javascript - 让用户在edittext中输入一个简单的文本，然后在更多页面的textview中显示如何R.id string sharedpreferences

据我了解，SharedPreferences 只是您创建、编辑和获取值的文件。我将向您展示为您阐明其含义并帮助您实施它的步骤：

public class FirstActivity extends AppCompatActivity {

    Button saveInputBtn;
    EditText userInputET;
    SharedPreferences sharedPrefs;
    String userInput;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        saveInputBtn = findViewById(R.id.save_user_input);
        userInputET = findViewById(R.id.user_input);

        // 1) Affect an "onClickListener" to your button, that will inform your app when the user clicks on this button. 
        // The method saveTextAndLaunchSecondActivity() will only be launched if the button is clicked.
        saveInputBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                saveTextAndLaunchSecondActivity();
            }
        });
    }

    private void saveTextAndLaunchSecondActivity() {
        // 2) Get the input entered by the user inside your EditText
        String userInput = userInputET.getEditableText().toString();

        // 3) Create a file called sharedPrefName to stock values, that is "private" 
        // (so it cannot be accessed by other application than your)
        sharedPrefs = getSharedPreferences("sharedPrefName", Context.MODE_PRIVATE);

        // 4) Create an "Editor", that will allow you to edit the SharedPrerences 
        // file you just create.
        SharedPreferences.Editor editor = sharedPrefs.edit();

        // 5) Use the Editor to put a String value inside the file. 
        // The SharedPreferences use a "key-value" system to store values,
        // below, "KEYNAME" is the key and userInput is the value that we
        // fetched inside the EditText 
        editor.putString("KEYNAME", userInput);
        editor.apply();

        // 6) Create a intent that specify you want to go on another Activity
        // and use the "startActivity" method with the created Intent inside
        Intent intent = new Intent(this, SecondActivity.class);
        startActivity(intent);
    }
}

现在我们已经从 EditText 中提取了值并将其存储在 SharedPreferences 中，再加上启动 SecondActivity，我们需要检索这个 userInput。

在 SecondActivity 你可以使用这个：

public class SecondActivity extends AppCompatActivity {

    SharedPreferences sharedPrefs;
    TextView secondActivity_TV;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);

        secondActivity_TV = findViewById(R.id. TV_second_activity);

        // 7) Get the SharedPreferences file with its key : "sharedPrefName"
        sharedPrefs = getSharedPreferences("sharedPrefName", Context.MODE_PRIVATE);

        // 8) Get the userInput that you stored inside those SP
        // The key has to match the one you created, the value "hey" is the 
        // default value = the value that the SharedPreferences will give 
        // you if the key does not match
        String userInputReceived = sharedPrefs.getString("KEYNAME","hey");

        // 9) And now you can assign it to your TextView
        secondActivity_TV.setText(userInputReceived);
    }
}

然后，在 FirstActivity 中创建的 SharedPreferences 可以在任何其他活动中使用，只要您创建的键与您用来获取值的键相匹配。我真的希望这会对您有所帮助，如果您有任何疑问，请告诉我们进展如何！

javascript - 让用户在edittext中输入一个简单的文本，然后在更多页面的textview中显示如何R.id string sharedpreferences

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