_LOGS" />
下面是我記錄的測試日誌,信息記錄的有點多,實際中可以運用正則過濾掉一些信息。
上面的代碼基本可以記錄本app運行中的日誌,但如果中途有未捕獲的異常導致app奔潰,那麼這個未捕獲的異常導致的奔潰上面代碼就記錄不到了。
因爲這個異常導致app奔潰,虛擬機掛掉,那當然記錄日誌的線程也停了。那怎麼捕獲這類我們未捕獲的異常(運行時異常)呢,幸好android這樣
一個接口UncaughtExceptionHandler,當app奔潰前,它會先通知這個接口,這樣我們就可以在app奔潰前做點自己想做的事了。
關於怎麼捕獲奔潰異常,我覺得這位哥們的一片博客寫的不錯http://blog.csdn.net/liuhe688/article/details/6584143#, 我借鑑着改了下:
- package com.hai.logcat;
- import java.io.File;
- import java.io.FileOutputStream;
- import java.io.PrintWriter;
- import java.io.StringWriter;
- import java.io.Writer;
- import java.lang.Thread.UncaughtExceptionHandler;
- import java.lang.reflect.Field;
- import java.text.DateFormat;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import java.util.HashMap;
- import java.util.Map;
- import android.content.Context;
- import android.content.pm.PackageInfo;
- import android.content.pm.PackageManager;
- import android.content.pm.PackageManager.NameNotFoundException;
- import android.os.Build;
- import android.os.Environment;
- import android.os.Looper;
- import android.util.Log;
- import android.widget.Toast;
- public class CrashHandler implements UncaughtExceptionHandler {
- public static final String TAG = "CrashHandler";
- // 系統默認的UncaughtException處理類
- private Thread.UncaughtExceptionHandler mDefaultHandler;
- // CrashHandler實例
- private static CrashHandler INSTANCE = new CrashHandler();
- // 程序的Context對象
- private Context mContext;
- // 用來存儲設備信息和異常信息
- private Map<String, String> infos = new HashMap<String, String>();
- // 用於格式化日期,作爲日誌文件名的一部分
- private DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss ");
- /** 保證只有一個CrashHandler實例 */
- private CrashHandler() {
- }
- /** 獲取CrashHandler實例 ,單例模式 */
- public static CrashHandler getInstance() {
- return INSTANCE;
- }
- /**
- * 初始化
- *
- * @param context
- */
- public void init(Context context) {
- mContext = context;
- // 獲取系統默認的UncaughtException處理器
- mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
- // 設置該CrashHandler爲程序的默認處理器
- Thread.setDefaultUncaughtExceptionHandler(this);
- }
- /**
- * 當UncaughtException發生時會轉入該函數來處理
- */
- @Override
- public void uncaughtException(Thread thread, Throwable ex) {
- if (!handleException(ex) && mDefaultHandler != null) {
- // 如果用戶沒有處理則讓系統默認的異常處理器來處理
- mDefaultHandler.uncaughtException(thread, ex);
- } else {
- try {
- Thread.sleep(3000);
- } catch (InterruptedException e) {
- Log.e(TAG, "error : ", e);
- }
- // 退出程序
- android.os.Process.killProcess(android.os.Process.myPid());
- System.exit(1);
- }
- }
- /**
- * 自定義錯誤處理,收集錯誤信息 發送錯誤報告等操作均在此完成.
- *
- * @param ex
- * @return true:如果處理了該異常信息;否則返回false.
- */
- private boolean handleException(final Throwable ex) {
- if (ex == null) {
- return false;
- }
- // 使用Toast來顯示異常信息
- new Thread() {
- @Override
- public void run() {
- Looper.prepare();
- ex.printStackTrace();
- Toast.makeText(mContext, "很抱歉,程序出現異常,即將退出.", Toast.LENGTH_LONG).show();
- Looper.loop();
- }
- }.start();
- // 收集設備參數信息
- collectDeviceInfo(mContext);
- // 保存日誌文件
- saveCrashInfo2File(ex);
- return true;
- }
- /**
- * 收集設備參數信息
- *
- * @param ctx
- */
- public void collectDeviceInfo(Context ctx) {
- try {
- PackageManager pm = ctx.getPackageManager();
- PackageInfo pi = pm.getPackageInfo(ctx.getPackageName(), PackageManager.GET_ACTIVITIES);
- if (pi != null) {
- String versionName = pi.versionName == null ? "null" : pi.versionName;
- String versionCode = pi.versionCode + "";
- infos.put("versionName", versionName);
- infos.put("versionCode", versionCode);
- }
- } catch (NameNotFoundException e) {
- Log.e(TAG, "an error occured when collect package info", e);
- }
- Field[] fields = Build.class.getDeclaredFields();
- for (Field field : fields) {
- try {
- field.setAccessible(true);
- infos.put(field.getName(), field.get(null).toString());
- Log.d(TAG, field.getName() + " : " + field.get(null));
- } catch (Exception e) {
- Log.e(TAG, "an error occured when collect crash info", e);
- }
- }
- }
- /**
- * 保存錯誤信息到文件中
- *
- * @param ex
- * @return 返回文件名稱,便於將文件傳送到服務器
- */
- private String saveCrashInfo2File(Throwable ex) {
- StringBuffer sb = new StringBuffer();
- for (Map.Entry<String, String> entry : infos.entrySet()) {
- String key = entry.getKey();
- String value = entry.getValue();
- sb.append(key + "=" + value + "\n");
- }
- Writer writer = new StringWriter();
- PrintWriter printWriter = new PrintWriter(writer);
- ex.printStackTrace(printWriter);
- Throwable cause = ex.getCause();
- while (cause != null) {
- cause.printStackTrace(printWriter);
- cause = cause.getCause();
- }
- printWriter.close();
- String result = writer.toString();
- String time = formatter.format(new Date());
- sb.append(time + result);
- try {
- long timestamp = System.currentTimeMillis();
- String fileName = "crash.log";
- if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
- String path =Environment.getExternalStorageDirectory().getAbsolutePath()+ "/logcat/";
- File dir = new File(path);
- if (!dir.exists()) {
- dir.mkdirs();
- }
- FileOutputStream fos = new FileOutputStream(path + fileName, true);
- fos.write((sb.toString()).getBytes());
- fos.close();
- }
- return fileName;
- } catch (Exception e) {
- Log.e(TAG, "an error occured while writing file...", e);
- }
- return null;
- }
- }
上面我們實現了這個接口,然後在奔潰前做了一些友好處理,如存儲奔潰日誌,主動殺死進程,不讓彈出系統的強制關閉對話框。
然後我們在Application中這樣引用即可
- package com.hai;
- import android.app.Application;
- import com.hai.logcat.CrashHandler;
- public class MyApplication extends Application {
- CrashHandler handler = null;
- @Override
- public void onCreate() {
- super.onCreate();
- handler = CrashHandler.getInstance();
- handler.init(getApplicationContext());
- }
- }