java - 在 onSaveInstanceState 中保存图像按钮的 isSelected() 属性并恢复它

Question

假设我有一个图像按钮，它会更改图像 onClick() 因此 isSelected() 属性为真。如何在 onSaveInstanceState() 中保存此属性，以便稍后在旋转手机时恢复它？

Answer 1

首先，将isSelected()属性保存在onSaveInstanceState()

中

public final String STATE_SELECTED = "state_selected";

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    super.onSaveInstanceState(savedInstanceState);
    savedInstanceState.putBoolean(STATE_SELECTED, button.isSelected());
}

然后在onRestoreInstanceState()中访问并使用这个值

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    boolean selected = savedInstanceState.getBoolean(STATE_SELECTED);
    button.setSelected(selected);
    if (selected) // Do some stuff
    else //Do some other stuff
}

希望这对您有所帮助!

编辑:为回应您的评论，以下是您如何对一组按钮执行此操作:

public final String STATE_SELECTED = "state_selected";
public Button[] buttons; // This is populated elsewhere

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    super.onSaveInstanceState(savedInstanceState);
    boolean[] selected = new boolean[buttons.length];
    for (int i = 0; i < buttons.length; i++) selected[i] = buttons[i].isSelected();
    savedInstanceState.putBooleanArray(STATE_SELECTED, selected);
}

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    boolean[] selected = savedInstanceState.getBooleanArray(STATE_SELECTED);
    for (int i = 0; i < buttons.length; i++) button[i].setSelected(selected[i]);
}