MultipleTheme换肤功能详解

前段时间刚好看到一篇换肤开源框架，MultipleTheme，这边来研究研究到底怎么实现的：

Android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。

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>

然后在style.xml里面设置相应的属性值：

• 这里分为theme1, theme2。分别对应不同的主题风格；

<?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>

相应的颜色值color.xml中去定义：

<?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>

重点是怎么去用主题，具体讲解如下：

所有的Activity都继承BaseActivity，在oncreate（）创建Activity实例时，会设置该Activity的Theme(主题)，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；

package derson.com.multipletheme;

import android.app.Activity;
import android.os.Bundle;
import android.os.PersistableBundle;

import derson.com.multipletheme.colorUi.util.SharedPreferencesMgr;

/** * Created by chengli on 15/6/14. */
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);
        }
    }
}

相应的布局文件

<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>

我们来看看MainActivity：

package derson.com.multipletheme;

import android.animation.Animator;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.os.Build;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;

import derson.com.multipletheme.colorUi.util.ColorUiUtil;
import derson.com.multipletheme.colorUi.util.SharedPreferencesMgr;
import derson.com.multipletheme.colorUi.widget.ColorButton;


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) {
                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();
                if(Build.VERSION.SDK_INT >= 14) {
                    rootView.setDrawingCacheEnabled(true);
                    rootView.buildDrawingCache(true);
                    final Bitmap localBitmap = Bitmap.createBitmap(rootView.getDrawingCache());
                    rootView.setDrawingCacheEnabled(false);
                    if (null != localBitmap && rootView instanceof ViewGroup) {
                        final View localView2 = new View(getApplicationContext());
                        localView2.setBackgroundDrawable(new BitmapDrawable(getResources(), localBitmap));
                        ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
                        ((ViewGroup) rootView).addView(localView2, params);
                        localView2.animate().alpha(0).setDuration(400).setListener(new Animator.AnimatorListener() {
                            @Override
                            public void onAnimationStart(Animator animation) {
                                ColorUiUtil.changeTheme(rootView, getTheme());
                            }

                            @Override
                            public void onAnimationEnd(Animator animation) {
                                ((ViewGroup) rootView).removeView(localView2);
                                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));
            }
        });
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

在MainActivity中，我们设置一个切换主题点击事件。这里我们会把主题标志保存到本地，这里用到的是SharedPreferencesMgr：

package derson.com.multipletheme.colorUi.util;

import android.content.Context;
import android.content.SharedPreferences;

/** * SharedPreferences管理类 */
public class SharedPreferencesMgr {

    private static Context context;
    private static SharedPreferences sPrefs;

    private SharedPreferencesMgr(Context context, String fileName) {
        this.context = context;
        sPrefs = context.getSharedPreferences(
                fileName, Context.MODE_WORLD_READABLE);
    }

    public static void init(Context context, String fileName) {
        new SharedPreferencesMgr(context, fileName);
    }

    public static String fileName;

    public static int getInt(String key, int defaultValue) {
        return sPrefs.getInt(key, defaultValue);
    }

    public static void setInt(String key, int value) {
        sPrefs.edit().putInt(key, value).commit();
    }

    public static boolean getBoolean(String key, boolean defaultValue) {
        return sPrefs.getBoolean(key, defaultValue);
    }

    public static void setBoolean(String key, boolean value) {
        sPrefs.edit().putBoolean(key, value).commit();
    }

    public static String getString(String key, String defaultValue) {
        if (sPrefs == null)
            return defaultValue;
        return sPrefs.getString(key, defaultValue);
    }

    public static void setString(String key, String value) {
        if (sPrefs == null)
            return;
        sPrefs.edit().putString(key, value).commit();
    }

    public static void clearAll() {
        if (sPrefs == null)
            return;
        sPrefs.edit().clear().commit();
    }
}

在切换主题点击事件中逻辑看起来有点复杂，我们来一起分析分析吧；

• 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);
                }

• 根据版本不同设置动画，这里偷懒没有导入niceoldandroids ,所以做了版本区别。会得到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;

 final View rootView = getWindow().getDecorView();
                if(Build.VERSION.SDK_INT >= 14) {
                    rootView.setDrawingCacheEnabled(true);
                    rootView.buildDrawingCache(true);
                    final Bitmap localBitmap = Bitmap.createBitmap(rootView.getDrawingCache());
                    rootView.setDrawingCacheEnabled(false);
                    if (null != localBitmap && rootView instanceof ViewGroup) {
                        final View localView2 = new View(getApplicationContext());
                        localView2.setBackgroundDrawable(new BitmapDrawable(getResources(), localBitmap));
                        ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
                        ((ViewGroup) rootView).addView(localView2, params);
                        localView2.animate().alpha(0).setDuration(400).setListener(new Animator.AnimatorListener() {
                            @Override
                            public void onAnimationStart(Animator animation) {
                                ColorUiUtil.changeTheme(rootView, getTheme());
                            }

                            @Override
                            public void onAnimationEnd(Animator animation) {
                                ((ViewGroup) rootView).removeView(localView2);
                                localBitmap.recycle();
                            }

                            @Override
                            public void onAnimationCancel(Animator animation) {

                            }

                            @Override
                            public void onAnimationRepeat(Animator animation) {

                            }
                        }).start();
                    }
                } else {
                    ColorUiUtil.changeTheme(rootView, getTheme());
                }

这里同步改变各控件主题样式的触发操作主要由ColorUiUtil完成：

package derson.com.multipletheme.colorUi.util;

import android.app.Activity;
import android.content.res.Resources;
import android.provider.Settings;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.AbsListView;


import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import derson.com.multipletheme.colorUi.ColorUiInterface;

/** * Created by chengli on 15/6/10. */
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();
                }
            }
        }
    }


}

这里逻辑还是比较清晰的，会去遍历所有子视图，如果实现了ColorUiInterface接口，就会通过多态形式回调给实现该接口的实体，这里一点需要注意就是如果该控件是AbsListView的实体，这里会清空ReclycleBin里面的视图缓存（为什么这样做，目前我不是很清晰）；

• 例如：

package derson.com.multipletheme.colorUi.widget;

import android.content.Context;
import android.content.res.Resources;
import android.util.AttributeSet;
import android.view.View;


import derson.com.multipletheme.colorUi.ColorUiInterface;
import derson.com.multipletheme.colorUi.util.ViewAttributeUtil;

/** * Created by chengli on 15/6/8. */
public class ColorView extends View implements ColorUiInterface {

    private int attr_background = -1;

    public ColorView(Context context) {
        super(context);
    }

    public ColorView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.attr_background = ViewAttributeUtil.getBackgroundAttibute(attrs);
    }

    public ColorView(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);
        }
    }
}

主要是通过setTheme去改变该空间的样式,这里就要看一下ViewAttributeUtil干了些什么：

package derson.com.multipletheme.colorUi.util;


import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;
import android.widget.TextView;


import derson.com.multipletheme.colorUi.ColorUiInterface;

/** * Created by chengli on 15/6/8. */
public class ViewAttributeUtil {

    public static int getAttributeValue(AttributeSet attr, int paramInt) {
        int value = -1;
        int count = attr.getAttributeCount();
        for(int i = 0; i <count;i++) {
            if(attr.getAttributeNameResource(i) == paramInt) {
                String str = attr.getAttributeValue(i);
                if(null != str && str.startsWith("?")) {
                    value = Integer.valueOf(str.substring(1,str.length())).intValue();
                    return value;
                }
            }
        }
        return value;
    }

    public static int getBackgroundAttibute(AttributeSet attr) {
        return getAttributeValue(attr , android.R.attr.background);
    }

    public static int getCheckMarkAttribute(AttributeSet attr) {
        return getAttributeValue(attr, android.R.attr.checkMark);
    }

    public static int getSrcAttribute(AttributeSet attr) {
        return getAttributeValue(attr, android.R.attr.src);
    }

    public static int getTextApperanceAttribute(AttributeSet attr) {
        return getAttributeValue(attr, android.R.attr.textAppearance);
    }

    public static int getDividerAttribute(AttributeSet attr) {
        return getAttributeValue(attr, android.R.attr.divider);
    }

    public static int getTextColorAttribute(AttributeSet attr) {
        return getAttributeValue(attr, android.R.attr.textColor);
    }

    public static void applyBackgroundDrawable(ColorUiInterface ci, Resources.Theme theme, int paramInt) {
        TypedArray ta = theme.obtainStyledAttributes(new int[]{paramInt});
        Drawable drawable = ta.getDrawable(0);
        if(null != ci) {
            (ci.getView()).setBackgroundDrawable(drawable);
        }
        ta.recycle();
    }

    public static void applyImageDrawable(ColorUiInterface ci, Resources.Theme theme, int paramInt) {
        TypedArray ta = theme.obtainStyledAttributes(new int[]{paramInt});
        Drawable drawable = ta.getDrawable(0);
        if(null != ci && ci instanceof ImageView) {
            ((ImageView)ci.getView()).setImageDrawable(drawable);
        }
        ta.recycle();
    }

    public static void applyTextAppearance(ColorUiInterface ci, Resources.Theme theme, int paramInt) {
        TypedArray ta = theme.obtainStyledAttributes(new int[]{paramInt});
        int resourceId = ta.getResourceId(0,0);
        if(null != ci && ci instanceof TextView) {
            ((TextView)ci.getView()).setTextAppearance(ci.getView().getContext(), resourceId);
        }
        ta.recycle();
    }

    public static void applyTextColor(ColorUiInterface ci, Resources.Theme theme, int paramInt) {
        TypedArray ta = theme.obtainStyledAttributes(new int[]{paramInt});
        int resourceId = ta.getColor(0,0);
        ((TextView)ci.getView()).setTextColor(resourceId);
        if(null != ci && ci instanceof TextView) {
        }
        ta.recycle();
    }

}

从代码中我们可以看出通过paramInt去获取当前主题中对应的属性值，然后根据属性值进行进行操作；

• 而paramInt是怎么被赋值的呢，这里我们还是来看一下各个自定义组件的构造函数,已经相应的赋值函数：

 public ColorRadioButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.attr_background = ViewAttributeUtil.getBackgroundAttibute(attrs);
        this.attr_textAppearance = ViewAttributeUtil.getTextApperanceAttribute(attrs);
    }

    public ColorRadioButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.attr_background = ViewAttributeUtil.getBackgroundAttibute(attrs);
        this.attr_textAppearance = ViewAttributeUtil.getTextApperanceAttribute(attrs);
    }

 public static int getAttributeValue(AttributeSet attr, int paramInt) {
        int value = -1;
        int count = attr.getAttributeCount();
        for(int i = 0; i <count;i++) {
            if(attr.getAttributeNameResource(i) == paramInt) {
                String str = attr.getAttributeValue(i);
                if(null != str && str.startsWith("?")) {
                    value = Integer.valueOf(str.substring(1,str.length())).intValue();
                    return value;
                }
            }
        }
        return value;
    }

一目了然，主要是通过AttributeSet去获取paramInt相应的参数；

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：

大体的功能应该就这么多吧。

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。

抽个时间我们看下ColorFul,看看对上述疑问有没有进一步的优化。