Android项目实战之：无需重启应用和当前页面实现一键换肤
前言
Android应用中每个页面都有自己的主题风格，而主题样式可以在Style.xml里面自定义。自然就可以在这里面做文章，并且便于管理，本篇我们主要讲解下开源换肤框架MultipleTheme的使用，助你轻松实现换肤需求。
GitHub地址：https://github.com/dersoncheng/MultipleTheme
使用步骤
1，首先在attrs.xml里面定义属性：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<attr name="main_bg" format="reference|color"/>
<attr name="main_textcolor" format="reference|color"/>
<attr name="second_bg" format="reference|color"/>
<attr name="second_textcolor" format="reference|color"/>
</resources>
2，然后在style.xml里面设置相应的属性值：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="theme_1" >
<item name="main_bg">@color/bg_main_normal</item>
<item name="main_textcolor">@color/textcolor_main_normal</item>
<item name="second_bg">@color/bg_second_normal</item>
<item name="second_textcolor">@color/textcolor_second_normal</item>
</style>
<style name="theme_2">
<item name="main_bg">@color/bg_main_dark</item>
<item name="main_textcolor">@color/textcolor_main_dark</item>
<item name="second_bg">@color/bg_second_dark</item>
<item name="second_textcolor">@color/textcolor_second_dark</item>
</style>
</resources>
3，在color.xml中定义相应的颜色值：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="bg_main_normal">#ffffff</color>
<color name="textcolor_main_normal">#ff0000</color>
<color name="bg_main_dark">#000000</color>
<color name="textcolor_main_dark">#ffffff</color>
<color name="bg_second_normal">#0000ff</color>
<color name="textcolor_second_normal">#00ff00</color>
<color name="bg_second_dark">#ffffff</color>
<color name="textcolor_second_dark">#000000</color>
</resources>
经过以上三步我们就已经成功创建了两套主题，接下来关键是怎么应用这两套主题：
1，在BaseActivity的oncreate（）创建Activity实例时，根据SharedPreference拿到当前应该显示什么主题，并setTheme()，然后布局文件各元素会自定获取Style.xml定义好的属性进行展示；
public class BaseActivity extends Activity{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(SharedPreferencesMgr.getInt("theme", 0) == 1) {
setTheme(R.style.theme_2);
} else {
setTheme(R.style.theme_1);
}
}
}
2，相应的布局文件如下：
针对切换主题模式时需要立即更新页面ui的页面，需要使用框架里的封装控件，修改相应属性的值为”?attr/xx”。
<derson.com.multipletheme.colorUi.widget.ColorRelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="?attr/main_bg"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin">
<derson.com.multipletheme.colorUi.widget.ColorTextView
android:textColor="?attr/main_textcolor"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
<derson.com.multipletheme.colorUi.widget.ColorButton
android:id="@+id/btn"
android:text="换肤"
android:layout_centerInParent="true"
android:textColor="?attr/main_textcolor"
android:layout_width="100dip"
android:layout_height="80dip" />
<derson.com.multipletheme.colorUi.widget.ColorButton
android:id="@+id/btn_2"
android:layout_centerHorizontal="true"
android:text="下一页"
android:layout_below="@id/btn"
android:layout_marginTop="30dip"
android:textColor="?attr/main_textcolor"
android:layout_width="100dip"
android:layout_height="80dip" />
</derson.com.multipletheme.colorUi.widget.ColorRelativeLayout>
3，MainActivity代码，其中SharedPreferencesMgr是SharedPreferences保存数据的工具类：
public class MainActivity extends BaseActivity {
ColorButton btn,btn_next;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (ColorButton)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 根据主题标志设置相应主题
if(SharedPreferencesMgr.getInt("theme", 0) == 1) {
SharedPreferencesMgr.setInt("theme", 0);
setTheme(R.style.theme_1);
} else {
SharedPreferencesMgr.setInt("theme", 1);
setTheme(R.style.theme_2);
}
final View rootView = getWindow().getDecorView();
rootView.setDrawingCacheEnabled(true);
rootView.buildDrawingCache(true);
final Bitmap localBitmap = Bitmap.createBitmap(rootView.getDrawingCache());
rootView.setDrawingCacheEnabled(false);
if (null != localBitmap && rootView instanceof ViewGroup) {
final View localView = new View(getApplicationContext());
localView.setBackgroundDrawable(new BitmapDrawable(getResources(), localBitmap));
ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
((ViewGroup) rootView).addView(localView, params);
localView.animate().alpha(0).setDuration(1000).setListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
ColorUiUtil.changeTheme(rootView, getTheme());
}
@Override
public void onAnimationEnd(Animator animation) {
((ViewGroup) rootView).removeView(localView);
localBitmap.recycle();
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
}).start();
}
} else {
ColorUiUtil.changeTheme(rootView, getTheme());
}
}
});
btn_next = (ColorButton)findViewById(R.id.btn_2);
btn_next.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this, SecondActivity.class));
}
});
}
}
上面得到DecorView的视图，这里会复制当前RootView(根视图)覆盖到当前视图上面，然后调用动画改变其透明度。这里注册动画监听函数（AnimatorListener）,在onAnimatorStart[动画开始执行]会根据改变的主题样式去同步改变各控件样式，在onAnimatorEnd[动画执行完毕]会删掉复制的RootView;
这里同步改变各控件主题样式的触发操作主要由ColorUiUtil完成：
public class ColorUiUtil {
/**
* 切换应用主题
*
* @param rootView
*/
public static void changeTheme(View rootView, Resources.Theme theme) {
if (rootView instanceof ColorUiInterface) {
((ColorUiInterface) rootView).setTheme(theme);
if (rootView instanceof ViewGroup) {
int count = ((ViewGroup) rootView).getChildCount();
for (int i = 0; i < count; i++) {
changeTheme(((ViewGroup) rootView).getChildAt(i), theme);
}
}
if (rootView instanceof AbsListView) {
try {
Field localField = AbsListView.class.getDeclaredField("mRecycler");
localField.setAccessible(true);
Method localMethod = Class.forName("android.widget.AbsListView$RecycleBin").getDeclaredMethod("clear", new Class[0]);
localMethod.setAccessible(true);
localMethod.invoke(localField.get(rootView), new Object[0]);
} catch (NoSuchFieldException e1) {
e1.printStackTrace();
} catch (ClassNotFoundException e2) {
e2.printStackTrace();
} catch (NoSuchMethodException e3) {
e3.printStackTrace();
} catch (IllegalAccessException e4) {
e4.printStackTrace();
} catch (InvocationTargetException e5) {
e5.printStackTrace();
}
}
} else {
if (rootView instanceof ViewGroup) {
int count = ((ViewGroup) rootView).getChildCount();
for (int i = 0; i < count; i++) {
changeTheme(((ViewGroup) rootView).getChildAt(i), theme);
}
}
if (rootView instanceof AbsListView) {
try {
Field localField = AbsListView.class.getDeclaredField("mRecycler");
localField.setAccessible(true);
Method localMethod = Class.forName("android.widget.AbsListView$RecycleBin").getDeclaredMethod("clear", new Class[0]);
localMethod.setAccessible(true);
localMethod.invoke(localField.get(rootView), new Object[0]);
} catch (NoSuchFieldException e1) {
e1.printStackTrace();
} catch (ClassNotFoundException e2) {
e2.printStackTrace();
} catch (NoSuchMethodException e3) {
e3.printStackTrace();
} catch (IllegalAccessException e4) {
e4.printStackTrace();
} catch (InvocationTargetException e5) {
e5.printStackTrace();
}
}
}
}
}
最重要的一点是需要动态变换主题的组件都要使用自定义组件，个别没有的根据规则可以自己实现：
这个框架对换肤操作的确管用,但是需要自己去设置对应的自定义组件，感觉代码量颇大，可定制型不是很强，而且功能解耦不是很清晰。
如果你用的控件它的框架中并没有，那就照着作者写的另写一个吧。比如我用的design包下的TabLayout，那么就复制一份作者写的控件，修改为extends TabLayout：
public class ColorTabLayout extends TabLayout implements ColorUiInterface {
private int attr_background = -1;
public ColorTabLayout(Context context) {
super(context);
}
public ColorTabLayout(Context context, AttributeSet attrs) {
super(context, attrs);
this.attr_background = ViewAttributeUtil.getBackgroundAttibute(attrs);
}
public ColorTabLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.attr_background = ViewAttributeUtil.getBackgroundAttibute(attrs);
}
@Override
public View getView() {
return this;
}
@Override
public void setTheme(Resources.Theme themeId) {
if(attr_background != -1) {
ViewAttributeUtil.applyBackgroundDrawable(this, themeId, attr_background);
}
}
}
然后该怎么用怎么用：
<com.monkey.zhuishu.changeTheme.widget.ColorTabLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="@dimen/base_title_height"
android:layout_below="@+id/titleBar"
android:background="?attr/activity_bg"
app:tabIndicatorColor="?attr/indicator_color"
app:tabSelectedTextColor="@color/tabSelectedText"
app:tabTextColor="@color/tabUnSelectedText">
</com.monkey.zhuishu.changeTheme.widget.ColorTabLayout>