Question

我有3项活动 - 登录活动，主页活动，个人资料活动。登录活动将调用主页面活动，主页面活动将调用配置文件活动。如何将数据从登录活动传递到配置文件活动？是否必须首先将数据从登录活动传递到主页活动，然后从主页活动传递到配置文件活动？或者有没有其他方法来传递数据？谢谢！

Answer 1

您可以这样做......或者您可以将数据存储在持久存储中，并在需要时回读。

在此处了解SharedPreferences - Saving Key-Value Sets | SharedPreferences

保存数据如下：

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putInt(getString(R.string.saved_high_score), newHighScore);
editor.commit();

检索数据如下：

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
int defaultValue = getResources().getInteger(R.string.saved_high_score_default);
long highScore = sharedPref.getInt(getString(R.string.saved_high_score), defaultValue);

在此处了解SQLite Database - Saving Data in SQL Databases | SQLite Database

保存数据如下：

// Gets the data repository in write mode
SQLiteDatabase db = mDbHelper.getWritableDatabase();

// Create a new map of values, where column names are the keys
ContentValues values = new ContentValues();
values.put(FeedEntry.COLUMN_NAME_TITLE, title);
values.put(FeedEntry.COLUMN_NAME_SUBTITLE, subtitle);

// Insert the new row, returning the primary key value of the new row
long newRowId = db.insert(FeedEntry.TABLE_NAME, null, values);

检索数据如下：

SQLiteDatabase db = mDbHelper.getReadableDatabase();

// Filter results WHERE "title" = 'My Title'
String selection = FeedEntry.COLUMN_NAME_TITLE + " = ?";
String[] selectionArgs = { "My Title" };

// How you want the results sorted in the resulting Cursor
String sortOrder =
    FeedEntry.COLUMN_NAME_SUBTITLE + " DESC";

Cursor cursor = db.query(
    FeedEntry.TABLE_NAME,                     // The table to query
    projection,                               // The columns to return
    selection,                                // The columns for the WHERE clause
    selectionArgs,                            // The values for the WHERE clause
    null,                                     // don't group the rows
    null,                                     // don't filter by row groups
    sortOrder                                 // The sort order
    );

List itemIds = new ArrayList<>();
while(cursor.moveToNext()) {
  long itemId = cursor.getLong(
      cursor.getColumnIndexOrThrow(FeedEntry._ID));
  itemIds.add(itemId);
}
cursor.close();

Answer 2

在Android中的活动之间传递值有两种方法：

的 1。使用意图：
例如：
在Login Activity中，将以下代码放在OnClickListiner中：

Intent intent = new Intent(getApplicationContext(), mainActivity.class);
intent.putExtra("username", usernameVariable);
intent.putExtra("password", passwordVariable);
startActivity(intent);

然后，在mainActivity上，要接收值，请使用以下代码：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view);

    Intent intent = getIntent();

    String u = intent.getStringExtra("username");
    String p = intent.getStringExtra("password");
    // note: the arguments should match the same as its in the loginActivity
}

<强> 2。使用静态变量：
例如：

在LoginActivity上，创建两个静态属性。如下所示：

Public Class LoginActivity{
    public static String username;
    public static String password;

    protected void onCreate(Bundle savedInstanceState) {
        ...
    }
}

然后，在mainActivity类中使用以下代码来获取这些值：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view);

    String u=LoginActivity.username;
    String p=LoginActivity.password;
}

希望它能解决你的问题...

Answer 3

还有一种方法可以使用创建单例类并存储值并使用它。

public final class ProfileDataModel {

    private static ProfileDataModel instance;
    private String userName;
    private String address;

    private ProfileDataModel() {
    }

    /**
     * Get Instance for Profile
     * @return
     */
    public static ProfileDataModel getInstance() {
        if (instance == null){
            instance = new ProfileDataModel();
        }
        return instance;
    }


    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}


// Use cases 
//Set the data

ProfileDataModel.getInstance().setAddress("Data from login response");
ProfileDataModel.getInstance().setUserName("As per request/response");

//Get the data

String address = ProfileDataModel.getInstance().getAddress();
String userName = ProfileDataModel.getInstance().getUserName();

Android Studio活动传递数据

3 个答案: