仿Android印象筆記底部導航欄

最近用上了印象筆記，覺得android 版的底部導航欄挺不錯的，好多應用里面都有用到，想著自己動手實現一下，不多說，先上圖：

要完成這樣的效果。需要自定義ViewGroup.
1、onMeasure（測量過程）
2、onLayout（布局）
3、添加動畫

onMeasure（測量過程）

@Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {


    int count = getChildCount();
    for (int i = 0; i<count;i++){
        View viewChild  = getChildAt(i);
        measureChild(viewChild,widthMeasureSpec,heightMeasureSpec);
    }
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}</pre> 

onLayout（布局）
 @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        View btn_main = getChildAt(getChildCount()-1);
        int left = 0;int top = 0;
        if (changed){
            for (int i = getChildCount()-1 ;i >= 0;i--){
                View viewChild  = getChildAt(i);
                int width = viewChild.getMeasuredWidth();
                int height = viewChild.getMeasuredHeight();
                left = getMeasuredWidth()- width;
                top = getMeasuredHeight() - height-distance;
                viewChild.layout(left,top,getMeasuredWidth(),getMeasuredHeight());
                distance += getDisension(100);
            }
            btn_main.setOnClickListener(this);
            changeState(currentState);
        }
    }
 
 
添加動畫

public void openTranslateAnimation(View view){
        distance = 0;
        RotateAnimation animation = new RotateAnimation(0f,45f, Animation.RELATIVE_TO_SELF,
                0.5f,Animation.RELATIVE_TO_SELF,0.5f);
        animation.setDuration(500);
        animation.setFillAfter(true);
        view.startAnimation(animation);
        for (int i = getChildCount()-2;i>= 0; i--){
            View childView = getChildAt(i);
            view.setVisibility(View.VISIBLE);
            TranslateAnimation translate = new TranslateAnimation(
                    Animation.RELATIVE_TO_SELF, 0, Animation.RELATIVE_TO_SELF, 0,
                    Animation.RELATIVE_TO_SELF, 0.35f, Animation.RELATIVE_TO_SELF, 0);
            translate.setDuration(100);
            translate.setStartOffset(10*offset);
            translate.setFillAfter(true);
            childView.startAnimation(translate);
            offset++;
        }
    }


public void closeTranslateAnimation(View view){
    distance = 0;
    RotateAnimation animation = new RotateAnimation(45f,0, Animation.RELATIVE_TO_SELF,
            0.5f,Animation.RELATIVE_TO_SELF,0.5f);
    animation.setDuration(500);
    animation.setFillAfter(true);
    view.startAnimation(animation);
    for (int i = getChildCount()-2;i>= 0; i--){
        View childView = getChildAt(i);
        view.setVisibility(View.VISIBLE);
        TranslateAnimation translate = new TranslateAnimation(
                Animation.RELATIVE_TO_SELF, 0, Animation.RELATIVE_TO_SELF, 0,
                Animation.RELATIVE_TO_SELF, 0, Animation.RELATIVE_TO_SELF, 0.35f);
        translate.setDuration(100);
        translate.setStartOffset(50*offset);
        childView.startAnimation(translate);
        offset++;
    }
}</pre> 

看一下主布局：
<com.xby.fm.view.StackMenu  android:layout_width="match_parent" android:layout_height="match_parent" android:layout_marginRight="20dp" android:layout_marginBottom="20dp" >


    <LinearLayout  android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center" >
        <TextView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:paddingRight="10dp" android:text="首頁" />

        <ImageView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@mipmap/ic_menu_item" />
    </LinearLayout>

    <LinearLayout  android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center" >
        <TextView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:paddingRight="10dp" android:text="我的音樂" />

        <ImageView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@mipmap/ic_menu_item" />
    </LinearLayout>

    <LinearLayout  android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center" >
        <TextView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:paddingRight="10dp" android:text="我的收藏" />

        <ImageView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@mipmap/ic_menu_item" />
    </LinearLayout>

    <LinearLayout  android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center" >
        <TextView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:paddingRight="10dp" android:text="個人中心" />

        <ImageView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@mipmap/ic_menu_item" />
    </LinearLayout>


        <ImageView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@mipmap/ic_main_menu" />
</com.xby.fm.view.StackMenu></pre> 

比較簡單，上一下git地址：StackMenu
</div>