» androidStudio の記事

1)clean project rebuild

2)restart android studio

3)File->Invalidate cache and restart

4)open android terminal
first time use Gradle have to change the permission
chmod +x gradlew
./gradlew compileDebugSource –stacktrace -info
then see the error for details

Please add this to AndroidManifest.xml:
<uses-library
    android:name="org.apache.http.legacy"
    android:required="false" />

-logcat setting change it to floating mode and disable the floating mode, and double click the logcat bar to resize the logcat, it i will appear again

-if still cannot fix restart android studio and retry

-create project with no activity

-libs copy unity classes file
C:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer\Variations\mono\Release\Classes\classes.jar

-Gradle window =>refresh Gradle project

Create Class MainActivity.class

package hk.connie.testunitypackage;

import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.widget.Toast;

import com.unity3d.player.UnityPlayerActivity;

public class MainActivity extends UnityPlayerActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    public String ShowDialog(final String _title, final String _content){
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                builder.setTitle(_title).setMessage(_content).setPositiveButton("Down", null);
                builder.show();
            }
        });
        return "Java return";
    }

    public void ShowToast(final String mStr2Show){
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(getApplicationContext(),mStr2Show, Toast.LENGTH_LONG).show();
            }
        });
    }

}

AndroidManifest.xml

<application>
.....
<activity android:name="hk.connie.testunitypackage.MainActivity">
    <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" />
</activity>
..... 
</application> 

build.gradle

Change
apply plugin: ‘com.android.application’
to
apply plugin: ‘com.android.library’

and del
applicationid

Go to Gradle Windows > select the package >tasks > Build > assemble

Then it will generate a aar file to this folder xxx\testUnityPackage\app\build\outputs\aar

Then change the file extension to zip

use winrar to open it and del the classes.jar and change back to aar extension

Then the aar file is ready for unity.
Open a new project in unity
create new button

create new empty game object and add component > new script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class controller : MonoBehaviour {

    public Button loginBtn;

    // Use this for initialization
	void Start () {
        loginBtn.onClick.AddListener(loginAction);
	}
	
	// Update is called once per frame
	void Update () {
		
	}

    void loginAction()
    {
        Debug.Log("You have clicked the button!");
        using (AndroidJavaClass jc = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        {
            using (AndroidJavaObject jo = jc.GetStatic<AndroidJavaObject>("currentActivity"))
            {
                jo.Call("ShowToast", "Unity use Android's AlertDialog");
            }
        }
    }
}

then go to assets windows
create folder Plugins>Android
put the aar file and AndroidManifest.xml to the folder

aar location:
xxx\testUnityPackage\app\build\outputs\aar

AndroidManifest.xml location:
xxx\GIT\testUnityPackage\app\src\main\AndroidManifest.xml

and most important thing is since we have use com.android.support:appcompat-v7 in android studio and we are using gradle method to import the lib, unity will not auto import that library, so we have to copy the v7 lib to the unity, which is location at
C:\Users\xxx\AppData\Local\Android\sdk\extras\android\m2repository\com\android\support\appcompat-v7\xxx.aar

Unity go to build setting=>Android=>PlayerSetting
change the package name, it should be as same as your android studio aar project

Create a project
File->new->new module->android Library

create a class , and modify string.xml for testing

之後打開gradle

assemble then it will create 2 aar

Create a new project>change to project view, insert the aar file to app>libs folder

and change the gradle(apps)

try to execute the apps

Android resource linking failed
xxx/res/layout/login_landscape.xml:2: error: attribute layout_constraintBottom_toBottomOf (aka xxx:layout_constraintBottom_toBottomOf) not found.

<EditText
    android:id="@+id/editText2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:ems="10"
    android:inputType="textPersonName"
    android:background="@drawable/text_field_bg"
    android:padding="5dp"
    android:hint="請輸入帳號(4-16英數)"/>

File-based resource names must contain only lowercase a-z, 0-9, or underscore