Android 异常
就 Java 语言来说,所有的异常都继承自 Throwable
- Thorwalbe
-
- Error
-
- Exception
其中,Error 是底层代码产生的,在前端开发时可以不管,但是开发时需要避免引起这类错误,比如图片过大
- Error
-
- VirtualMachineException
而 Exception 是因为代码不规范导致的异常错误,常见的代表性异常:
- IOException
- - FileNoFoundException
- - EOFException
- RuntimeException
- - ClassCastException
- - ArrayIndexOutOfBoundsException
第三方捕获异常库
腾讯的 Bugly
https://bugly.qq.com/
友盟的
异常捕获并存储类
实现抛出一个异常
实现捕获这个异常,并存储到本地文件
添加权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
修改 Application
android:name = “.CrashApplication”
CrashHandler.java
package com.thorn.catchexceptiondemo; import android.annotation.SuppressLint; import android.content.Context; import android.content.pm.PackageInfo; import android.content.pm.PackageManager; import android.os.Build; import android.os.Environment; import android.os.Looper; import android.util.Log; import android.widget.Toast; import java.io.File; import java.io.FileOutputStream; import java.io.PrintWriter; import java.io.StringWriter; import java.io.Writer; import java.lang.reflect.Field; import java.sql.Date; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.HashMap; import java.util.Map; public class CrashHandler implements Thread.UncaughtExceptionHandler { private final String TAG = "CrashHandler"; private final String PATH = Environment.getExternalStorageDirectory().getPath() + "/crash_log/"; // 系统默认的UncaughtException处理类 private Thread.UncaughtExceptionHandler mDefaultHandler; // 程序的Context对象 private Context mContext; // 用来存储设备信息和异常信息 private Map<String, String> infos = new HashMap<String, String>(); // 用于格式化日期,作为日志文件名的一部分 @SuppressLint("SimpleDateFormat") private DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss-SSS"); private CrashHandler() { } /** * 获取CrashHandler实例 ,单例模式 */ @SuppressWarnings("WeakerAccess") protected static CrashHandler getCrashHandlerInstance() { return CrashInstanceHolder.CRASH_INSTANCE; } /** * 初始化 * * @param context */ @SuppressWarnings("WeakerAccess") protected void init(Context context) { mContext = context; // 获取系统默认的UncaughtException处理器 mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler(); // 设置该CrashHandler为程序的默认处理器 Thread.setDefaultUncaughtExceptionHandler(this); } /** * 当UncaughtException发生时会转入该函数来处理 */ @Override public void uncaughtException(Thread thread, Throwable ex) { if (!handleException(ex) && mDefaultHandler != null) { // 如果用户没有处理则让系统默认的异常处理器来处理 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); } } /** * 自定义错误处理,收集错误信息 发送错误报告等操作均在此完成. * * @param ex * @return true:如果处理了该异常信息;否则返回false. */ private boolean handleException(Throwable ex) { if (ex == null) { return false; } // 使用Toast来显示异常信息 new Thread() { @Override public void run() { Looper.prepare(); Toast.makeText(mContext, "很抱歉,程序出现异常即将退出.", Toast.LENGTH_LONG).show(); Looper.loop(); } }.start(); // 收集设备参数信息 collectDeviceInfo(mContext); // 保存日志文件 saveCrashInfoToFile(ex); return true; } /** * 收集设备参数信息 * * @param ctx */ private 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 (PackageManager.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); } } } /** * 保存错误信息到文件中 * * @param ex * @return 返回文件名称, 便于将文件传送到服务器 */ private void saveCrashInfoToFile(Throwable ex) { @SuppressWarnings("StringBufferMayBeStringBuilder") StringBuffer sb = new StringBuffer(); for (Map.Entry<String, String> entry : infos.entrySet()) { String key = entry.getKey(); String value = entry.getValue(); sb.append(key).append("=").append(value).append("\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(); sb.append(result); try { //以当前时间作为文件名 final String FILE_NAME = formatter.format(new Date(System.currentTimeMillis())) + ".txt"; if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { ; File dir = new File(PATH); if (!dir.exists()) { //noinspection ResultOfMethodCallIgnored boolean isMkdirs = dir.mkdirs(); } FileOutputStream fos = new FileOutputStream(PATH + FILE_NAME); fos.write(sb.toString().getBytes("UTF-8")); fos.close(); } } catch (Exception e) { Log.e(TAG, "an error occured while writing file...", e); } } private static final class CrashInstanceHolder { // CrashHandler实例 @SuppressLint("StaticFieldLeak") private static final CrashHandler CRASH_INSTANCE = new CrashHandler(); } }
CrashApplication.java
package com.thorn.catchexceptiondemo; import android.app.Application; public class CrashApplication extends Application { @Override public void onCreate() { super.onCreate(); CrashHandler.getCrashHandlerInstance().init(this); } }
MainActivity.java
package com.thorn.catchexceptiondemo; import android.content.pm.PackageManager; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.v4.app.ActivityCompat; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.View; import android.widget.TextView; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); TextView mTvHello = findViewById(R.id.tv_hello); getPermission();//动态获取权限 mTvHello.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int a = 10 / 0; } }); } private void getPermission() { ActivityCompat.requestPermissions(MainActivity.this, new String[]{android .Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1); } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { super.onRequestPermissionsResult(requestCode, permissions, grantResults); switch (requestCode) { case 1: if (grantResults[0] == PackageManager.PERMISSION_GRANTED) { Log.e("jin","权限获取成功"); break; } default: break; } } }