onCreateDrawableState中的setBackground

Question

我有一种情况，我需要在onCreateDrawableState中动态地根据条件对我的自定义按钮进行setBackground。所以我的代码是这样的

public class MyButton extends Button  {
public boolean nightMode = false;
private Drawable dayBackground, nightBackgound;
public MyButton(Context context, AttributeSet attrs) {
    super(context, attrs);
    setDuplicateParentStateEnabled(true);
    TypedArray a = context.getTheme().obtainStyledAttributes(
            attrs,
            R.styleable.QITheme,
            0, 0);

    try {
        dayBackground = a.getDrawable(R.styleable.MyTheme_dayBackground);
        nightBackgound = a.getDrawable(R.styleable.MyTheme_nightBackground);
    } finally {
        a.recycle();
    }

}
@Override
protected int[] onCreateDrawableState(int extraSpace) {
    int[] state = super.onCreateDrawableState(extraSpace+1);
    if (CurrentThemeManager.isNightMode()) {
        if(nightBackgound != null)
            setBackground(nightBackgound);
    } else {
        if(dayBackground != null)
            setBackground(dayBackground);
    }
    return state;
}

}

但是由于setBackground间接调用onCreateDrawableState，因此由于无限的递归调用，我得到了StackOverflowError

java.lang.StackOverflowError
        at android.view.ViewGroup.onCreateDrawableState(ViewGroup.java:5370)
        at android.view.View.onCreateDrawableState(View.java:14635)
        at android.view.ViewGroup.onCreateDrawableState(ViewGroup.java:5370)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:69)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76)
        at android.view.View.getDrawableState(View.java:14611)
        at android.view.View.setBackgroundDrawable(View.java:14837)
        at android.view.View.setBackground(View.java:14777)
        at my.mytheme.widget.MyButton.onCreateDrawableState(MyButton.java:76

有人能帮我修一下这个StackOverflowError吗？

Answer 1

您不应该从onCreateDrawableState调用setBackground。这是一种懒惰的方式。而是应该将状态从drawable更改。

像这样烹调：

在选择器中定义您的绘图对象(例如，使用state_checked)

​

<item android:state_checked="false"
    android:drawable="@drawable/night_image" />
<item android:state_checked="true"
    android:drawable="@drawable/day_image" />

1. 在自定义视图中添加状态处理

类YourFancyView扩展SomeView实现Checkable { private static final int[] CHECKED_STATE_SET ={ android.R.attr.state_checked }；@Override protected int[] onCreateDrawableState(int extraSpace) { final int[] drawableState = super.onCreateDrawableState(extraSpace + 1)；if (isChecked()) { mergeDrawableStates(drawableState，CHECKED_STATE_SET)；} return drawableState；} @Override public void setChecked(选中布尔值){ if(mChecked != checked) { mChecked = checked；refreshDrawableState()；}}

• 下一步-编码任何合理的方法来设置checked状态。

新的v= YourFancyView YourFancyView()；

if(itIsTime) v.setChecked(true);

这应该能起到作用。

Answer 2

我不确定这是否真的能解决您遇到的问题，但我认为您应该用setBackgroundDrawable()替换setBackground()