Android 4.4之后删除短信进行处理

android 4.4删除短信

android 4.4之后非默认的短信应用已经没有办法删除短信了。像以前那样用如下方法是不会没法删除短信的（即使在xml中配置了短信的读写权限），同时也不会有报错或其他提示。

public void deleteSMS() {
        try {
            ContentResolver CR = getContentResolver();
            // Query SMS
            Uri uriSms = Uri.parse("content://sms/inbox");
            Cursor c = CR.query(uriSms, new String[] { "_id", "thread_id" },
                    null, null, null);
            if (null != c && c.moveToFirst()) {
                do {
                    // Delete SMS
                    long threadId = c.getLong(1);
                    int result = CR.delete(Uri
                            .parse("content://sms/conversations/" + threadId),
                            null, null);
                    Log.d("deleteSMS", "threadId:: " + threadId + "  result::"
                            + result);
                } while (c.moveToNext());
            }
        } catch (Exception e) {
            Log.d("deleteSMS", "Exception:: " + e);
        }
    }

但通过打印可以看到上述代码的result是等于0的，即没有删除掉短信。

这个是因为在：/frameworks/base/services/java/com/android/server/AppOpsService.java中android系统添加了权限检查的函数

检查用户设定权限的函数是：checkOperation() 和 noteOperation()，区别是 checkOperation() 只是检查 Operation 的情况，noteOperation() 还会记录访问时间等信息，代码如下：

@Override
public int checkOperation(int code, int uid, String packageName) {
    verifyIncomingUid(uid);
    verifyIncomingOp(code);
    synchronized (this) {
        Op op = getOpLocked(AppOpsManager.opToSwitch(code), uid, packageName, false);
        if (op == null) {
            return AppOpsManager.MODE_ALLOWED;
        }
        return op.mode;
    }
}

@Override
public int noteOperation(int code, int uid, String packageName) {
    verifyIncomingUid(uid);
    verifyIncomingOp(code);
    synchronized (this) {
        Ops ops = getOpsLocked(uid, packageName, true);
        if (ops == null) {
            if (DEBUG) Log.d(TAG, "noteOperation: no op for code " + code + " uid " + uid
                    + " package " + packageName);
            return AppOpsManager.MODE_IGNORED;
        }
        Op op = getOpLocked(ops, code, true);
        if (op.duration == -1) {
            Slog.w(TAG, "Noting op not finished: uid " + uid + " pkg " + packageName
                    + " code " + code + " time=" + op.time + " duration=" + op.duration);
        }
        op.duration = 0;
        final int switchCode = AppOpsManager.opToSwitch(code);
        final Op switchOp = switchCode != code ? getOpLocked(ops, switchCode, true) : op;
        if (switchOp.mode != AppOpsManager.MODE_ALLOWED) {
            if (DEBUG) Log.d(TAG, "noteOperation: reject #" + op.mode + " for code "
                    + switchCode + " (" + code + ") uid " + uid + " package " + packageName);
            op.rejectTime = System.currentTimeMillis();
            return switchOp.mode;
        }
        if (DEBUG) Log.d(TAG, "noteOperation: allowing code " + code + " uid " + uid
                + " package " + packageName);
        op.time = System.currentTimeMillis();
        op.rejectTime = 0;
        return AppOpsManager.MODE_ALLOWED;
    }
}

然后在ContentProvider可以找到如下代码就是对应用删除短信的权限进行检查

        @Override
        public int delete(String callingPkg, Uri uri, String selection, String[] selectionArgs) {
            validateIncomingUri(uri);
            uri = getUriWithoutUserId(uri);
            if (enforceWritePermission(callingPkg, uri) != AppOpsManager.MODE_ALLOWED) {
                return 0;
            }
            final String original = setCallingPackage(callingPkg);
            try {
                return ContentProvider.this.delete(uri, selection, selectionArgs);
            } finally {
                setCallingPackage(original);
            }
        }

　　　　private int enforceWritePermission(String callingPkg, Uri uri) throws SecurityException {
            enforceWritePermissionInner(uri);
            if (mWriteOp != AppOpsManager.OP_NONE) {
                return mAppOpsManager.noteOp(mWriteOp, Binder.getCallingUid(), callingPkg);
            }
            return AppOpsManager.MODE_ALLOWED;
        }

不过幸运的是在AppOpsService.java中也提供了修改权限的接口：修改某个 App 的某项权限的函数是 setMode()，其中就是修改成员变量 mUidOps。mUidOps 是一个List 保存了某个package对应的所有权限的mode (允许，忽略)，具体代码如下：

@Override
public void setMode(int code, int uid, String packageName, int mode) {
    verifyIncomingUid(uid);
    verifyIncomingOp(code);
    ArrayList<Callback> repCbs = null;
    code = AppOpsManager.opToSwitch(code);
    synchronized (this) {
        Op op = getOpLocked(code, uid, packageName, true);
        if (op != null) {
            if (op.mode != mode) {
                op.mode = mode;
                ArrayList<Callback> cbs = mOpModeWatchers.get(code);
                if (cbs != null) {
                    if (repCbs == null) {
                        repCbs = new ArrayList<Callback>();
                    }
                    repCbs.addAll(cbs);
                }
                cbs = mPackageModeWatchers.get(packageName);
                if (cbs != null) {
                    if (repCbs == null) {
                        repCbs = new ArrayList<Callback>();
                    }
                    repCbs.addAll(cbs);
                }
                if (mode == AppOpsManager.MODE_ALLOWED) {
                    // If going into the default mode, prune this op
                    // if there is nothing else interesting in it.
                    if (op.time == 0 && op.rejectTime == 0) {
                        Ops ops = getOpsLocked(uid, packageName, false);
                        if (ops != null) {
                            ops.remove(op.op);
                            if (ops.size() <= 0) {
                                HashMap<String, Ops> pkgOps = mUidOps.get(uid);
                                if (pkgOps != null) {
                                    pkgOps.remove(ops.packageName);
                                    if (pkgOps.size() <= 0) {
                                        mUidOps.remove(uid);
                                    }
                                }
                            }
                        }
                    }
                }
                scheduleWriteNowLocked();
            }
        }
    }
    if (repCbs != null) {
        for (int i=0; i<repCbs.size(); i++) {
            try {
                repCbs.get(i).mCallback.opChanged(code, packageName);
            } catch (RemoteException e) {
            }
        }
    }
}

AppOpsManager 是一个管理类来和 AppOpsService 通信，两者关联起来的代码如下：

/**
* Common implementation of Context API, which provides the base
* context object for Activity and other application components.
*/
class ContextImpl extends Context {

　　registerService(APP_OPS_SERVICE, new ServiceFetcher() {
　　　　public Object createService(ContextImpl ctx) {
　　　　IBinder b = ServiceManager.getService(APP_OPS_SERVICE);
　　　　IAppOpsService service = IAppOpsService.Stub.asInterface(b);
　　　　return new AppOpsManager(ctx, service);
　　}});

  .....

}

他的函数实现比较简单，重点是把控制转移到 AppOpsService 就可以了。例如 noteOperation() 和 setMode() 在 AppOpsManager 里面调用他们的函数是 noteOp() 和 setMode()，代码如下：

public int noteOp(int op, int uid, String packageName) {
    try {
        int mode = mService.noteOperation(op, uid, packageName);
        if (mode == MODE_ERRORED) {
            throw new SecurityException("Operation not allowed");
        }
        return mode;
    } catch (RemoteException e) {
    }
    return MODE_IGNORED;
}

public void setMode(int code, int uid, String packageName, int mode) {
    try {
        mService.setMode(code, uid, packageName, mode);
    } catch (RemoteException e) {
    }
}

OK，到这里我们应该就能有解决方法了，虽然接口没有公开，但我们在apk中利用反射来调用AppOpsManager，再利用setMode方法来给自己的应用打开权限，代码如下：

public final class SmsWriteOpUtil {
    private static final int OP_WRITE_SMS = 15;

    public static boolean isWriteEnabled(Context context) {
        int uid = getUid(context);
        Object opRes = checkOp(context, OP_WRITE_SMS, uid);

        if (opRes instanceof Integer) {
            return (Integer) opRes == AppOpsManager.MODE_ALLOWED;
        }
        return false;
    }

    public static boolean setWriteEnabled(Context context, boolean enabled) {
        int uid = getUid(context);
        int mode = enabled ? AppOpsManager.MODE_ALLOWED
                : AppOpsManager.MODE_IGNORED;

        return setMode(context, OP_WRITE_SMS, uid, mode);
    }

    private static Object checkOp(Context context, int code, int uid) {
        AppOpsManager appOpsManager = (AppOpsManager) context
                .getSystemService(Context.APP_OPS_SERVICE);
        Class appOpsManagerClass = appOpsManager.getClass();

        try {
            Class[] types = new Class[3];
            types[0] = Integer.TYPE;
            types[1] = Integer.TYPE;
            types[2] = String.class;
            Method checkOpMethod = appOpsManagerClass.getMethod("checkOp",
                    types);

            Object[] args = new Object[3];
            args[0] = Integer.valueOf(code);
            args[1] = Integer.valueOf(uid);
            args[2] = context.getPackageName();
            Object result = checkOpMethod.invoke(appOpsManager, args);

            return result;
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }

    private static boolean setMode(Context context, int code, int uid, int mode) {
        AppOpsManager appOpsManager = (AppOpsManager) context
                .getSystemService(Context.APP_OPS_SERVICE);
        Class appOpsManagerClass = appOpsManager.getClass();

        try {
            Class[] types = new Class[4];
            types[0] = Integer.TYPE;
            types[1] = Integer.TYPE;
            types[2] = String.class;
            types[3] = Integer.TYPE;
            Method setModeMethod = appOpsManagerClass.getMethod("setMode",
                    types);

            Object[] args = new Object[4];
            args[0] = Integer.valueOf(code);
            args[1] = Integer.valueOf(uid);
            args[2] = context.getPackageName();
            args[3] = Integer.valueOf(mode);
            setModeMethod.invoke(appOpsManager, args);

            return true;
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return false;
    }

    private static int getUid(Context context) {
        try {
            int uid = context.getPackageManager().getApplicationInfo(
                    context.getPackageName(), PackageManager.GET_SERVICES).uid;

            return uid;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
            return 0;
        }
    }
}

使用起起来也很方便：

if (!SmsWriteOpUtil.isWriteEnabled(getApplicationContext())) {
            SmsWriteOpUtil.setWriteEnabled(
                    getApplicationContext(), true);
}
deleteSMS();
......

注意还别忘：

<uses-permission android:name="android.permission.READ_SMS" />
<uses-permission android:name="android.permission.WRITE_SMS" />