安卓:检查闪光手电筒模式是否激活不起作用

Question

[WORIKING CODE/22.01.2013]

以下代码不起作用，我不知道为什么。我设置了权限和按钮，以便它应该可以工作...

我在清单中设置权限如下：

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="spicysoftware.spicytaschenlampe"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="17" />
    <uses-permission android:name="android.permission.CAMERA" />
<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="spicysoftware.spicytaschenlampe.FlashLight"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

这就是代码：（它可以打开手电筒，但不能关闭...

Parameters p;
Camera cam;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    check_for_flash();
    cam = Camera.open();     
    cam.startPreview();
    p = cam.getParameters();
    Button cmd_flash_light = (Button) findViewById(R.id.cmd_flash_light);
    cmd_flash_light.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {

            if(p.getFlashMode().equals(android.hardware.Camera.Parameters.FLASH_MODE_TORCH)){
                Log.v("FLASH_LIGHT_ON", "TRUE");
                //p.setFlashMode(Parameters.FLASH_MODE_OFF);
            } else {
                Log.v("FLASH_LIGHT_ON", "FALSE");
                p.setFlashMode(Parameters.FLASH_MODE_TORCH);
            }
            cam.setParameters(p);
        }
    });
}

这是日志猫错误：

01-22 08:11:00.290: D/AndroidRuntime(12239): Shutting down VM
01-22 08:11:00.290: W/dalvikvm(12239): threadid=1: thread exiting with uncaught exception (group=0x40dfc2a0)
01-22 08:11:00.290: E/AndroidRuntime(12239): FATAL EXCEPTION: main
01-22 08:11:00.290: E/AndroidRuntime(12239): java.lang.RuntimeException: Fail to connect to camera service
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.hardware.Camera.native_setup(Native Method)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.hardware.Camera.<init>(Camera.java:353)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.hardware.Camera.open(Camera.java:330)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at spicysoftware.spicytaschenlampe.FlashLight$1.onClick(FlashLight.java:28)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.view.View.performClick(View.java:4223)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.view.View$PerformClick.run(View.java:17275)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.os.Handler.handleCallback(Handler.java:615)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.os.Handler.dispatchMessage(Handler.java:92)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.os.Looper.loop(Looper.java:137)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at android.app.ActivityThread.main(ActivityThread.java:4898)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at java.lang.reflect.Method.invokeNative(Native Method)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at java.lang.reflect.Method.invoke(Method.java:511)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
01-22 08:11:00.290: E/AndroidRuntime(12239):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

在清单中进行以下更改：

<uses-permission android:name="android.permission.CAMERA"/>
<uses-feature android:name="android.hardware.camera"/>
<uses-feature android:name="android.hardware.camera.autofocus" android:required="true"/>

执行Camera.open()并设置参数后，执行mCamera.startPreview()。这应该可以解决问题。

在onClick()之前声明Camera cam