多个开关按钮

Question

我是Android开发新手，有一个关于多个开关按钮的问题，如何智能地检索值，并使这些数据可用于其他活动？

目前，我实现了按钮状态的保存和当前活动中找到的信息的检索，如下所示：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    switchButtonOne = findViewById(R.id.switchButtonOne);
    switchButtonOne.setChecked(true);

    switchButtonTwo = findViewById(R.id.switchButtonTwo);
    switchButtonTwo.setChecked(false);

    //...... (In total there are 5 switch buttons)

    //switchButtonOne
    switchButtonOne.setOnCheckedChangeListener((compoundButton, isChecked) -> {
        if(isChecked){
            stringArrayList.add("1");
        }else {
            stringArrayList.remove("1");
        }
        getArray(stringArrayList);
        //SAVE
        sharedPreferences[0] = PreferenceManager
                .getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = sharedPreferences[0].edit();
        editor.putBoolean("1", switchButtonOne.isChecked());
        editor.commit();
    });
    switchButtonOne.setChecked(sharedPreferences[0].getBoolean("1", false));

    //switchButtonTwo
    switchButtonTwo.setOnCheckedChangeListener((compoundButton, isChecked) -> {
        if(isChecked){
            stringArrayList.add("2");
        }else {
            stringArrayList.remove("2");
        }
        getArray(stringArrayList);
        //SAVE
        sharedPreferences[0] = PreferenceManager
                .getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = sharedPreferences[0].edit();
        editor.putBoolean("2", switchButtonTwo.isChecked());
        editor.commit();
    });
    //.......
}

我确信有一种更有效的方法来实现这一点，我很高兴能够获得有效的资源来学习在活动之间提供信息和活动状态的最佳实践。

提前致谢

Answer 1

一种选择是对所有五个按钮仅使用一个侦听器。你可以这样做：

public class MyActivity extends Activity implements CompoundButton.OnCheckedChangeListener {
    Switch[] buttons;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        buttons = new Switch[5];
        Switch switchButtonOne = findViewById(R.id.switchButtonOne);
        switchButtonOne.setOnCheckedChangeListener(this);
        switchButtonOne.setChecked(sharedPreferences[0].getBoolean("1", false));
        buttons[0] = switchButtonOne;

        Switch switchButtonTwo = findViewById(R.id.switchButtonTwo);
        switchButtonTwo.setOnCheckedChangeListener(this);
        switchButtonTwo.setChecked(sharedPreferences[1].getBoolean("2", false));
        buttons[1] = switchButtonTwo;

        //...... (In total there are 5 switch buttons)
    }

    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        int index;
        switch (buttonView.getId()) {
            case R.id.switchButtonOne:
                index = 0;
                break;
            case R.id.switchButtonTwo:
                index = 1;
                break;
                ...
        }
        if (isChecked) {
            stringArrayList.add(String.valueOf(index + 1));
        } else {
            stringArrayList.remove(String.valueOf(index + 1));
        }
        getArray(stringArrayList);
        //SAVE
        sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = sharedPreferences[index].edit();
        editor.putBoolean(String.valueOf(index + 1), buttons[index].isChecked());
        editor.commit();
    }
}

此时代码并没有比你的短很多，但是，一旦你添加了其他三个按钮，你就会发现所有按钮的代码都变得更短更简洁了。

如果SharedPreferences 有一个BooleanArray，那就太好了，但是，这样的类不存在。可以找到解决方法here。

编辑

再次查看您的问题和完整代码，我建议采用不同的方法。你根本不需要任何OnCheckedChangeListener。只需在活动离开时保存按钮的状态 (onPause) 并在活动恢复后恢复状态 (onResume)。副作用是代码变得更短。

public class MainActivity extends Activity {
    Switch[] buttons;
    int numberOfButtons = 5;
    SharedPreferences sharedPreferences;

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

        buttons = new Switch[numberOfButtons];
        sharedPreferences = getSharedPreferences("YourPreferenceName", MODE_PRIVATE);

        for (int i = 0; i < numberOfButtons; i++) {
            buttons[i] = findViewById(getResources().getIdentifier("switchButton" + String.valueOf(i + 1), "id", getPackageName()));
        }
    }

    public void onPause() {
        super.onPause();
        for (int i = 0; i < numberOfButtons; i++) {
            SharedPreferences.Editor editor = sharedPreferences.edit();
            editor.putBoolean(String.valueOf(i + 1), buttons[i].isChecked());
            editor.apply();
        }
    }

    public void onResume(){
        super.onResume();
        for (int i = 0; i < numberOfButtons; i++) {
            buttons[i].setChecked(sharedPreferences.getBoolean(String.valueOf(i + 1), false));
        }
    }
}

请注意，在您的布局 xml 中，您必须将开关的 ID 更改为以下内容：switchButton1, ..., switchButton5。

Answer 2

您可以为整个活动实现CompoundButton.OnCheckedChangeListener，然后为您使用的所有开关设置监听器。在单个回调onCheckedChanged 中处理所有开关。

public class SwitchActivity extends Activity implements CompoundButton.OnCheckedChangeListener {
    Switch switchButtonOne;
    Switch switchButtonTwo;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState, @Nullable PersistableBundle persistentState) {

        super.onCreate(savedInstanceState, persistentState);
        switchButtonOne = findViewById(R.id.switchButtonOne);
        switchButtonOne.setChecked(true);

        switchButtonTwo = findViewById(R.id.switchButtonTwo);
        switchButtonTwo.setChecked(false);

        switchButtonOne.setOnCheckedChangeListener(this);
        switchButtonTwo.setOnCheckedChangeListener(this);
    }

    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        switch (buttonView.getId()) {
            case R.id.switchButtonOne:
                //Handle Code for switchButtonOne
                break;
            case R.id.switchButtonTwo:
                //Handle Code for switchButtonOne
                break;
        }
    }
}