Android Design Support Library - Snackbar使用

添加依赖：compile 'com.android.support:design:25.1.0'

介绍

Snackbar提供了一个介于Toast和AlertDialog之间轻量级控件，它可以很方便的提供消息的提示和动作反馈。Snackbar的使用与Toast的使用基本相同。用于在界面下面提示一些关键信息，跟Toast不同的地方是SnackBar允许用户向右滑动消除它，同时，也允许在SnackBar中设定一个Action，当用户点击了SnackBar里面的按钮的时候，可以进行一些操作，所以，功能绝对是很强大的。

[TOP]

SnackBar的构造 make方法

// 父容器，提示信息，持续时间
@NonNull
public static Snackbar make(@NonNull View view, @NonNull CharSequence text,
            @Duration int duration)
// 父容器，提示信息资源id，持续时间           
@NonNull
public static Snackbar make(@NonNull View view, @StringRes int resId, @Duration int duration)             

SnackBar的常用方法

设置点按钮及处理事件

// 用于给SnackBar设定一个Action，点击之后会回调OnclickListener中的Onclick方法，可以设置多个Action
public Snackbar setAction(CharSequence text, final View.OnClickListener listener)

设置字体颜色

public Snackbar setActionTextColor(@ColorInt int color)

设定提示的字体

public Snackbar setText(@NonNull CharSequence message)

展示SnackBar

public void show()

清除SnackBar

public void dismiss()

设置回调

public Snackbar setCallback(Callback callback)

回调类Callback，比较event

public static class Callback extends BaseCallback<Snackbar> {
        /** 滑动清除 */
        public static final int DISMISS_EVENT_SWIPE = BaseCallback.DISMISS_EVENT_SWIPE;
        /** 点击Action*/
        public static final int DISMISS_EVENT_ACTION = BaseCallback.DISMISS_EVENT_ACTION;
        /** 持续时间结束后*/
        public static final int DISMISS_EVENT_TIMEOUT = BaseCallback.DISMISS_EVENT_TIMEOUT;
        /** 调用dismiss方法*/
        public static final int DISMISS_EVENT_MANUAL = BaseCallback.DISMISS_EVENT_MANUAL;
        /** 以及有新的SnackBar产生*/
        public static final int DISMISS_EVENT_CONSECUTIVE = BaseCallback.DISMISS_EVENT_CONSECUTIVE;

        @Override
        public void onShown(Snackbar sb) {
            // Stub implementation to make API check happy.
        }

        @Override
        public void onDismissed(Snackbar transientBottomBar, @DismissEvent int event) {
            // Stub implementation to make API check happy.
       }
}

符：官方源码

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.support.design.widget;

import static android.support.annotation.RestrictTo.Scope.LIBRARY_GROUP;

import android.content.Context;
import android.content.res.ColorStateList;
import android.support.annotation.ColorInt;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.RestrictTo;
import android.support.annotation.StringRes;
import android.support.design.R;
import android.support.design.internal.SnackbarContentLayout;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.widget.FrameLayout;
import android.widget.TextView;

/**
 * Snackbars provide lightweight feedback about an operation. They show a brief message at the
 * bottom of the screen on mobile and lower left on larger devices. Snackbars appear above all other
 * elements on screen and only one can be displayed at a time.
 * 

 * They automatically disappear after a timeout or after user interaction elsewhere on the screen,
 * particularly after interactions that summon a new surface or activity. Snackbars can be swiped
 * off screen.
 * 

 * Snackbars can contain an action which is set via
 * {@link #setAction(CharSequence, android.view.View.OnClickListener)}.
 * 

 * To be notified when a snackbar has been shown or dismissed, you can provide a {@link Callback}
 * via {@link BaseTransientBottomBar#addCallback(BaseCallback)}.
 */
public final class Snackbar extends BaseTransientBottomBar<Snackbar> {

    /**
     * Show the Snackbar indefinitely. This means that the Snackbar will be displayed from the time
     * that is {@link #show() shown} until either it is dismissed, or another Snackbar is shown.
     *
     * @see #setDuration
     */
    public static final int LENGTH_INDEFINITE = BaseTransientBottomBar.LENGTH_INDEFINITE;

    /**
     * Show the Snackbar for a short period of time.
     *
     * @see #setDuration
     */
    public static final int LENGTH_SHORT = BaseTransientBottomBar.LENGTH_SHORT;

    /**
     * Show the Snackbar for a long period of time.
     *
     * @see #setDuration
     */
    public static final int LENGTH_LONG = BaseTransientBottomBar.LENGTH_LONG;

    /**
     * Callback class for {@link Snackbar} instances.
     *
     * Note: this class is here to provide backwards-compatible way for apps written before
     * the existence of the base {@link BaseTransientBottomBar} class.
     *
     * @see BaseTransientBottomBar#addCallback(BaseCallback)
     */
    public static class Callback extends BaseCallback<Snackbar> {
        /** Indicates that the Snackbar was dismissed via a swipe.*/
        public static final int DISMISS_EVENT_SWIPE = BaseCallback.DISMISS_EVENT_SWIPE;
        /** Indicates that the Snackbar was dismissed via an action click.*/
        public static final int DISMISS_EVENT_ACTION = BaseCallback.DISMISS_EVENT_ACTION;
        /** Indicates that the Snackbar was dismissed via a timeout.*/
        public static final int DISMISS_EVENT_TIMEOUT = BaseCallback.DISMISS_EVENT_TIMEOUT;
        /** Indicates that the Snackbar was dismissed via a call to {@link #dismiss()}.*/
        public static final int DISMISS_EVENT_MANUAL = BaseCallback.DISMISS_EVENT_MANUAL;
        /** Indicates that the Snackbar was dismissed from a new Snackbar being shown.*/
        public static final int DISMISS_EVENT_CONSECUTIVE = BaseCallback.DISMISS_EVENT_CONSECUTIVE;

        @Override
        public void onShown(Snackbar sb) {
            // Stub implementation to make API check happy.
        }

        @Override
        public void onDismissed(Snackbar transientBottomBar, @DismissEvent int event) {
            // Stub implementation to make API check happy.
        }
    }

    @Nullable private BaseCallback mCallback;

    private Snackbar(ViewGroup parent, View content, ContentViewCallback contentViewCallback) {
        super(parent, content, contentViewCallback);
    }

    /**
     * Make a Snackbar to display a message
     *
     * 
Snackbar will try and find a parent view to hold Snackbar's view from the value given
     * to {@code view}. Snackbar will walk up the view tree trying to find a suitable parent,
     * which is defined as a {@link CoordinatorLayout} or the window decor's content view,
     * whichever comes first.
     *
     * 
Having a {@link CoordinatorLayout} in your view hierarchy allows Snackbar to enable
     * certain features, such as swipe-to-dismiss and automatically moving of widgets like
     * {@link FloatingActionButton}.
     *
     * @param view     The view to find a parent from.
     * @param text     The text to show.  Can be formatted text.
     * @param duration How long to display the message.  Either {@link #LENGTH_SHORT} or {@link
     *                 #LENGTH_LONG}
     */
    @NonNull
    public static Snackbar make(@NonNull View view, @NonNull CharSequence text,
            @Duration int duration) {
        final ViewGroup parent = findSuitableParent(view);
        final LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        final SnackbarContentLayout content =
                (SnackbarContentLayout) inflater.inflate(
                        R.layout.design_layout_snackbar_include, parent, false);
        final Snackbar snackbar = new Snackbar(parent, content, content);
        snackbar.setText(text);
        snackbar.setDuration(duration);
        return snackbar;
    }

    /**
     * Make a Snackbar to display a message.
     *
     * 
Snackbar will try and find a parent view to hold Snackbar's view from the value given
     * to {@code view}. Snackbar will walk up the view tree trying to find a suitable parent,
     * which is defined as a {@link CoordinatorLayout} or the window decor's content view,
     * whichever comes first.
     *
     * 
Having a {@link CoordinatorLayout} in your view hierarchy allows Snackbar to enable
     * certain features, such as swipe-to-dismiss and automatically moving of widgets like
     * {@link FloatingActionButton}.
     *
     * @param view     The view to find a parent from.
     * @param resId    The resource id of the string resource to use. Can be formatted text.
     * @param duration How long to display the message.  Either {@link #LENGTH_SHORT} or {@link
     *                 #LENGTH_LONG}
     */
    @NonNull
    public static Snackbar make(@NonNull View view, @StringRes int resId, @Duration int duration) {
        return make(view, view.getResources().getText(resId), duration);
    }

    private static ViewGroup findSuitableParent(View view) {
        ViewGroup fallback = null;
        do {
            if (view instanceof CoordinatorLayout) {
                // We've found a CoordinatorLayout, use it
                return (ViewGroup) view;
            } else if (view instanceof FrameLayout) {
                if (view.getId() == android.R.id.content) {
                    // If we've hit the decor content view, then we didn't find a CoL in the
                    // hierarchy, so use it.
                    return (ViewGroup) view;
                } else {
                    // It's not the content view but we'll use it as our fallback
                    fallback = (ViewGroup) view;
                }
            }

            if (view != null) {
                // Else, we will loop and crawl up the view hierarchy and try to find a parent
                final ViewParent parent = view.getParent();
                view = parent instanceof View ? (View) parent : null;
            }
        } while (view != null);

        // If we reach here then we didn't find a CoL or a suitable content view so we'll fallback
        return fallback;
    }

    /**
     * Update the text in this {@link Snackbar}.
     *
     * @param message The new text for this {@link BaseTransientBottomBar}.
     */
    @NonNull
    public Snackbar setText(@NonNull CharSequence message) {
        final SnackbarContentLayout contentLayout = (SnackbarContentLayout) mView.getChildAt(0);
        final TextView tv = contentLayout.getMessageView();
        tv.setText(message);
        return this;
    }

    /**
     * Update the text in this {@link Snackbar}.
     *
     * @param resId The new text for this {@link BaseTransientBottomBar}.
     */
    @NonNull
    public Snackbar setText(@StringRes int resId) {
        return setText(getContext().getText(resId));
    }

    /**
     * Set the action to be displayed in this {@link BaseTransientBottomBar}.
     *
     * @param resId    String resource to display for the action
     * @param listener callback to be invoked when the action is clicked
     */
    @NonNull
    public Snackbar setAction(@StringRes int resId, View.OnClickListener listener) {
        return setAction(getContext().getText(resId), listener);
    }

    /**
     * Set the action to be displayed in this {@link BaseTransientBottomBar}.
     *
     * @param text     Text to display for the action
     * @param listener callback to be invoked when the action is clicked
     */
    @NonNull
    public Snackbar setAction(CharSequence text, final View.OnClickListener listener) {
        final SnackbarContentLayout contentLayout = (SnackbarContentLayout) mView.getChildAt(0);
        final TextView tv = contentLayout.getActionView();

        if (TextUtils.isEmpty(text) || listener == null) {
            tv.setVisibility(View.GONE);
            tv.setOnClickListener(null);
        } else {
            tv.setVisibility(View.VISIBLE);
            tv.setText(text);
            tv.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    listener.onClick(view);
                    // Now dismiss the Snackbar
                    dispatchDismiss(BaseCallback.DISMISS_EVENT_ACTION);
                }
            });
        }
        return this;
    }

    /**
     * Sets the text color of the action specified in
     * {@link #setAction(CharSequence, View.OnClickListener)}.
     */
    @NonNull
    public Snackbar setActionTextColor(ColorStateList colors) {
        final SnackbarContentLayout contentLayout = (SnackbarContentLayout) mView.getChildAt(0);
        final TextView tv = contentLayout.getActionView();
        tv.setTextColor(colors);
        return this;
    }

    /**
     * Sets the text color of the action specified in
     * {@link #setAction(CharSequence, View.OnClickListener)}.
     */
    @NonNull
    public Snackbar setActionTextColor(@ColorInt int color) {
        final SnackbarContentLayout contentLayout = (SnackbarContentLayout) mView.getChildAt(0);
        final TextView tv = contentLayout.getActionView();
        tv.setTextColor(color);
        return this;
    }

    /**
     * Set a callback to be called when this the visibility of this {@link Snackbar}
     * changes. Note that this method is deprecated
     * and you should use {@link #addCallback(BaseCallback)} to add a callback and
     * {@link #removeCallback(BaseCallback)} to remove a registered callback.
     *
     * @param callback Callback to notify when transient bottom bar events occur.
     * @deprecated Use {@link #addCallback(BaseCallback)}
     * @see Callback
     * @see #addCallback(BaseCallback)
     * @see #removeCallback(BaseCallback)
     */
    @Deprecated
    @NonNull
    public Snackbar setCallback(Callback callback) {
        // The logic in this method emulates what we had before support for multiple
        // registered callbacks.
        if (mCallback != null) {
            removeCallback(mCallback);
        }
        if (callback != null) {
            addCallback(callback);
        }
        // Update the deprecated field so that we can remove the passed callback the next
        // time we're called
        mCallback = callback;
        return this;
    }

    /**
     * @hide
     *
     * Note: this class is here to provide backwards-compatible way for apps written before
     * the existence of the base {@link BaseTransientBottomBar} class.
     */
    @RestrictTo(LIBRARY_GROUP)
    public static final class SnackbarLayout extends BaseTransientBottomBar.SnackbarBaseLayout {
        public SnackbarLayout(Context context) {
            super(context);
        }

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