Question

当屏幕旋转时，有没有办法保存代码中正在更改的变量？提前谢谢

Answer 1

您可以在停止活动时将值保存到instanceState Bundle中，并在启动时恢复它。像这样：

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    // Read values from the "savedInstanceState"
}

@Override
protected void onSaveInstanceState(Bundle outState) {
    // Save the values you need into "outState"
    super.onSaveInstanceState(outState);
}

Answer 2

扩展GSala的答案，这就是我如何做到的：

@Override
public void onSaveInstanceState(Bundle savedInstanceState){
    String someString = "this is a string";
    savedInstanceState.putString(CONSTANT_STRING, someString);
    //declare values before saving the state
    super.onSaveInstanceState(savedInstanceState);
}

然后在你的onCreate中你可以获得这样的值：

@Override
    public void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addContentView(R.layout.view);

        //Make sure to do this check otherwise someString will
        //cause an error when your activity first loads!
        if (savedInstanceState != null){
            //Do whatever you need with the string here, like assign it to variable.
            Log.d("XXX", savedInstanceState.getString(STRING_CONSTANT));
        }
}

这样，您也不必覆盖onRestoreInstanceState。此外，这可以通过任何变量或对象来完成，而不仅仅是字符串。

有关详细信息，请参阅this documentation。

Android：保存旋转时的变量和设置

2 个答案: