Android的异常捕获写法

注意只能捕获的异常是throwable类型的，首先我们要建立一个异常捕获的类:

public class CrashHandler implements Thread.UncaughtExceptionHandler {

    public static final String TAG = "CrashHandler";

    private Thread.UncaughtExceptionHandler mDefaultHandler;
    private static CrashHandler INSTANCE = new CrashHandler();
    private Context mContext;
    //文件路径
    private static final String PATH = Environment.getExternalStorageDirectory().getPath() +File.separator+ "crash";
    private static final String FILE_NAME = "crash";
    private static final String FILE_NAME_SUFEIX = ".txt";
    private CrashHandler() {
    }

    public static CrashHandler getInstance() {
        return INSTANCE;
    }

    public void init(Context context) {
        mContext = context;
        mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
        if (mDefaultHandler != null) {
            Thread.setDefaultUncaughtExceptionHandler(this);
        }
    }

    @Override
    public void uncaughtException(Thread thread, Throwable ex) {
        if (mDefaultHandler != null) {
            handleException(ex);
            mDefaultHandler.uncaughtException(thread, ex);
        }
    }

    private boolean handleException(Throwable ex) {
        if (ex == null) {
            return false;
        }

        if (ex instanceof NullPointerException) {
            try {
                //将文件写入sd卡
                writeToSDcard(ex);
                //写入后在这里可以进行上传操作
            } catch (IOException e) {
                e.printStackTrace();
            } catch (PackageManager.NameNotFoundException e) {
                e.printStackTrace();
            }
            return true;
        }
        return false;
    }


    private void writeToSDcard(Throwable ex) throws IOException, PackageManager.NameNotFoundException {
        //如果没有SD卡，直接返回
        if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            return;
        }
        File filedir = new File(PATH);
        if (!filedir.exists()) {
            filedir.mkdirs();
        }
        long currenttime = System.currentTimeMillis();
        String time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(currenttime));

        File exfile = new File(PATH +File.separator+FILE_NAME+time + FILE_NAME_SUFEIX);
        PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(exfile)));
        Log.e("错误日志文件路径",""+exfile.getAbsolutePath());
        pw.println(time);
        PackageManager pm = mContext.getPackageManager();
        PackageInfo pi = pm.getPackageInfo(mContext.getPackageName(), PackageManager.GET_ACTIVITIES);
        //当前版本号
        pw.println("App Version:" + pi.versionName + "_" + pi.versionCode);
        //当前系统
        pw.println("OS version:" + Build.VERSION.RELEASE + "_" + Build.VERSION.SDK_INT);
        //制造商
        pw.println("Vendor:" + Build.MANUFACTURER);
        //手机型号
        pw.println("Model:" + Build.MODEL);
        //CPU架构
        pw.println("CPU ABI:" + Build.CPU_ABI);

        ex.printStackTrace(pw);
        pw.close();
    }

}

我们建立一个activity来测试一下:

public class RainActivity extends Activity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.rain_layout);
        btnStartRain.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                throw new NullPointerException("aa");

            }
        });

    }

然后点击start按钮，程序没有发生crash,我们到sdcard的crash文件夹下，找到这个日志:

打开这个日志:

2019-01-30 08:52:01

App Version:1.0_1

OS version:6.0.1_23

Vendor:OPPO

Model:OPPO R9s Plus

CPU ABI:arm64-v8a

java.lang.NullPointerException: aa

at com.lingan.seeyou.ui.view.raim.RainActivity$1.onClick(RainActivity.java:38)

at android.view.View.performClick(View.java:5231)

at android.view.View$PerformClick.run(View.java:21240)

at android.os.Handler.handleCallback(Handler.java:739)

at android.os.Handler.dispatchMessage(Handler.java:95)

at android.os.Looper.loop(Looper.java:179)

at android.app.ActivityThread.main(ActivityThread.java:5769)

at java.lang.reflect.Method.invoke(Native Method)

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:676)