あなたのアンドロイドアプリでGoogle教室をプログラムで開く方法

Question

私の既存のアプリを通じてGoogle教室のアプリを開きたいと思います。私はこのためにナビゲーション・ドロワーにボタンを追加しました。私はこれのためにGoogleの教室のAPIを使用していますが、それは私が登録した教室の名前だけを示しています。私は私のアプリ全体を開いてみたいです。私もやってみましたが、うまくいきませんでした。私が何をしなければならないか教えてください。

 Code: 

     package com.example.mi.mikpiadmin; 
     import com.google.android.gms.common.ConnectionResult; 
     import com.google.android.gms.common.GoogleApiAvailability; 
     import com.google.api.client.extensions.android.http.AndroidHttp; 
     import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential; 
     import com.google.api.client.googleapis.extensions.android.gms.auth.GooglePlayServicesAvailabilityIOException; 
     import com.google.api.client.googleapis.extensions.android.gms.auth.UserRecoverableAuthIOException; 

     import com.google.api.client.http.HttpTransport; 
     import com.google.api.client.json.JsonFactory; 
     import com.google.api.client.json.jackson2.JacksonFactory; 
     import com.google.api.client.util.ExponentialBackOff; 

     import com.google.api.services.classroom.ClassroomScopes; 

     import com.google.api.services.classroom.model.*; 

     import android.Manifest; 
     import android.accounts.AccountManager; 
     import android.app.Activity; 
     import android.app.Dialog; 
     import android.app.ProgressDialog; 
     import android.content.Context; 
     import android.content.Intent; 
     import android.content.SharedPreferences; 
     import android.content.pm.PackageManager; 
     import android.net.ConnectivityManager; 
     import android.net.NetworkInfo; 
     import android.os.AsyncTask; 
     import android.os.Bundle; 
     import android.support.annotation.NonNull; 
     import android.text.TextUtils; 
     import android.text.method.ScrollingMovementMethod; 
     import android.view.View; 
     import android.view.ViewGroup; 
     import android.widget.Button; 
     import android.widget.LinearLayout; 
     import android.widget.TextView; 

     import java.io.IOException; 
     import java.util.ArrayList; 
     import java.util.Arrays; 
     import java.util.List; 

     import pub.devrel.easypermissions.AfterPermissionGranted; 
     import pub.devrel.easypermissions.EasyPermissions; 

public class Google_Classroom extends Activity 
     implements EasyPermissions.PermissionCallbacks { 
    GoogleAccountCredential mCredential; 
    private TextView mOutputText; 
    private Button mCallApiButton; 
    ProgressDialog mProgress; 

    static final int REQUEST_ACCOUNT_PICKER = 1000; 
    static final int REQUEST_AUTHORIZATION = 1001; 
    static final int REQUEST_GOOGLE_PLAY_SERVICES = 1002; 
    static final int REQUEST_PERMISSION_GET_ACCOUNTS = 1003; 

    private static final String BUTTON_TEXT = "Call Classroom API"; 
    private static final String PREF_ACCOUNT_NAME = "accountName"; 
    private static final String[] SCOPES = { ClassroomScopes.CLASSROOM_COURSEWORK_STUDENTS }; 

    /** 
    * Create the main activity. 
    * @param savedInstanceState previously saved instance data. 
    */ 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     LinearLayout activityLayout = new LinearLayout(this); 
     LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
       LinearLayout.LayoutParams.MATCH_PARENT, 
       LinearLayout.LayoutParams.MATCH_PARENT); 
     activityLayout.setLayoutParams(lp); 
     activityLayout.setOrientation(LinearLayout.VERTICAL); 
     activityLayout.setPadding(16, 16, 16, 16); 

     ViewGroup.LayoutParams tlp = new ViewGroup.LayoutParams(
       ViewGroup.LayoutParams.WRAP_CONTENT, 
       ViewGroup.LayoutParams.WRAP_CONTENT); 

     mCallApiButton = new Button(this); 
     mCallApiButton.setText(BUTTON_TEXT); 
     mCallApiButton.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       Intent i; 
       PackageManager manager = getPackageManager(); 
       try { 
        i = manager.getLaunchIntentForPackage("com.google.api.services.classroom"); 
        if (i == null) 
         throw new PackageManager.NameNotFoundException(); 
        i.addCategory(Intent.CATEGORY_LAUNCHER); 
        startActivity(i); 
       } catch (PackageManager.NameNotFoundException e) { 

       } 
       mCallApiButton.setEnabled(false); 
       mOutputText.setText(""); 
       getResultsFromApi(); 
       mCallApiButton.setEnabled(true); 
      } 
     }); 
     activityLayout.addView(mCallApiButton); 

     mOutputText = new TextView(this); 
     mOutputText.setLayoutParams(tlp); 
     mOutputText.setPadding(16, 16, 16, 16); 
     mOutputText.setVerticalScrollBarEnabled(true); 
     mOutputText.setMovementMethod(new ScrollingMovementMethod()); 
     mOutputText.setText(
       "Click the \'" + BUTTON_TEXT +"\' button to test the API."); 
     activityLayout.addView(mOutputText); 

     mProgress = new ProgressDialog(this); 
     mProgress.setMessage("Calling Classroom API ..."); 

     setContentView(activityLayout); 

     // Initialize credentials and service object. 
     mCredential = GoogleAccountCredential.usingOAuth2(
       getApplicationContext(), Arrays.asList(SCOPES)) 
       .setBackOff(new ExponentialBackOff()); 
    } 



    /** 
    * Attempt to call the API, after verifying that all the preconditions are 
    * satisfied. The preconditions are: Google Play Services installed, an 
    * account was selected and the device currently has online access. If any 
    * of the preconditions are not satisfied, the app will prompt the user as 
    * appropriate. 
    */ 
    private void getResultsFromApi() { 
     if (! isGooglePlayServicesAvailable()) { 
      acquireGooglePlayServices(); 
     } else if (mCredential.getSelectedAccountName() == null) { 
      chooseAccount(); 
     } else if (! isDeviceOnline()) { 
      mOutputText.setText("No network connection available."); 
     } else { 
      new MakeRequestTask(mCredential).execute(); 
     } 
    } 

    /** 
    * Attempts to set the account used with the API credentials. If an account 
    * name was previously saved it will use that one; otherwise an account 
    * picker dialog will be shown to the user. Note that the setting the 
    * account to use with the credentials object requires the app to have the 
    * GET_ACCOUNTS permission, which is requested here if it is not already 
    * present. The AfterPermissionGranted annotation indicates that this 
    * function will be rerun automatically whenever the GET_ACCOUNTS permission 
    * is granted. 
    */ 
    @AfterPermissionGranted(REQUEST_PERMISSION_GET_ACCOUNTS) 
    private void chooseAccount() { 
     if (EasyPermissions.hasPermissions(
       this, Manifest.permission.GET_ACCOUNTS)) { 
      String accountName = getPreferences(Context.MODE_PRIVATE) 
        .getString(PREF_ACCOUNT_NAME, null); 
      if (accountName != null) { 
       mCredential.setSelectedAccountName(accountName); 
       getResultsFromApi(); 
      } else { 
       // Start a dialog from which the user can choose an account 
       startActivityForResult(
         mCredential.newChooseAccountIntent(), 
         REQUEST_ACCOUNT_PICKER); 
      } 
     } else { 
      // Request the GET_ACCOUNTS permission via a user dialog 
      EasyPermissions.requestPermissions(
        this, 
        "This app needs to access your Google account (via Contacts).", 
        REQUEST_PERMISSION_GET_ACCOUNTS, 
        Manifest.permission.GET_ACCOUNTS); 
     } 
    } 

    /** 
    * Called when an activity launched here (specifically, AccountPicker 
    * and authorization) exits, giving you the requestCode you started it with, 
    * the resultCode it returned, and any additional data from it. 
    * @param requestCode code indicating which activity result is incoming. 
    * @param resultCode code indicating the result of the incoming 
    *  activity result. 
    * @param data Intent (containing result data) returned by incoming 
    *  activity result. 
    */ 
    @Override 
    protected void onActivityResult(
      int requestCode, int resultCode, Intent data) { 
     super.onActivityResult(requestCode, resultCode, data); 
     switch(requestCode) { 
      case REQUEST_GOOGLE_PLAY_SERVICES: 
       if (resultCode != RESULT_OK) { 
        mOutputText.setText(
          "This app requires Google Play Services. Please install " + 
            "Google Play Services on your device and relaunch this app."); 
       } else { 
        getResultsFromApi(); 
       } 
       break; 
      case REQUEST_ACCOUNT_PICKER: 
       if (resultCode == RESULT_OK && data != null && 
         data.getExtras() != null) { 
        String accountName = 
          data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME); 
        if (accountName != null) { 
         SharedPreferences settings = 
           getPreferences(Context.MODE_PRIVATE); 
         SharedPreferences.Editor editor = settings.edit(); 
         editor.putString(PREF_ACCOUNT_NAME, accountName); 
         editor.apply(); 
         mCredential.setSelectedAccountName(accountName); 
         getResultsFromApi(); 
        } 
       } 
       break; 
      case REQUEST_AUTHORIZATION: 
       if (resultCode == RESULT_OK) { 
        getResultsFromApi(); 
       } 
       break; 
     } 
    } 

    /** 
    * Respond to requests for permissions at runtime for API 23 and above. 
    * @param requestCode The request code passed in 
    *  requestPermissions(android.app.Activity, String, int, String[]) 
    * @param permissions The requested permissions. Never null. 
    * @param grantResults The grant results for the corresponding permissions 
    *  which is either PERMISSION_GRANTED or PERMISSION_DENIED. Never null. 
    */ 
    @Override 
    public void onRequestPermissionsResult(int requestCode, 
              @NonNull String[] permissions, 
              @NonNull int[] grantResults) { 
     super.onRequestPermissionsResult(requestCode, permissions, grantResults); 
     EasyPermissions.onRequestPermissionsResult(
       requestCode, permissions, grantResults, this); 
    } 

    /** 
    * Callback for when a permission is granted using the EasyPermissions 
    * library. 
    * @param requestCode The request code associated with the requested 
    *   permission 
    * @param list The requested permission list. Never null. 
    */ 
    @Override 
    public void onPermissionsGranted(int requestCode, List<String> list) { 
     // Do nothing. 
    } 

    /** 
    * Callback for when a permission is denied using the EasyPermissions 
    * library. 
    * @param requestCode The request code associated with the requested 
    *   permission 
    * @param list The requested permission list. Never null. 
    */ 
    @Override 
    public void onPermissionsDenied(int requestCode, List<String> list) { 
     // Do nothing. 
    } 

    /** 
    * Checks whether the device currently has a network connection. 
    * @return true if the device has a network connection, false otherwise. 
    */ 
    private boolean isDeviceOnline() { 
     ConnectivityManager connMgr = 
       (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); 
     NetworkInfo networkInfo = connMgr.getActiveNetworkInfo(); 
     return (networkInfo != null && networkInfo.isConnected()); 
    } 

    /** 
    * Check that Google Play services APK is installed and up to date. 
    * @return true if Google Play Services is available and up to 
    *  date on this device; false otherwise. 
    */ 
    private boolean isGooglePlayServicesAvailable() { 
     GoogleApiAvailability apiAvailability = 
       GoogleApiAvailability.getInstance(); 
     final int connectionStatusCode = 
       apiAvailability.isGooglePlayServicesAvailable(this); 
     return connectionStatusCode == ConnectionResult.SUCCESS; 
    } 

    /** 
    * Attempt to resolve a missing, out-of-date, invalid or disabled Google 
    * Play Services installation via a user dialog, if possible. 
    */ 
    private void acquireGooglePlayServices() { 
     GoogleApiAvailability apiAvailability = 
       GoogleApiAvailability.getInstance(); 
     final int connectionStatusCode = 
       apiAvailability.isGooglePlayServicesAvailable(this); 
     if (apiAvailability.isUserResolvableError(connectionStatusCode)) { 
      showGooglePlayServicesAvailabilityErrorDialog(connectionStatusCode); 
     } 
    } 


    /** 
    * Display an error dialog showing that Google Play Services is missing 
    * or out of date. 
    * @param connectionStatusCode code describing the presence (or lack of) 
    *  Google Play Services on this device. 
    */ 
    void showGooglePlayServicesAvailabilityErrorDialog(
      final int connectionStatusCode) { 
     GoogleApiAvailability apiAvailability = GoogleApiAvailability.getInstance(); 
     Dialog dialog = apiAvailability.getErrorDialog(
       Google_Classroom.this, 
       connectionStatusCode, 
       REQUEST_GOOGLE_PLAY_SERVICES); 
     dialog.show(); 
    } 

    /** 
    * An asynchronous task that handles the Classroom API call. 
    * Placing the API calls in their own task ensures the UI stays responsive. 
    */ 
    private class MakeRequestTask extends AsyncTask<Void, Void, List<String>> { 
     private com.google.api.services.classroom.Classroom mService = null; 
     private Exception mLastError = null; 

     MakeRequestTask(GoogleAccountCredential credential) { 
      HttpTransport transport = AndroidHttp.newCompatibleTransport(); 
      JsonFactory jsonFactory = JacksonFactory.getDefaultInstance(); 
      mService = new com.google.api.services.classroom.Classroom.Builder(
        transport, jsonFactory, credential) 
        .setApplicationName("Classroom API Android Quickstart") 
        .build(); 
     } 

     /** 
     * Background task to call Classroom API. 
     * @param params no parameters needed for this task. 
     */ 
     @Override 
     protected List<String> doInBackground(Void... params) { 
      try { 
       return getDataFromApi(); 
      } catch (Exception e) { 
       mLastError = e; 
       cancel(true); 
       return null; 
      } 
     } 

     /** 
     * Fetch a list of the names of the first 10 courses the user has access to. 
     * @return List course names, or a simple error message if no courses are 
     *   found. 
     * @throws IOException 
     */ 
     private List<String> getDataFromApi() throws IOException { 
      ListCoursesResponse response = mService.courses().list() 
        .setPageSize(10) 
        .execute(); 
      List<Course> courses = response.getCourses(); 
      List<String> names = new ArrayList<String>(); 
      if (courses != null) { 
       for (Course course : courses) { 
        names.add(course.getName()); 
       } 
      } 
      return names; 
     } 


     @Override 
     protected void onPreExecute() { 
      mOutputText.setText(""); 
      mProgress.show(); 
     } 

     @Override 
     protected void onPostExecute(List<String> output) { 
      mProgress.hide(); 
      if (output == null || output.size() == 0) { 
       mOutputText.setText("No results returned."); 
      } else { 
       output.add(0, "Data retrieved using the Classroom API:"); 
       mOutputText.setText(TextUtils.join("\n", output)); 
      } 
     } 

     @Override 
     protected void onCancelled() { 
      mProgress.hide(); 
      if (mLastError != null) { 
       if (mLastError instanceof GooglePlayServicesAvailabilityIOException) { 
        showGooglePlayServicesAvailabilityErrorDialog(
          ((GooglePlayServicesAvailabilityIOException) mLastError) 
            .getConnectionStatusCode()); 
       } else if (mLastError instanceof UserRecoverableAuthIOException) { 
        startActivityForResult(
          ((UserRecoverableAuthIOException) mLastError).getIntent(), 
          Google_Classroom.REQUEST_AUTHORIZATION); 
       } else { 
        mOutputText.setText("The following error occurred:\n" 
          + mLastError.getMessage()); 
       } 
      } else { 
       mOutputText.setText("Request cancelled."); 
      } 
     } 
    } 
} 

Gradle file: 
apply plugin: 'com.android.application' 

android { 
    compileSdkVersion 25 
    buildToolsVersion "25.0.3" 
    defaultConfig { 
     applicationId "com.example.mi.mikpiadmin" 
     minSdkVersion 16 
     targetSdkVersion 25 
     versionCode 1 
     versionName "1.0" 
     testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" 
    } 
    buildTypes { 
     release { 
      minifyEnabled false 
      proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
     } 
    } 
} 

dependencies { 
    compile fileTree(dir: 'libs', include: ['*.jar']) 
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { 
     exclude group: 'com.android.support', module: 'support-annotations' 
    }) 

    compile 'com.android.support.constraint:constraint-layout:1.0.2' 
    compile 'com.android.support.constraint:constraint-layout:1.0.2' 
    compile 'com.android.support:cardview-v7:25.3.1' 
    compile 'com.android.volley:volley:1.0.0' 
    compile 'com.android.support:appcompat-v7:25.3.1' 
    compile 'com.android.support:design:25.3.1' 
    compile 'net.gotev:uploadservice:2.1' 
    compile 'com.google.android.gms:play-services-auth:11.4.0' 
    compile 'pub.devrel:easypermissions:0.3.0' 

     testCompile 'junit:junit:4.12' 
    compile('com.google.api-client:google-api-client-android:1.22.0') { 
     exclude group: 'org.apache.httpcomponents' 
    } 
    compile('com.google.apis:google-api-services-classroom:v1-rev64-1.22.0') { 
     exclude group: 'org.apache.httpcomponents' 
    } 
    android { 
     configurations.all { 
      resolutionStrategy.force 'com.google.code.findbugs:jsr305:1.3.9' 
     } 
    } 
} 

Answer 1

あなたがあなたのアンドロイドは、GoogleのClassroomアプリインストールしている必要がありますまず第一に、このコードスニペットを試してみてください。

Intent launchIntent = getPackageManager().getLaunchIntentForPackage("com.google.android.apps.classroom"); 
if (launchIntent != null) { 
    startActivity(launchIntent);//null pointer check in case package name was not found 
}