使用相机闪光灯作为手电筒的应用程序使用 Eclipse 不工作
Posted
技术标签:
【中文标题】使用相机闪光灯作为手电筒的应用程序使用 Eclipse 不工作【英文标题】：App using camera flash as a torch using Eclipse not working 【发布时间】：2013-06-19 20:54:36 【问题描述】：我一直在开发一款将手机/平板电脑的相机闪光灯用作手电筒的应用。一切似乎都运行良好，但是当我在运行 android 4.1.2 的 Droid Bionic 上对其进行测试时，该应用程序无法打开闪光灯，即使它说可以。这是我使用的java代码：
package com.example.flash;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity
private boolean isFlashOn = false;
private Camera camera;
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.buttonFlashlight);
Context context = this;
PackageManager pm = context.getPackageManager();
if(!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA))
Log.e("err", "Device has no camera!");
Toast.makeText(getApplicationContext(),
"Your device doesn't have camera!",Toast.LENGTH_SHORT).show();
return;
camera = Camera.open();
final Parameters p = camera.getParameters();
button.setOnClickListener(new OnClickListener()
public void onClick(View arg0)
if (isFlashOn)
Log.i("info", "torch is turned off!");
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
isFlashOn = false;
button.setText("Tap to turn flashlight on.");
else
Log.i("info", "torch is turned on!");
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
isFlashOn = true;
button.setText("Tap to turn flashlight off.");
);
@Override
public boolean onCreateOptionsMenu(Menu menu)
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
@Override
protected void onStop()
super.onStop();
if (camera != null)
camera.release();
这段代码是正确的还是我遗漏了什么？
Logcat：
07-03 18:48:29.064: E/Trace(773): error opening trace file: No such file or directory (2)
07-03 18:48:30.535: D/Camera(773): app passed NULL surface
07-03 18:48:31.023: D/libEGL(773): loaded /system/lib/egl/libEGL_emulation.so
07-03 18:48:31.073: D/(773): HostConnection::get() New Host Connection established 0x2a13c3c0, tid 773
07-03 18:48:31.123: D/libEGL(773): loaded /system/lib/egl/libGLESv1_CM_emulation.so
07-03 18:48:31.173: D/libEGL(773): loaded /system/lib/egl/libGLESv2_emulation.so
07-03 18:48:31.406: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:48:31.433: D/OpenGLRenderer(773): Enabling debug mode 0
07-03 18:48:31.723: I/Choreographer(773): Skipped 58 frames! The application may be doing too much work on its main thread.
07-03 18:49:05.923: D/dalvikvm(773): GC_CONCURRENT freed 202K, 12% free 2623K/2956K, paused 74ms+25ms, total 234ms
07-03 18:49:06.216: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:49:09.584: D/Camera(773): app passed NULL surface
07-03 18:49:09.853: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:49:11.813: I/info(773): torch is turned on!
07-03 18:49:13.467: I/info(773): torch is turned off!
07-03 18:49:16.263: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:49:16.713: D/AndroidRuntime(773): Shutting down VM
07-03 18:49:16.713: W/dalvikvm(773): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
07-03 18:49:16.936: E/AndroidRuntime(773): FATAL EXCEPTION: main
07-03 18:49:16.936: E/AndroidRuntime(773): java.lang.RuntimeException: Method called after release()
07-03 18:49:16.936: E/AndroidRuntime(773): at android.hardware.Camera._stopPreview(Native Method)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.hardware.Camera.stopPreview(Camera.java:543)
07-03 18:49:16.936: E/AndroidRuntime(773): at com.example.flash.MainActivity.surfaceDestroyed(MainActivity.java:140)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.SurfaceView.updateWindow(SurfaceView.java:553)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:231)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.View.dispatchWindowVisibilityChanged(View.java:7544)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1211)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer.doFrame(Choreographer.java:532)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.os.Handler.handleCallback(Handler.java:725)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.os.Handler.dispatchMessage(Handler.java:92)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.os.Looper.loop(Looper.java:137)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-03 18:49:16.936: E/AndroidRuntime(773): at java.lang.reflect.Method.invokeNative(Native Method)
07-03 18:49:16.936: E/AndroidRuntime(773): at java.lang.reflect.Method.invoke(Method.java:511)
07-03 18:49:16.936: E/AndroidRuntime(773): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-03 18:49:16.936: E/AndroidRuntime(773): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-03 18:49:16.936: E/AndroidRuntime(773): at dalvik.system.NativeStart.main(Native Method)
07-03 18:49:24.854: E/Trace(811): error opening trace file: No such file or directory (2)
07-03 18:49:25.413: D/libEGL(811): loaded /system/lib/egl/libEGL_emulation.so
07-03 18:49:25.567: D/(811): HostConnection::get() New Host Connection established 0x2a15f570, tid 811
07-03 18:49:25.643: D/libEGL(811): loaded /system/lib/egl/libGLESv1_CM_emulation.so
07-03 18:49:25.663: D/libEGL(811): loaded /system/lib/egl/libGLESv2_emulation.so
07-03 18:49:25.934: W/EGL_emulation(811): eglSurfaceAttrib not implemented
07-03 18:49:25.963: D/OpenGLRenderer(811): Enabling debug mode 0
07-03 18:53:12.298: D/Camera(811): app passed NULL surface
07-03 18:53:12.723: D/dalvikvm(811): GC_CONCURRENT freed 172K, 11% free 2600K/2904K, paused 9ms+165ms, total 421ms
07-03 18:53:12.934: E/EGL_emulation(811): rcCreateWindowSurface returned 0
07-03 18:53:12.934: E/EGL_emulation(811): tid 811: eglCreateWindowSurface(631): error 0x3003 (EGL_BAD_ALLOC)
07-03 18:53:12.943: D/AndroidRuntime(811): Shutting down VM
07-03 18:53:12.943: W/dalvikvm(811): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
07-03 18:53:13.033: E/AndroidRuntime(811): FATAL EXCEPTION: main
07-03 18:53:13.033: E/AndroidRuntime(811): java.lang.RuntimeException: createWindowSurface failed EGL_BAD_ALLOC
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.HardwareRenderer$GlRenderer.createSurface(HardwareRenderer.java:1064)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.HardwareRenderer$GlRenderer.createEglSurface(HardwareRenderer.java:961)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.HardwareRenderer$GlRenderer.initialize(HardwareRenderer.java:787)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1502)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer.doFrame(Choreographer.java:532)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.os.Handler.handleCallback(Handler.java:725)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.os.Handler.dispatchMessage(Handler.java:92)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.os.Looper.loop(Looper.java:137)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-03 18:53:13.033: E/AndroidRuntime(811): at java.lang.reflect.Method.invokeNative(Native Method)
07-03 18:53:13.033: E/AndroidRuntime(811): at java.lang.reflect.Method.invoke(Method.java:511)
07-03 18:53:13.033: E/AndroidRuntime(811): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-03 18:53:13.033: E/AndroidRuntime(811): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-03 18:53:13.033: E/AndroidRuntime(811): at dalvik.system.NativeStart.main(Native Method)
【问题讨论】：
您的 LogCat 说什么？你在其他设备上测试过吗？ 它不显示任何错误。当我单击模拟器上的按钮时，它还会显示“手电筒已打开”或“手电筒已关闭”。我无法在其他设备上测试它，因为我没有其他运行 android 并有相机闪光灯的设备。 如果在声明“参数 p”时删除关键字 final 会发生什么？ 当我删除关键字 final 时，当我稍后使用“p”时会收到多条错误消息。 【参考方案1】：更新
我认为关键是您运行的是 Android 4.1.2。从Android 4.0开始，如果你想使用Camera Device，即使你只想使用闪光灯，也不得不使用SurfaceView。
在上一个答案（如下）中，我给了你一个指向Torch app which uses SurfaceView 的链接。尝试一下或根据您的代码调整它。
以前的答案：
正如在许多其他情况 (like this one) 中所述，您可能会遇到在 Android 世界中非常常见的特定于设备的问题。
虽然getSupportedFlashModes() 可能会在几乎所有设备上返回FLASH_MODE_TORCH，但其中许多实际上并不支持它。
不管怎样，你可以试试这些：
在camera = Camera.open(); 之后使用camera.startPreview();
最初尝试设置FLASH_MODE_OFF（在camera.startPreview();之前）。
检查this Torch app 是否在您的设备中工作。如果确实如此，您可以将其与您的源代码进行比较。
从 Play 商店下载 Torch 应用以测试是否是设备问题。
在Droid Bionic support forum 中发布问题。
更新：我想说final 关键字是您的代码中的一个问题。尝试将其更改为：
//camera = Camera.open();
//final Parameters p = camera.getParameters();
button.setOnClickListener(new OnClickListener()
public void onClick(View arg0)
if (isFlashOn)
Log.i("info", "torch is turned off!");
cam.stopPreview();
cam.release();
isFlashOn = false;
button.setText("Tap to turn flashlight on.");
else
Log.i("info", "torch is turned on!");
camera = Camera.open();
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.startPreview();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
isFlashOn = true;
button.setText("Tap to turn flashlight off.");
);
【讨论】：
我按照您的建议进行了更改，但仍然无效。我还在 Play 商店中安装了该应用程序和另一个应用程序。您推荐的应用程序在我的手机上根本无法运行，但另一个运行良好...... This guy 是 TeslaLED 的开发者。在您的设备中尝试该应用程序。如果有效，请尝试this code（他告诉那里他正在使用它）。 我对此很陌生，所以请耐心等待...我用相应的代码替换了新代码，但它无法识别 cam 变量。它应该自然地认识到这一点还是我需要在某个地方声明它？ 您必须声明它，就像您在原始代码中使用“私人相机相机”所做的那样；声明。 改代码声明私有Camera cam还是不行；【参考方案2】：在清单中使用权限"android.permission.FLASHLIGHT"
<uses-permission android:name="android.permission.FLASHLIGHT" />
<uses-permission android:name="android.permission.CAMERA" />
【讨论】：
我已经将它们与以上是关于使用相机闪光灯作为手电筒的应用程序使用 Eclipse 不工作的主要内容，如果未能解决你的问题，请参考以下文章
如何在不破坏相机应用程序的情况下在Android手机上打开手电筒[重复]