I'm trying to access Activity method from Unity and can't figure out how it works, why it doesn't work. I read various pages like http://forum.unity3d.com/threads/call-a-method-in-an-activity-using-androidjavaobject.219950/ and http://docs.unity3d.com/460/ Documentation / Manual / PluginsForAndroid.html

I am trying to create a camera plugin for Unity. There are some plugins available, but most of them are outdated and do not work. In any case, I could use this knowledge for future use. I originally just used a regular Java class, but to take a picture, I found that the best route was to use intent due to the fact that it is used for quick photos and not for a personalized camera app. To use intent, you need to use an action. The Activity is passed to the Intent, but the Activity must also override the method to get the result from the Intent, as described in the Android documentation. I would link to him, but I am limited to two links.

I am using this to access the activity. However AndroidJavaClass initializes successfully, when I try to get the context I get a null ptr error in the logcat.

C # code

    AndroidJavaClass link = new AndroidJavaClass("com.syncedsoftware.cameralink.CameraLinkActivity");
    AndroidJavaObject activity = link.Call<AndroidJavaObject>("getLinkContext"); // jni null ptr!

    activity.Call("TakePicture");

      

        
        
        
      

    

He never achieves activity. Call ("TakePicture");

Java class - UPDATED WITH STATICS -

public class CameraLinkActivity extends UnityPlayerActivity {

private static Context cameraLinkContext;

public static Context getLinkContext(){
    Log.v("Unityx", "GetLinkContext()");
    return cameraLinkContext;
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.v("Unity", "OnCreate");
    cameraLinkContext = this;
}

public void TakePicture(){
    Log.v("Unity", "TakePicture()");
}
}

      

        
        
        
      

    

Logcat Output - UPDATED WITH NEW STATIC IMPLEMENTATION -

05-29 12:32:50.560    3408-3498/? V/Unityx﹕ GetLinkContext()
05-29 12:32:50.810    3408-3498/? I/Unity﹕ Exception: JNI: Init'd AndroidJavaObject with null ptr!
        at UnityEngine.AndroidJavaObject..ctor (IntPtr jobject) [0x00000] in <filename unknown>:0
        at UnityEngine.AndroidJavaObject.AndroidJavaObjectDeleteLocalRef (IntPtr jobject) [0x00000] in <filename unknown>:0
        at UnityEngine.AndroidJavaObject._CallStatic[AndroidJavaObject] (System.String methodName, System.Object[] args) [0x00000] in <filename unknown>:0
        at UnityEngine.AndroidJavaObject.CallStatic[AndroidJavaObject] (System.String methodName, System.Object[] args) [0x00000] in <filename unknown>:0
        at AndroidCameraLink.Start () [0x00000] in <filename unknown>:0

      

        
        
        
      

    

I noticed that the message in onCreate () is never displayed. This makes me think that the activity is not being created properly and is not being created at all. The activity is never created ",", so onCreate () is never called to initialize the Context field.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.syncedsoftware.cameralink"     android:theme="@android:style/Theme.NoTitleBar" android:versionName="1.0" android:versionCode="1" android:installLocation="preferExternal">
  <supports-screens android:smallScreens="true" android:normalScreens="true" android:largeScreens="true" android:xlargeScreens="true" android:anyDensity="true" />
  <application android:icon="@drawable/app_icon" android:label="@string/app_name" android:debuggable="false">
  <activity android:name="com.unity3d.player.UnityPlayerNativeActivity" android:label="@string/app_name" android:screenOrientation="portrait" android:launchMode="singleTask" android:configChanges="mcc|mnc|locale|touchscreen|keyboard|keyboardHidden|navigation|orientation|screenLayout|uiMode|screenSize|smallestScreenSize|fontScale">
      <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
      </intent-filter>
      <meta-data android:name="unityplayer.UnityActivity" android:value="true" />
      <meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="false" />
    </activity>
<activity android:name="com.syncedsoftware.cameralink.CameraLinkActivity" /> 
      </application>
      <uses-sdk android:minSdkVersion="9" android:targetSdkVersion="18" />
      <uses-feature android:glEsVersion="0x00020000" />
      <uses-permission android:name="android.permission.INTERNET" />
      <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
</manifest>

      

        
        
        
      

    

If anyone can explain why this doesn't work, I would be very grateful. I've been trying to figure this out for almost a week, but to no avail. This is my first time stepping into my home territory with Oneness, please excuse my ignorance.

UPDATE: getLinkContext () is called but the problem persists.

After migrating the implementation to static, I found that I hadn't noticed the logcat message. If you turn it static, getLinkContext () is called successfully, however, this does not fix the original problem of not being able to get an Activity instance.

cameraLinkContext is null because onCreate () is never called. Activity is never created.