Android FloatingActionButton，Snackbar

FloatingActionButton 浮動按鈕

<android.support.design.widget.FloatingActionButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="end|bottom"
    android:id="@+id/float_btn"/>

Snackbar可以用來代替Toast

//coordinatorLayout爲Snackbar顯示的容器
//float btn爲顯示內容
//Undo爲提示框右側點擊按鈕的文字
Snackbar.make(coordinatorLayout, "float btn", Snackbar.LENGTH_SHORT)
   .setAction("Undo", new View.OnClickListener() {
       @Override
       public void onClick(View v) {

       }
   })
   .show();

只要使用CoordinatorLayout作爲基本佈局，將自動產生向上移動的動畫。浮動操作按鈕有一個 默認的 behavior來檢測Snackbar的添加並讓按鈕在Snackbar之上呈現上移與Snackbar等高的動畫。

<android.support.design.widget.CoordinatorLayout
        android:id="@+id/main_content"
        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="match_parent">

自定義FloatingActionButton在CoordinatorLayout中的動畫
參考http://blog.csdn.net/xyz_lmn/article/details/48055919
神奇之處在於Behavior對象，CoordinatorLayout自己並不控制View，所有的控制權都在Behavior。
通過 CoordinatorLayout.Behavior(YourView.Behavior.class) 來定義自己的Behavior，並在layout 文件中設置 app:layout_behavior=”com.example.app.YourView$Behavior” 來達到效果。
如下面的例子，實現了點擊FloatingActionButton點擊旋轉90度，並適配Snackbar。

public class RotateBehavior  extends CoordinatorLayout.Behavior<FloatingActionButton> {
    private static final String TAG = RotateBehavior.class.getSimpleName();

    public RotateBehavior() {
    }

    public RotateBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
        return dependency instanceof Snackbar.SnackbarLayout;
    }

    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
        float translationY = getFabTranslationYForSnackbar(parent, child);
        float percentComplete = -translationY / dependency.getHeight();
        child.setRotation(-90 * percentComplete);
        child.setTranslationY(translationY);
        return false;
    }

    private float getFabTranslationYForSnackbar(CoordinatorLayout parent,
                                                FloatingActionButton fab) {
        float minOffset = 0;
        final List<View> dependencies = parent.getDependencies(fab);
        for (int i = 0, z = dependencies.size(); i < z; i++) {
            final View view = dependencies.get(i);
            if (view instanceof Snackbar.SnackbarLayout && parent.doViewsOverlap(fab, view)) {
                minOffset = Math.min(minOffset,
                        ViewCompat.getTranslationY(view) - view.getHeight());
            }
        }

        return minOffset;
    }
}

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="end|bottom"
        android:layout_margin="@dimen/fab_margin"
        android:src="@drawable/ic_done"
        app:layout_behavior="com.meizu.coordinatorlayoutdemo.RotateBehavior"/>
</android.support.design.widget.CoordinatorLayout>