Question

我在我的应用中使用ZXing条码扫描器库，我遇到以下错误：只有将设备插入充电器时，相机自动对焦才有效。一旦我拔下设备，相机就会停止连续自动对焦，但是一旦再次插入设备，会立即恢复自动对焦（图像每2000毫秒聚焦一次）。测试设备的电池已充满电。

应该注意的是，XZing的示例代码工作正常，但由于我在我的应用程序中使用了它的一部分，我遇到了上述问题。

以下是AutoFocusManager类的代码：

/*Copyright (C) 2012 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.myapp.utils.barcode.camera;

import android.content.Context;
import android.content.SharedPreferences;
import android.hardware.Camera;
import android.os.AsyncTask;
import android.preference.PreferenceManager;
import android.util.Log;

import java.util.ArrayList;
import java.util.Collection;

import com.myapp.utils.barcode.main.PreferencesActivity;
import com.myapp.utils.barcode.common.executor.AsyncTaskExecInterface;
import com.myapp.utils.barcode.common.executor.AsyncTaskExecManager;

final class AutoFocusManager implements Camera.AutoFocusCallback {

  private static final String TAG = AutoFocusManager.class.getSimpleName();

  private static final long AUTO_FOCUS_INTERVAL_MS = 2000L;
  private static final Collection<String> FOCUS_MODES_CALLING_AF;
  static {
    FOCUS_MODES_CALLING_AF = new ArrayList<String>(2);
    FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_AUTO);
    FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_MACRO);
  }

  private boolean active;
  private final boolean useAutoFocus;
  private final Camera camera;
  private AutoFocusTask outstandingTask;
  private final AsyncTaskExecInterface taskExec;

  AutoFocusManager(Context context, Camera camera) {
    this.camera = camera;
    taskExec = new AsyncTaskExecManager().build();
    SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
    String currentFocusMode = camera.getParameters().getFocusMode();
    useAutoFocus =
        sharedPrefs.getBoolean(PreferencesActivity.KEY_AUTO_FOCUS, true) &&
        FOCUS_MODES_CALLING_AF.contains(currentFocusMode);
    Log.i(TAG, "Current focus mode '" + currentFocusMode + "'; use auto focus? " + useAutoFocus);
    start();
  }

  @Override
  public synchronized void onAutoFocus(boolean success, Camera theCamera) {
    if (active) {
      outstandingTask = new AutoFocusTask();
      taskExec.execute(outstandingTask);
    }
  }

  synchronized void start() {
    if (useAutoFocus) {
      active = true;
      try {
        camera.autoFocus(this);
      } catch (RuntimeException re) {
        // Have heard RuntimeException reported in Android 4.0.x+; continue?
        Log.w(TAG, "Unexpected exception while focusing", re);
      }
    }
  }

  synchronized void stop() {
    if (useAutoFocus) {
      try {
        camera.cancelAutoFocus();
      } catch (RuntimeException re) {
        // Have heard RuntimeException reported in Android 4.0.x+; continue?
        Log.w(TAG, "Unexpected exception while cancelling focusing", re);
      }
    }
    if (outstandingTask != null) {
      outstandingTask.cancel(true);
      outstandingTask = null;
    }
    active = false;
  }

  private final class AutoFocusTask extends AsyncTask<Object,Object,Object> {
    @Override
    protected Object doInBackground(Object... voids) {
      try {
        Thread.sleep(AUTO_FOCUS_INTERVAL_MS);
      } catch (InterruptedException e) {
        // continue
      }
      synchronized (AutoFocusManager.this) {
        if (active) {
          start();
        }
      }
      return null;
    }
  }
}

当设备连接到调试器时，LogCat显示以下内容：

03-07 23:37:14.624: I/AutoFocusManager(2296): Current focus mode 'auto'; use auto focus? true

测试设备是HTC感觉，操作系统 - Cyanogenmod 10（Android 4.1.2）。

你有什么建议是什么原因导致这种行为？

谢谢。

Answer 1

类似的情况也发生在我身上zxing 2.1

autoFocusThread X: AF fail

三星Galaxy（GT-P6200）与Android 4.0.4，以及Sonyericcson Xperia Neo / android 4.0.4。

ZXing 2.0没有出现错误。 You can download release 2.0 from here.

尝试一下，我希望也能解决你的自动对焦问题。

从充电器拔下时，Android相机自动对焦会停止

1 个答案: