UncaughtExceptionHandler
关于UncaughtExceptionHandler，它是Java Thread类中定义的一个接口；用于处理未捕获的异常导致线程的终止（注意：catch了的是捕获不到的），当我们的应用crash的时候，就会走UncaughtExceptionHandler的uncaughtException方法，在该方法中可以获取到异常的信息，我们通过setDefaultUncaughtExceptionHandler该方法来设置线程的默认异常处理器，将异常信息保存到本地或者是上传到服务器，方便我们快速的定位问题；下面是一个简单CrashHandler的代码：
public class CrashHandler implements Thread.UncaughtExceptionHandler
{
private static final String PATH = Environment.getExternalStorageDirectory().getAbsolutePath();
private static final String FILE_NAME_SUFFIX = ".trace";
private static CrashHandler sInstance = new CrashHandler();
private Thread.UncaughtExceptionHandler mDefaultCrashHandler;
private Context mContext;
private CrashHandler()
{
}
public static CrashHandler getInstance()
{
return sInstance;
}
public void init(@NonNull Context context)
{
mDefaultCrashHandler = Thread.getDefaultUncaughtExceptionHandler();
Thread.setDefaultUncaughtExceptionHandler(this);
mContext = context.getApplicationContext();
}
/**
* 当程序中有未被捕获的异常，系统将会调用这个方法
*
* @param t 出现未捕获异常的线程
* @param e 得到异常信息
*/
@Override
public void uncaughtException(Thread t, Throwable e)
{
try
{
//保存到本地
exportExceptionToSDCard(e);
//下面也可以写上传的服务器的代码
} catch (Exception e1)
{
e1.printStackTrace();
}
e.printStackTrace();
//如果系统提供了默认的异常处理器，则交给系统去结束程序，否则就自己结束自己
if (mDefaultCrashHandler != null)
{
mDefaultCrashHandler.uncaughtException(t, e);
} else
{
Process.killProcess(Process.myPid());
}
}
/**
* 导出异常信息到SD卡
*
* @param e
*/
private void exportExceptionToSDCard(@NonNull Throwable e)
{
//判断SD卡是否存在
if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))
{
return;
}
String time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
File file = new File(PATH + File.separator + time + FILE_NAME_SUFFIX);
try
{
//往文件中写入数据
PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(file)));
pw.println(time);
pw.println(appendPhoneInfo());
e.printStackTrace(pw);
pw.close();
} catch (IOException e1)
{
e1.printStackTrace();
} catch (PackageManager.NameNotFoundException e1)
{
e1.printStackTrace();
}
}
/**
* 获取手机信息
*/
private String appendPhoneInfo() throws PackageManager.NameNotFoundException
{
PackageManager pm = mContext.getPackageManager();
PackageInfo pi = pm.getPackageInfo(mContext.getPackageName(), PackageManager.GET_ACTIVITIES);
StringBuilder sb = new StringBuilder();
//App版本
sb.append("App Version: ");
sb.append(pi.versionName);
sb.append("_");
sb.append(pi.versionCode + "\n");
//Android版本号
sb.append("OS Version: ");
sb.append(Build.VERSION.RELEASE);
sb.append("_");
sb.append(Build.VERSION.SDK_INT + "\n");
//手机制造商
sb.append("Vendor: ");
sb.append(Build.MANUFACTURER + "\n");
//手机型号
sb.append("Model: ");
sb.append(Build.MODEL + "\n");
//CPU架构
sb.append("CPU: ");
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
{
sb.append(Arrays.toString(Build.SUPPORTED_ABIS));
} else
{
sb.append(Build.CPU_ABI);
}
return sb.toString();
}
}
上面代码是当应用发生crash时，判断SD是否存在，然后拿到设备信息和异常信息保存到SD卡根路径.trace文件中；最后将异常交给系统处理，如果没有设置默认的异常处理，就自行终止应用。
Tips：涉及到SD卡，记得在Manifest中添加权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
在Application中初始化CrashHandler
public class App extends Application
{
@Override
public void onCreate()
{
super.onCreate();
CrashHandler.getInstance().init(this);
}
}
下面我们手动抛出异常，然后查看SD卡下的异常信息
public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
private Button mButton;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
//Android M 权限申请
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED)
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
}
private void initView()
{
mButton = (Button) findViewById(R.id.button);
mButton.setOnClickListener(this);
}
@Override
public void onClick(View v)
{
if (v == mButton)
{
throw new RuntimeException("自定义异常");
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
{
if (requestCode == 0)
{
for (int grantResult : grantResults)
{
if (grantResult == PackageManager.PERMISSION_DENIED)
{
Toast.makeText(this, "write_external_storage denied！", Toast.LENGTH_SHORT).show();
}
}
}
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
}
根目录
下面就是保存的设备信息和异常信息
异常信息
