comment ouvrir la classe google dans votre application Android par programme

Question

Je veux ouvrir google application de classe grâce à mon application existante. J'ai ajouté un bouton dans le tiroir de navigation pour cela. J'ai utilisé l'API google classroom pour cela, mais cela ne montre que le nom de la classe à laquelle je me suis inscrit. Je veux ouvrir l'application entière par le mien. J'ai essayé l'intention aussi mais je n'ai pas travaillé. S'il vous plaît dites-moi ce que je dois faire?

 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

Tout d'abord, vous devez avoir installé l'application en classe Google dans votre Android essayez cet extrait de code:

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